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Glossary of basic biological terms and concepts
BUT
ABIOTIC ENVIRONMENT - a set of inorganic conditions (factors) for the habitat of organisms. These include the composition of atmospheric air, the composition of sea and fresh water, soil, air and soil temperature, lighting and other factors.
AGROBIOCENOSIS - a set of organisms living on lands occupied by crops and planting crops. In agriculture, the vegetation cover is created by man and usually consists of one or two cultivated plants and accompanying weeds.
AGROECOLOGY is a branch of ecology that studies the patterns of organization of artificial plant communities, their structure and functioning.
NITROGEN-FIXING BACTERIA - bacteria capable of assimilating atmospheric nitrogen with the formation of nitrogen compounds available for use by other organisms. Among A.b. there are both freely living in the soil, and coexisting with mutual benefit with the roots of higher plants.
ANTIBIOTICS are specific chemical substances formed by microorganisms and capable of exerting a selective effect on other microorganisms and malignant tumor cells even in small quantities. In a broad sense, A. also includes antimicrobial substances in the tissues of higher plants (phytoncides). The first A. was obtained in 1929 by Fleming (although penicillium was used by Russian doctors much earlier). The term "A." proposed in 1942 by Z. Waksman.
ANTHROPOGENIC FACTORS - factors of human influence on the environment. Human influence on plants can be both positive (plant cultivation, pest control, protection of rare species and biocenoses) and negative. The negative impact of a person can be direct - deforestation, collecting flowering plants, trampling vegetation in parks and forests, indirect - through environmental pollution, the destruction of pollinating insects, etc.
B
BACTERIA is the kingdom of living organisms. They differ from organisms of other kingdoms in the structure of the cell. Single-celled or grouped microorganisms. Motionless or mobile - with flagella.
BACTERICIDITY - the ability of plant juices, animal blood serum and some chemicals to kill bacteria.
BIO-INDICATORS - organisms whose developmental characteristics or number serve as indicators of natural processes or anthropogenic changes in the environment. Many organisms can exist only within certain, often narrow limits of changes in environmental factors (the chemical composition of soil, water, atmosphere, climatic and weather conditions, the presence of other organisms). For example, lichens and some coniferous trees serve B. to keep the air clean. Aquatic plants, their species composition and abundance are B. the degree of water pollution.
BIOMASS - the total mass of individuals of a species, group of species or community of organisms. It is usually expressed in units of mass (grams, kilograms) per unit area or volume of habitat (hectare, cubic meter). About 90% of biospheres of the entire biosphere are terrestrial plants. The rest is aquatic vegetation.
BIOSPHERE - the area of distribution of life on Earth, the composition, structure and energy of which are determined by the joint activity of living organisms.
BIOCENOSIS - a set of plants and animals in the food chain that has developed in the process of evolutionary development, affecting each other in the course of the struggle for existence and natural selection (plants, animals and microorganisms that inhabit the lake, river valley, pine forest).
AT
VIEW - the basic unit in the taxonomy of living organisms. A set of individuals that have a number of common characteristics and are capable of interbreeding with the formation of fertile offspring, inhabiting a certain territory.
germination - the ability of seeds to produce normal seedlings within a specified period under certain conditions. Express germination as a percentage.
HIGHER PLANTS - complex multicellular organisms with well-defined vegetative organs, adapted, as a rule, to life in a terrestrial environment.
G
GAMETE - sex cell. Provides transmission of hereditary information from parents to descendants.
Gametophyte - sexual generation in the life cycle of plants that develop with alternation of generations. Formed from spores, produces gametes. In higher plants, only in mosses, hyphae is represented by a leafy plant. In others, it is poorly developed and short-lived. In club mosses, horsetails, and ferns, G. is a growth that produces both male and female gametes. In angiosperms, the female G. is the embryo sac, and the male is pollen. They grow along the banks of rivers, in swamps and wet fields (reed, cattail).
GENERATIVE ORGANS - organs that perform the function of sexual reproduction. In flowering plants - flowers and fruits, more precisely - a speck of dust and an embryo sac.
HYBRIDIZATION - combining the hereditary material of different cells into one. In agriculture, the crossing of different varieties of plants. See also Selection.
Hygrophytes - plants of wet habitats. They grow in swamps, in water, in tropical rainforests. They have a poorly developed root system. Wood and mechanical fabrics are poorly developed. They can absorb moisture from the entire surface of the body.
HYDROPHYTES - aquatic plants attached to the ground and immersed in water only at the bottom. Unlike hygrophytes, they have well-developed conductive and mechanical tissues, a root system. But there are many intercellular spaces and air cavities.
GLYCOGEN - carbohydrate, polysaccharide. Its branched molecules are built from glucose residues. Energy reserve of many living organisms. When it is broken down, glucose (sugar) is formed and energy is released. Found in the liver and muscles of vertebrates, in fungi (yeast), in algae, in the grain of some varieties of corn.
GLUCOSE - grape sugar, one of the most common simple sugars. In green plants, it is formed from carbon dioxide and water as a result of photosynthesis. Participates in many metabolic reactions.
Gymnosperms are the most ancient of seed plants. Most are evergreen trees and shrubs. Representatives of gymnosperms are coniferous plants (spruce, pine, cedar, fir, larch).
MUSHROOMS - the kingdom of living organisms. Combine signs of both plants and animals, and also have special signs. There are both unicellular and multicellular fungi. The body (mycelium) consists of a system of branching filaments.
HUMUS (HUMUS) - a complex of specific dark-colored organic substances of the soil. It is obtained as a result of the transformation of organic residues. To a large extent determines the fertility of the soil.
D
Dioecious plants - plant species in which male (staminate) and female (pistillate) flowers are on different individuals (willow, poplar, sea buckthorn, actinidia).
DIFFERENTIATION - the emergence of differences between homogeneous cells and tissues.
WOOD is the water-conducting tissue of plants. The main conducting element is the vessels: dead lignified sex cells. It also includes fibers that perform a supporting function. It is characterized by annual increments: there are early (spring) and late (summer) wood.
BREATHING is one of the main vital functions, a set of processes that ensure the supply of oxygen to the body, its use in chemical reactions, as well as the removal of carbon dioxide and some other metabolic products from the body.
F
ANIMALS - the kingdom of living organisms. Unlike most plants, animals feed on ready-made organic substances and have a limited body growth in time. Their cells do not have a cellulose membrane. In the process of evolution, animals developed organ systems: digestive, respiratory, circulatory, etc.
PLANT LIFE FORM - the general appearance of a plant. There are trees, shrubs, shrubs, herbs.
VENATION OF LEAVES - a system of conducting bundles in leaf blades, along which substances are transported. There are parallel, arcuate, palmate, pinnate Zh.l.
W
RESERVES - small areas of a temporarily protected area with limited economic activity and visits of people. Individual species of plants or animals are preserved in sanctuaries.
RESERVES - large areas where the entire natural complex is preserved in a natural state. Any human activity is prohibited here.
GEM - an organism in the early period of development.
ZYGOTE - a cell formed as a result of the fusion of two gametes.
ZONAL VEGETATION - natural vegetation that characterizes natural belts and zones (tundra, taiga, steppe, desert, etc.).
And
IMMUNITY - immunity, resistance, the body's ability to protect its integrity. A particular manifestation of I. is immunity to infectious diseases.
INDICATORS - See indicator plants and Bioindicators.
INDICATOR PLANTS - plants or plant communities that are closely associated with certain environmental conditions and allow them to be qualitatively and quantitatively assessed by the presence of these plants or communities. I.r. are used in assessing the mechanical composition, the degree of acidity and salinity of soils, in the search for fresh water in deserts and some minerals. For example, the content of lead in the soil is indicated by the species of fescue and bent grass; zinc - types of violet and yarutka; copper and cobalt - resins, many cereals and mosses.
EVAPORATION - the transition of water into a gaseous state. The main organ that evaporates water from a plant through stomata is the leaf. Together with root pressure, it provides a constant flow of water through the roots, stems and leaves. Evaporation prevents the plant from overheating.
To
Calcephiles - plants that live in alkaline soils rich in calcium. Alkaline soils can be identified by vegetation: forest anemone, six-petal meadowsweet, larch.
CALCEPHOBS - plants that avoid limestone soils. These plants are able to bind heavy metals, the excess of which in acidic soils does not harm them. For example, peat mosses.
CAMBIA - a single-row layer of cells of the educational tissue, forming wood cells inward from itself, and bast cells outward.
Carotenes are orange-yellow pigments. synthesized by plants. K. is rich in green leaves (especially spinach), carrot roots, rose hips, currants, and tomatoes. K. - accompanying pigments of photosynthesis. The oxidized derivatives of K. are xanthophylls.
GLUTEN - proteins contained in wheat grain and, accordingly, in flour. They remain in the form of an elastic clot after the removal of starch from wheat dough. Baking qualities of wheat flour largely depend on the properties of K..
A CELL is the basic unit of all living organisms, an elementary living system. It can exist as a separate organism (bacteria, some algae and fungi, protozoan plants and animals) or as part of the tissues of multicellular organisms.
CONE OF GROWTH - the apical zone of the shoot or root, formed by the cells of the educational tissue. Provides shoot and root growth in length. Ph.D. the shoot is protected by rudimentary leaves, and the tip of the root growth is protected by a root cap.
CONCENTRATION - the amount of a substance in a unit of volume or mass.
ROOT SYSTEM - the totality of the roots of one plant. The degree of development of K.s. depends on the environment. A person can influence the development of K.s. plants (hilling, picking, tillage). There are rod and fibrous K.s.
rhizome - a perennial underground shoot that allows the plant to survive adverse conditions.
STARCH (STARCH) CROPS - cultivated plants that are cultivated to produce starch (potatoes, corn). Starch accumulates in tubers or fruits.
STARCH GRAINS - inclusions in plastids of plant cells. Growth K.z. occurs by imposing new layers of starch on the old ones, so the grains have a layered structure.
SILICA - silicon dioxide (quartz, quartz sand).
CROWN - elevated (above the stem) branched part of the tree.
Xanthophylls - natural pigments from the group of carotenes, their oxygen-containing derivatives. Contained in leaves, flowers, fruits and buds of higher plants, as well as in many algae and microorganisms. Participate in photosynthesis as additional pigments. In combination with other pigments, they create leaf color in autumn.
Xerophytes - plants of dry habitats, capable of withstanding overheating and dehydration due to a number of adaptive features.
CUTICLE - a layer of fatty substance that covers leaves, stems or fruits with a film. Low permeability to water, pathogens.
TILLERING - branching, in which lateral shoots appear from buds located near the surface of the earth and underground.
L
LITMUS is a coloring matter obtained from some lichens. The water infusion of L. is violet in color, turning blue from the action of alkalis and reddening from the action of acids. As an indicator in chemistry, “litmus paper” is used - filter paper dyed with a solution of L. With the help of L., the acidity of the water infusion of the soil can be determined.
LANDSCAPE - 1) type of terrain, 2) geographical landscape - a territory within which the relief, climate, vegetation and wildlife form typical outlines that give unity to the entire territory and distinguish it from neighboring territories.
LEUKOPLASTS - colorless plastids of a plant cell. They may have different shapes. One of the main functions is the synthesis and supply of nutrients: starch, oils. They can turn into chloroplasts.
LEAF MOSAIC - an arrangement of leaves that provides illumination for each shoot leaf. Perhaps due to the ability of the leaf petiole to grow for a long time and turn the leaf blade towards the light.
LEAF POSITION - the arrangement of leaves on a stem. There are alternate, opposite and whorled L.
LUB is a plant tissue that provides transport of photosynthesis products from leaves to places of consumption and storage. The main conducting element is living sieve tubes. L.'s fibers carry out mechanical function. Reserve nutrients are also deposited in the main cells of L..
M
OIL CROPS - cultural plants that are cultivated to produce fatty oils (sunflower, soybeans, mustard, castor beans, oil flax, sesame, etc.). Most M.K. accumulate oil in seeds and fruits.
INTERNODE - The section of a stem between two adjacent nodes. In rosette plants (dandelion, daisy), short shoots of trees (apple tree, birch), and some inflorescences (umbel, basket) M. are very short or absent.
INTERCELLULAR - spaces between cells. May be filled with air or water (more rarely).
INTERCELLULAR SUBSTANCE - a substance that connects cells to each other. The connection can be dense (in the integumentary tissue) or loose (in the storage tissue).
MESOPHITES - plants that live in conditions with sufficient, but not excessive soil moisture. Most of the plants in central Russia are found in the tropics and subtropics.
MYCOLOGY is a branch of biology that studies fungi.
MICROBIOLOGY - a branch of biology that studies microorganisms. The main object of M. is bacteria. However, the term "bacteriology" is used mainly in medicine. Yeast (the kingdom of fungi) also serves as a traditional object of M..
PERMANENT PLANTS - trees, shrubs, shrubs and herbaceous plants that live more than two years. They can bloom and bear fruit.
MOLECULE - the smallest particle of a substance that has the basic chemical properties of this substance. Consists of the same or different atoms.
PLANT MORPHOLOGY - the science that studies the structure of a plant and its forms.
UROUS ROOT SYSTEM - is formed with weak growth or death of the main root and intensive development of adventitious roots (buttercup, plantain, wheat).
MOSS (MOSSIVE) - department of higher plants. Most often these are terrestrial perennials. The body consists of a stem and leaves.
MULCHING - covering the surface of the soil with different materials in order to control weeds, preserve soil moisture and structure. For M., organic materials are used: peat chips, small manure, straw, as well as paper, cardboard, etc. M. helps to increase the yield of crops.
H
ABOVE-GROUND SEED GERMINATION - a method of seed germination, in which the cotyledons are brought to the surface (radish, buckwheat, beans, linden).
NATIONAL PARKS - large areas, usually located in picturesque places, where natural complexes of special value have been preserved. Unlike nature reserves, most of the N. p. open to the public.
LOWER PLANTS - a sub-kingdom of plants. Body N.R. (thallus or thallus) is not divided into root, stem and leaf. Such organisms have a special structure of cells, metabolism. K N.r. include only algae (see thallus). Previously, bacteria, lichens, algae, and fungi were included; all organisms except higher plants and animals.
NUCLEIC ACIDS are complex organic compounds whose biological role is to store and transmit hereditary information.
Dictionary of biological terms
(7cl)
Terms
Etymology
Definition
Autotrophs
From Greek. autos - himself, trophy - food
Organisms capable of independently synthesizing organic substances from inorganic substances using solar energy, the energy of chemical transformations. These are green plants and some bacteria.
anaerobic bacteria
From Greek. an - negative particle, aer - air, bios - life; bacterion bacterium
Organisms that can live and develop in the absence of free oxygen in the environment.
antennas
Short antennae in crustaceans
Antennas
Long antennae in crustaceans.
arterial blood
Blood saturated with oxygen.
archaebacteria
From Greek. archios - ancient, bacterion - coli
The oldest living prokaryotes appeared 3 billion years ago.
Aerobic organisms
From Greek. air - air, bios - life
Organisms that can live and develop only in the presence of free oxygen in the environment (all plants, most protozoa and multicellular animals, almost all fungi).
bacteriophage
From Greek. bacterion-coli, phagos-eater
A virus that infects bacteria.
bacilli
From lat. bacillus bacilli
elongated bacteria.
Biosphere
From Greek. bios - life, sphere - ball
The shell of the Earth inhabited by living organisms.
Biocenosis
From Greek. bios - life, koinos - common
The totality of animals, plants, fungi and microorganisms that co-occupy an area of land or water.
Binary nomenclature
From lat. binarius - double, consisting of two parts; nomenclature-painting names
Designation of species in two words: the first is the name of the genus, the second is the specific epithet.
Lateral line
The organ characteristic of fish that perceives the movement of water is formed by sensitive cells grouped on the lateral surfaces of the body.
Botany
From Greek. botane - grass
Plant science.
Frond
From the Greek bayon - palm branch
fern leaf
Deoxygenated blood
Blood that has given oxygen to the cells of the body.
vibrios
From the French vibrio - hesitate, tremble
curved bacteria
(the causative agent of cholera).
View
From lat. spices - standard, unit of measurement
Basic unit of classification. A set of individuals with a similar structure, lifestyle, capable of interbreeding with the appearance of fertile offspring and inhabiting a certain territory.
Virus
From lat. virus poison
non-cellular life form.
Virology
From Lat virus - poison; Greek logo teaching
The scientific discipline that studies viruses.
Water vascular system
characteristic of echinoderms. It is represented by an annular canal surrounding the esophagus, and five radial canals extending from it into the rays. Participates in locomotion, respiration and excretion.
Brood
Birds whose chicks soon after hatching are able to follow the mother and peck food on their own.
gametophyte
From Greek. gamete - wife, gametes - husband; phyto-plant
A plant that produces gametes.
Hemolymph
From Greek gem - blood, lat. lymph - pure water
A colorless or greenish liquid circulating in the vessels or intercellular cavities of many invertebrates (in arthropods, molluscs, etc.) that have an open circulatory system.
Genome
From Greek. genos- origin
The totality of genes in the haploid set of chromosomes of a given organism (the human gamete genome is represented by 23 chromosomes).
Hermaphroditism
From the names of the Greek the gods Hermes and Aphrodite; in translation means - a mythical bisexual creature.
The presence of male and female organs in the same individual.
Heterotrophs
From Greek. heteros - other, trophy - food
Organisms that use only ready-made organic substances for nutrition.
hydromedusa
From Greek. hidor - water, moisture;
Free-swimming sexual individuals of the hydroid class.
gifs
From Greek. hife - fabric, web
Microscopic branching threads that form the vegetative body of the fungus - thallus.
Mycelium
The vegetative body of the fungus (thallus), consisting of thin branching threads - hyphae. Serves for the absorption of nutrients from the substrate.
Caterpillar
A worm-like butterfly larva with a jointed body and no more than five pairs of legs.
double fertilization
A type of sexual process peculiar only to flowering plants. It lies in the fact that during the formation of the seed, not only the egg is fertilized, but also the central nucleus of the embryo sac.
Bilateral symmetry
Symmetry, in which the organs are located on both sides of the proposed plane, dividing the body lengthwise into two halves.
Diaphragm
From Greek. diaphragm - baffle
A muscular septum that separates the body cavity into the thoracic and abdominal sections.
diplococci
From Greek. di-two, cocco-grain
Bacteria consisting of pairwise contiguous cocci (two cells in one capsule).
Natural selection
The main driving factor in the evolution of organisms. The result of the struggle for existence is expressed in the predominant survival and leaving offspring of the most adapted individuals of each species of organisms and the death of the less adapted.
Zarostok
Sexual generation (gametophyte) in higher spore plants (mosses, horsetails, ferns). It develops from spores and forms male and female reproductive organs.
Zoology
From Greek. zoon-animal, logo-teaching
The science of animals that studies the diversity of the animal world, the structure and activity of animals, distribution, connection with the environment, patterns of individual and historical development.
Immunodeficiency
From lat. immunitas - release, deficiency - lacks
The inability of the body to resist any infections.
Instinct
From lat. instinctus - impulse
Complex, hereditarily determined behavior characteristic of individuals of a given species under certain conditions.
artificial selection
The choice by a person of the most economically valuable individuals of animals, plants, microorganisms of a given species, breed, variety, strain in order to obtain offspring from them with desirable properties.
Carotenoids
From lat. carota - carrots; Greek eidos - form, view
Red, yellow, and orange pigments found in plant and some animal tissues.
Cambium
From Greek. cambium - exchange
An educational tissue located between wood and bast and producing their growth in thickness.
Keel
A high crest on the sternum in most birds.
Classification
From lat. klass - category, class, fauer - do
The distribution of the entire set of living organisms according to a certain system of subordinate taxon groups (classes, families, genera, species, etc.)
Cloaca
Lat. cloaca
Expanded part of the hindgut into which the digestive, excretory and reproductive systems open.
cocci
From Greek. coconut grain
Bacteria having a spherical shape.
Cocoon
Fran. cocoon
Protective formation that protects eggs, embryos or pupae.
The colony
From lat. colony settlement
A group of individuals of one or more species living together that are able to live independently.
Competition
From lat. competitor - collide, run together
The relationship between organisms of the same species or different species competing for the same environmental resources with a lack of them.
cuticle in plants
From lat. cuticle - skin
A layer of fatty substance that covers the surface of the aerial organs of many plants with a continuous film. Plays a protective role.
cuticle in animals
From lat. cuticle-peel
Dense non-cellular formation on the surface of epithelial tissue cells.
Moult
Periodic change of outer covers and their various formations (scales, wool, feathers, etc.).
pseudopods
Temporary cytoplasmic outgrowths in unicellular organisms and some cells of multicellular animals (eg, coelenterates).
Beam symmetry
Symmetry, in which the same organs are located along the rays diverging from the center (sponges, coelenterates).
Mantle
From Greek. mantion - cloak
Two folds hanging from the molluscs on the sides of the body.
Uterus
A hollow muscular organ within which a baby develops.
Megaspore
From Greek. mega - large, spore-seed, sowing
Large female spores in ferns.
Mesoglea
From Greek. mezos - middle, intermediate; gleios - sticky
Structureless gelatinous substance lying between the ecto- and endoderm in sponges and coelenterates. Highly saturated with water (up to 98%).
mesoderm
from the Greek mesos-medium, derma-skin
Median embryo sac in multicellular animals, including humans.
Mycology
From Greek. mycos - mushroom, logo teaching, science
Mushroom science.
Mycorrhiza
From Greek. mykos - mushroom, riza - root
Symbiosis of the mycelium of the fungus and the roots of a higher plant.
Microbiology
From Greek. micros - small, bios - life, logos - science
The biological discipline that studies microorganisms.
microspore
From Greek. micro-small, spore-seed, sowing
Small male spores in ferns.
Mixotrophs
From lat. mixio mixing
Organisms with a mixed type of nutrition: they are capable of photosynthesis, but also feed on organic matter, eating bacteria and other protozoa.
Spawning
The spawning of reproductive products by fish - mature eggs and milk, followed by fertilization.
social insects
A number of groups of insects that form permanent (seasonal or perennial) associations - families consisting of breeding and working individuals.
Fan
Part of the feather, formed by a network of thin horny plates (beards) of the first and second order.
organism
From lat. body - give a slim look
Any living being, an integral system, a carrier of life, having a set of properties: metabolism, growth, development, reproduction, etc.
Parapodium
Lateral mobile outgrowths of the body with a tuft of setae in polychaete worms.
Pathogenic bacteria
From Greek. pathos - disease, genesis - origin
These are bacteria that cause severe diseases in humans and animals.
Web
It is an air-hardening secretion of the glands, consisting mainly of a protein close to silk, but much more durable.
Pedipalps
From lat. pēs - leg + palpo - stroke, feel; "leg tentacles"
Leg tentacles are the mouthparts of arachnids, used to capture and hold prey. They are longer than chelicerae.
pinocytosis
From Greek. pino - to drink; cytosis - cell
Capture and absorption by the cell of fluid and substances dissolved in it.
Planula
From the Latin word planus - flat
Hydroid larva, covered with cilia, which later attaches to underwater objects and gives rise to a new polyp.
Placenta
From lat. placenta - cake
An organ of communication between the embryo and the mother's body during fetal development in placental mammals; Through the placenta, oxygen and nutrients come from the blood of the mother's body to the embryo, and decay products and carbon dioxide are released.
fruiting body
The outer part - what we usually call the "mushroom", consists of hyphae, very tightly intertwined.
Polymorphism
From Greek. polis - numerous,
morphe - form
The presence in the composition of one species of several clearly morphologically different forms (bees, ants, termites): “queen”, “workers”, “soldiers”, etc.
population
From lat. populus - people, population
The totality of all representatives of a given species occupying a certain space at the same time.
Breed
A collection of domestic animals of the same species, artificially created by man.
Pseudopodia
Outgrowths of the cytoplasm in sarcodes are formed when necessary for movement and food capture.
Chicks
Birds whose chicks emerge from the egg helpless stay in the nest for a long time and are fed by their parents.
Regeneration
From lat. regeneration - restoration, renewal
Restoration by the body of lost or damaged body parts.
Reflex
From lat. reflexus-reflected
The response of the body to irritation, carried out through the nervous system.
Rhizoids
From Greek. riza - root, eidos - species
Outgrowths of the body serve to attach to the ground or underwater rocks (in mosses, fern growths, lichens, some algae and fungi).
Sarcins
From the Latin words sarsina - a bunch, a knot
Spherical bacteria that look like dense packs.
Segments
From lat. segmentum segment
One of many homogeneous segments of the body of some animals, as well as one of the homogeneous sections of some organ.
Core
The main tissue located in the center of the stem; performs a storage function.
Symbiosis
From Lat sim - together, bios - life
Forms of coexistence of various organisms.
Systematics
From Greek. systematically ordered
A branch of biology whose task is to describe and designate all existing and extinct organisms, as well as their classification.
Sclerotia
From Greek scleros - hard
Thickening that occurs at the site of interweaving of hyphae.
Thallus (thallus)
From Greek. thallus - sprout
The vegetative body of algae, fungi, lichens, some bryophytes, not divided into organs (leaf, stem, root) and not having real tissues.
Variety
A collection of cultivated plants of the same species, artificially created by man.
Sporangium
From Greek. spore-sowing, seed; angeion - vessel
A unicellular or multicellular asexual organ that produces spores.
sporophyte
From Greek. spore - sowing, phyton - plant
A plant that produces spores.
Spirilla
From lat spirilla-bend
Spiral bacterial cells.
statocyst
From Greek. statees-standing, cystis-bladder
Balance organ: a small vesicle of ectodermal origin with sensitive cilia and pebbles inside.
Statolith
From Greek. statos - standing, lithos - stone
Small grains of sand that fall into the statocyst and act as "earing stones".
streptococci
From Greek. streptos-chain, coccos-grain
Ball-shaped bacteria form chains of cells
(causative agents of angina, scarlet fever).
warm-blooded animals
Animals that maintain a relatively constant body temperature when the ambient temperature changes (birds, mammals).
Trachea
From Greek. tracheilos - throat
Air-breathing tubes in some invertebrates.
tracheids
From Greek. tracheilos - throat, eidos - view
Dead spindle-shaped cells with thick membranes that perform conductive and support functions.
Turgor
From lat. turgere - to be swollen, full
The elasticity of plant cells, organs due to the pressure of the contents of the cells on their elastic walls.
Phagocytosis
From Greek. phageo - devour, cytosis - cell
Absorption by the cell of large molecules of organic substances and even whole cells.
compound eyes
Compound eyes, consisting of a large number of individual small ocelli combined together.
Phycocyanin
From Greek. phycos - algae, cyanos - dark blue
Water-soluble pigment of blue color in chloroplasts of purple flowers.
Phycoerythrin
From Greek. phycos - algae, erythrin red
Water-soluble pigment of red color in chloroplasts of purple flowers.
finna
One of the larval stages of development in tapeworms. It has the appearance of a bubble, into the cavity of which one or several formed heads of worms are screwed, developing in the final host into adult worms.
Phytobenthos
From Greek. phyton - plant, benthos - depth
Bottom vegetation.
Phytoplankton
From Greek. phyton - plant, planktos - wandering
Unicellular algae in the water column.
Phytohormones
From Greek. phyton - plant, hormone - excite
Plant hormones that regulate the vital processes of the plant organism.
Phototaxis
From Greek. photos - light, taxis - location in order
Directional movement of organisms, individual cells and their organelles under the influence of light.
Chemosynthesis
from lat. chemia and Greek synthetics - connection
The process by which some microorganisms form organic substances from carbon dioxide due to the energy obtained from the oxidation of inorganic compounds.
chelicerae
From Greek. words hele - claw, claw and ceras - horn
These are the jaws - the oral organs of arachnids, serve to capture and kill prey.
Chitin
Solid and dense organic matter that is part of the external skeleton of arthropods.
Chlorella
From Greek. chloros - green
Unicellular algae.
Chlorophyll
From Greek. chloros - green, phyllon - leaf
A green pigment found in the chloroplasts of green plants.
cold-blooded animals
Animals whose body temperature changes depending on the ambient temperature (invertebrates, fish, amphibians, reptiles).
Chord
From Greek. chorde - string
The elastic skeletal axis in chordates is located under the neural tube; performs a supporting function.
Chromatophores
From Greek. chroma - color, foros - bearing
Organelles of algae that contain pigments that enable photosynthesis.
Cyst
From Greek. cystos - bladder
A temporary form of existence of many unicellular organisms, characterized by the presence of a protective shell.
Strain
German strain-tribe, genus
An artificial population of microorganisms characterized by hereditarily fixed productivity.
Evolution
From lat. evolutionary deployment
Irreversible historical process of development of living organisms.
ectoderm
From Greek. ectos - outside, derma - skin
Outer embryo sac of a multicellular animal embryo.
Embryology
from the Greek embryo-embryo and logo-teaching
Branch of biology that studies the embryonic period of development of organisms.
Endoderm
From Greek. enthos - inside, derma - skin
Inner leaf of a multicellular animal embryo.
Below is a brief dictionary of biological terms found on the pages of our site.
Without claiming to be complete, we have tried to provide our readers with accurate and extremely understandable explanations and definitions of individual biological concepts and terms. Enjoy reading!
Cell. biological unit. Plants and animals are made up of cells.
Clone. One of the organisms or cells descended from the same progenitor (that is, having the same genotype).
Rhizome. Underground part of the stem with buds.
plastida. A membrane-bound structure inside plant cells that is outside.
Floor. In many organisms (including vertebrates), sex is determined by the combination of certain chromosomes. In mammals, female cells contain XX chromosomes, while male cells contain XY chromosomes.
Polymorphism. I) The presence in a population of more than one variant of the same gene. 2) The appearance of various forms of the organism at different stages of development.
Acquired Trait. Modification of an organ during the course of an organism due to its use or non-use, as opposed to an inherited trait received from ancestors.
Bract. The leaf that covers the flower.
Recombination. The redistribution of genes or inherited traits in combinations other than those of the parents.
Recessive. A recessive gene shows its signs only if the organism received it from both parents. Recessive is a trait that is transmitted through recessive genes.
RNA, ribonucleic acid. Nucleic acid containing ribose. Carries DNA information about the structure of proteins; transports amino acids to the site of protein synthesis.
Saprophytes. Organisms that feed on organic compounds from dead bodies or animal excretions.
Symbiosis. Mutually beneficial partnership of organisms belonging to different species.
Spore. A non-sex cell that serves to procreate. Sometimes - a similar cell as part of a special formation.
About the part of the plant - soft and green, or without woody tissues in the ground part.
Stoma. A tiny hole in a leaf through which water evaporates and plants breathe.
Phosphorescence. The emission of light, usually (in animals) not accompanied by the emission of heat, as, for example, in fireflies.
A unique process for the formation of organic compounds from inorganic substances, for which the energy of sunlight is used. The main component of the process is chlorophyll.
Chloroplast. A plastid containing chlorophyll.
Chlorophyll. A green pigment in plant cells involved in the process of photosynthesis.
Chromosome. A filamentous structure contained in the nucleus of a cell, which plays an important role in cell division and the transmission of inherited traits.
Cellulose. A carbohydrate that forms the walls of plant cells.
Cytoplasm. The internal semi-liquid environment of the cell, delimited from the external environment by a membrane.
Evolution. Irreversible process of historical change of the living. Its primary basis is changes in the genotypic composition of a population over many generations.
Ecosystem. A system that includes communities of living beings and their habitat; there are nutritional bonds, energy exchange and other interrelations between the components.
Ecology. The science of the relationship of organisms with each other and with the environment.
Ethology. The science of animal behavior.
Core. The part of a cell bounded by a double membrane and containing DNA.
Ovipositor. External genital organ for laying eggs in females of many and some fish.
Biology Glossary
Abiogenesis is the development of living things from inanimate matter in the process of evolution (a hypothetical model of the origin of life).
Acarology is the science that studies ticks.
An allele is one of the specific states of a gene (dominant allele, recessive allele).
Albinism is the absence of pigmentation of the skin and its derivatives, caused by a violation of the formation of melanin pigment. The causes of albinism are different.
The aminoacial center is the active site in the ribosome where the contact between the codon and anticodon occurs.
Amitosis - direct cell division, in which there is no uniform distribution of hereditary material between daughter cells.
Amniotes are vertebrates in which a provisional organ, the amnion (water shell), is formed in embryogenesis. The development of amniotes occurs on land - in an egg, or in utero (reptiles, birds, mammals, humans).
Amniocentesis - obtaining amniotic fluid with the cells of a developing fetus in it. It is used for prenatal diagnosis of hereditary diseases and sex determination.
Anabolia (Supplement) - the appearance of new characters in the late stages of embryonic development, leading to an increase in the duration of ontogenesis.
Analogous organs - organs of animals of different taxonomic groups, similar in structure and functions performed by them, but developing from different embryonic rudiments.
Anamnia is the stage of mitosis (meiosis) in which the chromatids separate to the poles of the cell. In anaphase I of meiosis, not chromatids diverge, but gel chromosomes consisting of two chromatids, as a result of which a haploid set of chromosomes appears in each daughter cell.
Anomalies of development - a violation of the structure and function of organs in the process of individual development.
Antigens are substances of a protein nature that, when they enter the body, cause an immunological reaction with the formation of antibodies.
An anticodon is a triplet of nucleotides in a tRNA molecule that contacts an mRNA codon in the aminoacial center of the ribosome.
Antimutagens are substances of various nature that reduce the frequency of mutations (vitamins, enzymes, etc.).
Antibodies are immunoglobulin proteins produced in the body in response to the penetration of antigens.
Anthropogenesis is the evolutionary path of the origin and development of man.
Anthropogenetics is a science that studies the issues of heredity and variability in humans.
Aneuploidy - changes in the number of chromosomes in the karyotype (heteroploidy).
Arachnology is the science that studies arachnids.
Aromorphosis - evolutionary morphofunctional transformations of general biological significance that increase the level of organization of animals.
Archallaxis - changes that occur at different stages of embryonic development and guide phylogeny along a new path.
Archanthropes - a group of ancient people united in one species - homo erectus (straightened man). This species includes Pithecanthropus, Sinanthropus, Heidelberg man and other closely related forms.
Atavism is the complete development of a rudimentary organ, which is not characteristic of this species.
Autophagy is the process of digestion by a cell of its irreversibly altered organelles and cytoplasmic regions with the help of hydrolytic enzymes of lysosomes.
Twins:
Monozygotic - twins that develop from one egg fertilized by one sperm (polyembryony);
Dizygotic (polyzygotic) - twins that develop from two or more eggs fertilized by different sperm (poliovulation).
Hereditary - diseases caused by a violation of the structure and function of hereditary material. There are gene and chromosomal diseases;
Molecular - diseases caused by gene mutations. In this case, the structure of structural proteins and proteins of enzymes may change;
Chromosomal - diseases caused by a violation of the structure or number of chromosomes (autosomes or sex chromosomes) due to chromosomal or genomic mutations;
Wilson-Konovalov (hepatocerebral degeneration) is a molecular disease associated with impaired copper metabolism, which leads to damage to the liver and brain. Inherited in an autosomal recessive manner;
Galactosemia is a molecular disease associated with impaired carbohydrate metabolism. Inherited in an autosomal recessive manner;
Sickle cell anemia is a molecular disease based on a gene mutation that leads to a change in the amino acid composition of the hemoglobin B-chain. Inherited by the type of incomplete dominance;
Phenylketonuria is a molecular disease caused by a violation of the metabolism of amino acids and phenylalanine. It is inherited in an autosomal recessive manner.
Basal body (kinetosome) - Structure at the base of the flagellum, or cilia, formed by microtubules.
Biogenesis - The origin and development of organisms from living matter.
Developmental biology is a science that arose at the intersection of embryology and molecular biology and studies the structural, functional and genetic foundations of individual development, the mechanisms of regulation of the vital activity of organisms.
Blastoderm - a collection of cells (blastomeres) that form the wall of the blastula.
Brachydactyly - short fingers. It is inherited in an autosomal dominant manner.
Genetic vectors are DNA-containing structures (viruses, plasmids) used in genetic engineering to attach genes and introduce them into a cell.
Viruses are non-cellular life forms; capable of living cells and reproducing in them. They have their own genetic apparatus, represented by DNA or RNA.
Vital staining (lifetime) is a method of staining other structures with dyes that do not have a toxic effect on them.
Inclusions are non-permanent components of the cell cytoplasm, represented by secretory granules, reserve nutrients, end products of metabolism.
Degeneracy of the genetic code (redundancy) - the presence in the genetic code of several codons corresponding to one amino acid.
Gametogenesis - the process of formation of mature germ cells (gametes): female gametes - ovogenesis, male gametes - spermatogenesis.
Gametes are sex cells with a haploid set of chromosomes.
Haploid cells - cells containing a single set of chromosomes (n)
Gastrocoel is a cavity in a two- or three-layer embryo.
Gastrulation is the period of embryogenesis in which the formation of a two- or three-layer embryo is carried out.
Biohelminths - helminths, in the life cycle of which there is a change of owners or the development of all stages occurs within one organism without access to the external environment;
Geohelminths - helminths, the larval stages of which develop in the external environment (ascaris, crooked head);
Contact-transmitted - helminths, the invasive stage of which can enter the host's body upon contact with the patient (pygmy tapeworm, pinworm).
A hemizygous organism is an organism that has a single allele of the analyzed gene due to the absence of a homologous chromosome (44+XY).
Hemophilia is a molecular disease linked to the X chromosome (recessive type of inheritance). Manifested with a violation of blood clotting.
Gene - Structural unit of genetic information:
Allelic genes are genes that are localized in the same loci of homologous chromosomes and determine different manifestations of the same trait.
Non-allelic genes - localized in different loci of homologous chromosomes or in non-homologous chromosomes; determine the development of different signs;
Regulatory - controlling the work of structural genes, their function is manifested in interaction with enzyme proteins;
Structural - containing information about the polypeptide structure of the chain;
Mobile - able to move around the cell genome and take root in new chromosomes; they can change the activity of other genes;
Mosaic - eukaryotic genes, consisting of informative (exons) and non-informative (introns) sections;
Modulators - genes that enhance or weaken the action of the main genes;
Mandatory (housekeeping genes) - genes encoding proteins synthesized in all cells (histones, etc.);
Specialized ("luxury genes") - encoding proteins synthesized in individual specialized cells (globins);
Hollandic - localized in regions of the Y chromosome that are not homologous to the X chromosome; determine the development of traits inherited only through the male line;
Pseudogenes - having similar nucleotide sequences with functioning genes, but due to the accumulation of mutations in them, they are functionally inactive (they are part of the alpha and beta globin genes).
Genetics is the science of heredity and variation in organisms. The term was introduced into science in 1906. English geneticist W. Batson.
A genetic map is a conditional image of chromosomes in the form of lines with the names of genes printed on them and observing the distances between genes, expressed as a percentage of crossing over - morganids (1 morganid = 1% crossing over).
Genetic analysis is a set of methods aimed at studying the heredity and variability of organisms. It includes the hybridological method, the method of accounting for mutations, cytogenetic, population-statistical, etc.
Genetic load - the accumulation in the gene pool of a population of recessive alleles, leading in a homozygous state to a decrease in the viability of individuals and the population as a whole.
The genetic code is a system of "recording" genetic information in the form of a sequence of nucleotides in a DNA molecule.
Genetic engineering is a purposeful change in the hereditary program of a cell using the methods of molecular genetics.
Genocopies - the similarity of phenotypes that have a different genetic nature (mental retardation in some molecular diseases).
Genome - the number of genes of a haploid cell, characteristic of a given type of organism.
Genotype - a system of interacting alleles of genes characteristic of a given individual.
The gene pool is the totality of the genes of the individuals that make up the population.
Geriatrics is a branch of medicine dedicated to the development of treatments for the elderly.
Gerontology is a science that studies the processes of aging of organisms.
Geroprotectors are antimutagens that bind free radicals. Slow down the onset of old age and increase life expectancy.
Genetic heterogeneity of populations - the presence in individuals of a given population of several allelic variants (at least two) of one gene. Causes genetic polymorphism of populations.
A heterozygous organism is an organism whose somatic cells contain different alleles of a given gene.
Heteroploidy - an increase or decrease in the number of individual chromosomes in a diploid set (monosomy, trisomy).
Heterotopia is a change in the process of evolution of the place of laying in the embryogenesis of one or another organ.
Heterochromatin - sections of chromosomes that retain a spiralized state in interphase are not transcribed. Heterochrony - changes in the process of evolution of the laying time in the embryogenesis of one or another organ.
A hybrid is a heterozygous organism formed by crossing genetically different forms.
Hypertrichosis - local - a sign linked to the Y-chromosome; manifested in increased hair growth on the edge of the auricle; inherited in a recessive manner.
Embryonic histogenesis - the formation of tissues from the material of the germ layers by cell division, their growth and differentiation, migration, integration and intercellular interactions.
The hominid triad is a combination of three characteristics that are unique to humans:
Morphological: absolute upright posture, development of a relatively large brain, development of a hand adapted to subtle manipulations;
Psychosocial - abstract thinking, the second signal system (speech), conscious and purposeful labor activity.
Homozygous organism - an organism whose somatic cells contain the same alleles of a given gene.
Homoithermal animals - organisms that are able to maintain a constant body temperature regardless of the ambient temperature (warm-blooded animals, humans).
Homologous organs - organs that develop from the same embryonic rudiments; their structure may be different depending on the function performed.
Homologous chromosomes - a pair of chromosomes of the same size and structure, of which one is paternal, the other is maternal.
The gonotrophic cycle is a biological phenomenon observed in blood-sucking arthropods, in which the maturation and laying of eggs are closely associated with blood feeding.
Linkage group - a set of genes located on the same chromosome and inherited linkage. The number of linkage groups is equal to the haploid number of chromosomes. Clutch failure occurs during crossover.
Color blindness is a molecular disease linked to the X chromosome (recessive type of inheritance). Manifested by a violation of color vision.
Deviation (deviation) is the appearance of new characters at the middle stages of embryonic development, which determines a new path of phylogenesis.
Degeneration - evolutionary changes characterized by a simplification of the structure of the body compared to ancestral forms.
A deletion is a chromosomal aberration in which a portion of a chromosome falls out.
Determination is the genetically determined ability of embryonic cells only to a certain direction of differentiation.
Diakinesis is the final stage of prophase I of meiosis, during which the process of segregation of homologous chromosomes after conjugation is completed.
Divergence is the formation in the process of evolution of several new groups from a common ancestor.
A diploid cell is a cell containing a double set of chromosomes (2n).
Diplotene - stage of prophase I of meiosis - the beginning of the divergence of homologous chromosomes after conjugation.
Sex differentiation is the process of development of sexual characteristics in ontogeny.
Dominant trait - a trait that manifests itself in the homo- and heterozygous state.
A donor is an organism from which tissue or organs are taken for transplantation.
The tree of life is a schematic representation of the paths of evolutionary development in the form of a tree with branches.
Gene drift (genetic-automatic processes) - changes in the genetic structure in small populations, expressed in a decrease in genetic polymorphism and an increase in the number of homozygotes.
Cleavage is the period of embryogenesis in which the formation of a multicellular embryo occurs through successive mitotic divisions of blastomeres without increasing their size.
Duplication is a chromosomal aberration in which a portion of a chromosome is duplicated.
Natural selection is the process by which, as a result of the struggle for existence, the fittest organisms survive.
Gill arches (arterial) - blood vessels passing through the gill septa and undergoing quantitative and qualitative changes in the evolution of the circulatory system of vertebrates.
The life cycle is the time of the existence of a cell from the moment of its formation to death or division into two daughter ones as a result of the transition from the G 0 state to the mitotic cycle.
Embryonic period - in relation to a person, the period of embryogenesis from the 1st to the 8th week of intrauterine development.
The embryonic organizer is a part of the zygote (gray sickle), which largely determines the course of embryogenesis. When the gray crescent is removed, development stops at the crushing stage.
Zygotene is the prophase I stage of meiosis, in which homologous chromosomes combine (conjugate) into pairs (bivalents).
Idiodaptation (allomorphosis) - morphofunctional changes in organisms that do not increase the level of organization, but make this species adapted to specific living conditions.
Variability - the property of organisms to change in the process of individual development of individual signs:
Modification - phenotypic changes due to the influence of environmental factors on the genotype;
Genotypic - variability associated with quantitative and qualitative changes in the hereditary material;
Combinative - a type of variability that depends on the recombination of genes and chromosomes in the genotype (meiosis and fertilization);
Mutational - a type of variability associated with a violation of the structure and function of the hereditary material (mutations).
Immunosuppression - suppression of protective immunological reactions of the body.
Immunosuppressants are substances that suppress the response of the immune system of the recipient's body to the transplant, helping to overcome tissue incompatibility and engraftment of the transplanted tissue.
Inversion is a chromosomal aberration in which intrachromosomal breaks occur and the excised area is flipped 180 0 .
Embryonic induction is the interaction between parts of the embryo, during which one part (inductor) determines the direction of development (differentiation) of the other part.
Initiation is a process that ensures the start of matrix synthesis reactions (translation initiation is the binding of the AUG codon to tRNA-methionine in the peptide center of the small subunit of the ribosome of the ribosome).
Inoculation - the introduction of the pathogen by the carrier into the wound with saliva in the bite.
Interphase is the part of the cell cycle during which the cell prepares for division.
An intron is an uninformative region of a mosaic gene in eukaryotes.
Karyotype is a diploid set of somatic cells, characterized by the number of chromosomes, their structure and size. species-specific trait.
Housing is a form of symbiosis in which one organism uses the other as a home.
Keylons are substances of a protein nature that inhibit the mitotic activity of cells. Kinetoplast is a specialized part of the mitochondria that provides energy for the movement of the flagellum.
The kinetochore is a specialized region of the centromere, in the region of which the formation of short microtubules of the division spindle and the formation of connections between chromosomes and centrioles occurs.
Classification of chromosomes:
Denever - chromosomes are combined into groups based on their size and shape. To identify chromosomes, a continuous staining method is used;
Parisian - based on the characteristics of the internal structure of chromosomes, which is detected using differential staining. The same arrangement of segments is present only in homologous chromosomes.
Gene clusters are groups of different genes with related functions (globin genes).
A clone of cells is a collection of cells formed from one parent cell by successive mitotic divisions.
Cloning of genes - obtaining a large number of homogeneous DNA fragments (genes).
Codominance is a type of interaction of allelic genes (in the presence of many alleles), when two dominant genes appear in the phenotype independently of each other (IV blood group).
A codon is a sequence of three nucleotides in a DNA molecule (mRNA) corresponding to an amino acid (sense codon). In addition to sense codons, there are termination and initiation codons.
Collinearity is the correspondence of the order of nucleotides in a DNA molecule (mRNA) to the order of amino acids in a protein molecule.
Colchicine is a substance that destroys spindle microtubules and stops mitosis at the metaphase stage.
Commensalism is a form of symbiosis that benefits only one organism.
Complementarity - strict correspondence of nitrogenous bases to each other (A-T; G-C)
The type of interaction of non-allelic genes, when the development of a trait is determined by two pairs of genes.
Counseling (medical-genetic) - counseling the applicant about the possible inheritance of a particular disease and how to prevent it using the method of genetic analysis.
Contamination is a method of infection with the help of a carrier, in which the pathogen enters the body through microtraumas on the skin and mucous membranes or orally with contaminated products.
Conjugation - conjugation in bacteria - a process in which microorganisms exchange plasmids, in connection with which cells acquire new properties:
Conjugation in ciliates is a special type of sexual process in which two individuals exchange haploid migratory nuclei;
Chromosome conjugation is the joining of homologous chromosomes into pairs (bivalents) in prophase I of meiosis.
Copulation is the process of fusion of germ cells (individuals) in protozoa.
Correlations - interdependent, coupled development of certain structures of the body:
Ontogenetic - the consistency of the development of individual organs and systems in individual development;
Phylogenetic (coordination) - stable interdependencies between organs or parts of the body, determined phylogenetically (combined development of teeth, length of intestines in carnivores and herbivores).
Crossing over is the exchange of sections of chromatids of homologous chromosomes, which occurs in the prophase I of meiosis and leads to the recombination of genetic material.
Cultivation of cells, tissues is a method that allows preserving the viability of structures when they are grown on artificial nutrient media outside the body to study the processes of proliferation, growth, and differentiation.
Leptotene is the initial stage of prophase I of meiosis, in which the chromosomes in the cell nucleus are visible in the form of thin threads.
Lethal equivalent - a coefficient that allows you to quantify the genetic load of the population. In humans, the equivalent is 3-8 recessive homozygous states, leading the body to death before the reproductive period.
Ligases are enzymes that connect (“cross-link”) individual fragments of nucleic acid molecules into a single whole (joining exons during splicing).
Macroevolution - evolutionary processes occurring in taxonomic units above the species level (order, class, type).
Marginotomy hypothesis - a hypothesis that explains the aging process by a decrease in the DNA molecule by 1% after each cell division (shorter DNA - shorter life).
Mesonerphosis (primary kidney) is a type of vertebrate kidney, in which the structural and functional elements are the Bowman-Shumlyansky capsules beginning to form, associated with capillary glomeruli. It is laid in the trunk department.
Meiosis is the division of oocytes (spermatocytes) during maturation (gametogenesis). The result of meiosis is the recombination of genes and the formation of haploid cells.
Metagenesis is the alternation in the life cycle of organisms of sexual and asexual reproduction.
Metanephros (secondary kidney) is a type of vertebrate kidney, the structural and functional element of which is the nephron, which consists of specialized departments. Laid in the phase department.
Metaphase - the stage of mitosis (meiosis), in which the maximum spiralization of chromosomes located along the equator of the cell is achieved, and the mitotic apparatus is formed.
Genetic methods:
Twin - a method of studying twins by establishing intra-pair similarity (concordance) and differences (discordance) between them. Allows you to determine the relative role of heredity and the environment for the development of traits in a descendant;
Genealogical - a method of compiling pedigrees; allows you to establish the type of inheritance and predict the probability of inheritance of traits in descendants;
Hybridization of somatic cells is an experimental method that allows the fusion of somatic cells of various organisms in culture to obtain combined karyotypes;
Hybridological - a method that establishes the nature of the inheritance of traits using a system of crosses. It consists in obtaining hybrids, their analysis in a number of generations using quantitative data;
Modeling of hereditary diseases - the method is based on the law of homologous series of hereditary variability. Allows the use of experimental data obtained on animals for the study of human hereditary diseases;
Ontogenetic (biochemical) - the method is based on the use of biochemical methods to identify metabolic disorders caused by an abnormal gene in the individual development;
Population-statistical - the method is based on the study of the genetic composition of populations (Hardy-Weinberg law). Allows you to analyze the number of individual genes and the ratio of genotypes in the population;
Cytogenetic - a method of microscopic study of the hereditary structures of the cell. Used in karyotyping and determination of sex chromatin.
Microevolution - elementary evolutionary processes occurring at the population level.
Mitotic (cellular) cycle - the time of existence of the cell in the period of preparation for mitosis (G 1, S, G 2) and the mitosis itself. The period G 0 is not included in the duration of the mitotic cycle.
Mimicry is a biological phenomenon expressed in the imitative similarity of unprotected organisms to unrelated protected or inedible species.
Mitosis is a universal method of somatic cell division, in which there is a uniform distribution of genetic material between two daughter cells.
The mitotic apparatus is a division apparatus formed in metaphase and consisting of centrioles, microtubules and chromosomes.
mRNA modification is the final processing step that occurs after splicing. Modification of the 5'-end occurs by attaching a cap structure represented by methylguanine, and a polyadenine "tail" is attached to the 3'-end.
Sauropsid - a type of brain of vertebrates, in which the leading role belongs to the forebrain, where clusters of nerve cells in the form of islands first appear - the ancient cortex (reptiles, birds);
Ichthyopsid - type of vertebrate brain, in which the leading role belongs to the midbrain (cyclostomes, fish, amphibians);
Mammal - a type of vertebrate brain, in which the integrating function is performed by the cerebral cortex, which completely covers the forebrain - the new cortex (mammals, humans).
Genetic monitoring is an information system for registering the number of mutations in populations and comparing mutation rates over a number of generations.
A monomer is a structural element (block) of a polymer chain (in a protein it is an amino acid, in DNA it is a nucleotide).
autolysis, autolysis, self-digestion of tissues, cells or their parts under the action of enzymes in animals, plants and microorganisms.
autotrophic organisms, autotrophs, organisms that use carbon dioxide as the sole or main source of carbon to build their body and have both an enzyme system for carbon dioxide assimilation and the ability to synthesize all cell components. Autotrophic organisms include terrestrial green plants, algae, phototrophic bacteria capable of photosynthesis, as well as some bacteria that use the oxidation of inorganic substances - chemoautotrophs.
adenosine diphosphate, ADP, a nucleotide consisting of adenine, ribose, and two phosphoric acid residues. Being a phosphoryl group acceptor in the processes of oxidative and photosynthetic phosphorylation, as well as phosphorylation at the substrate level and a biochemical precursor of ATP - a universal energy accumulator, adenosine diphosphate plays an important role in the energy of a living cell.
adenosine monophosphate, AMP, adenylic acid, a nucleotide consisting of adenine, ribose and one phosphoric acid residue. In the body, adenine monophosphate is found in the composition of RNA, coenzymes and in free form.
adenosine triphosphate, ATP, adenylpyrophosphoric acid, a nucleotide containing adenine, ribose, and three phosphoric acid residues; universal carrier and main accumulator of chemical energy in living cells, released during the transfer of electrons in the respiratory chain after the oxidative breakdown of organic substances.
Aleurone grains(from the Greek aleuron - flour), grains of storage protein in the cells of the storage tissues of seeds of legumes, buckwheat, cereals and other plants. They occur as amorphous or crystalline deposits (from 0.2 to 20 microns) of various shapes and structures. They are formed during seed maturation from drying vacuoles and are surrounded by an elementary tonoplast membrane. Large complex aleurone grains consist of a protein crystalloid and a non-protein part (phytin), some of them contain calcium oxalate crystals. During seed germination, aleurone grains swell and undergo enzymatic cleavage, the products of which are used by the growing parts of the embryo.
allele(from the Greek allelon - each other, mutually), allelomorph, one of the possible structural states of a gene. Any change in the structure of a gene as a result of mutations or due to intragenic recombinations in heterozygotes for two mutant alleles leads to the appearance of new alleles of this gene (the number of alleles of each gene is practically incalculable). The term "allele" was proposed by W. Johansen (1909). Different alleles of the same gene can lead to the same or different phenotypic effects, which was the basis for the concept of multiple allelism.
Amyloplasts(from the Greek amylon - starch and plastos - molded), plastids (from the group of leukoplasts) of a plant cell that synthesize and accumulate starch.
amino acids, organic (carboxylic) acids containing, as a rule, one or two amino groups (-NH 2). About twenty amino acids are usually involved in the construction of protein molecules. The specific sequence of alternation of amino acids in peptide chains, determined by the genetic code, determines the primary structure of the protein.
Amitosis, direct division of the interphase nucleus by constriction without the formation of chromosomes, outside the mitotic cycle. Amitosis can be accompanied by cell division, as well as limited to nuclear division without division of the cytoplasm, which leads to the formation of bi- and multinuclear cells. Amitosis occurs in various tissues, in specialized cells doomed to death.
Anabolism(from the Greek anabole - rise), assimilation, a set of chemical processes in a living organism aimed at the formation and renewal of the structural parts of cells and tissues. Opposite to catabolism (dissimilation), it consists in the synthesis of complex molecules from simpler ones with the accumulation of energy. The energy required for biosynthesis (mainly in the form of ATP) is supplied by catabolic reactions of biological oxidation. Very intense anabolism occurs during the growth period: in animals - at a young age, in plants - during the growing season. The most important process of anabolism, which has planetary significance, is photosynthesis.
Anticodon, a section of a transfer RNA molecule, consisting of three nucleotides and recognizing the corresponding section of three nucleotides (codon) in the messenger RNA molecule, with which it complementarily interacts. The specific codon-anticodon interaction that occurs on ribosomes during translation ensures the correct arrangement of amino acids in the synthesized polypeptide chain.
outbreeding(from English out - outside and breeding - breeding), crossing or a system of crossing unrelated forms of the same species. On the basis of outbreeding, heterotic forms are obtained by carrying out interline and interbreed (intervarietal) crosses. Outbreeding is the opposite of inbreeding.
autosomes, all chromosomes in the cells of dioecious animals, plants and fungi, with the exception of sex chromosomes.
acidophilia, the ability of cellular structures to stain with acidic dyes (eosomine, acid fuchsin, picric acid, etc.) due to the basic (alkaline) properties of staining structures.
aerobic organisms, aerobes (from the Greek aer - air and bios - life), organisms that can live and develop only in the presence of free oxygen in the environment, which they use as an oxidizing agent. Aerobic organisms include all plants, most protozoa and multicellular animals, almost all fungi, i.e. the vast majority of known species of living beings.
basal body, kinetosome (corpusculum basale), an intracellular eukaryotic structure that lies at the base of cilia and flagella and serves as a support for them. The ultrastructure of the basal bodies is similar to that of the centrioles.
Basophilia, the ability of cellular structures to stain with basic (alkaline) dyes (azure, pyronin, etc.), due to the acidic properties of the staining components of the cell, mainly RNA. An increase in cell basophilia usually indicates an intensive protein synthesis taking place in it. Basophilia is characteristic of growing, regenerating, tumor tissues.
basophils, cells containing granular structures in protoplasm stained with basic dyes. The term "basophils" refers to one of the types of granular leukocytes (granulocytes) of the blood (normally, basophils in humans make up 0.5-1% of all leukocytes), as well as one of the types of cells of the anterior pituitary gland.
Backcross(from English back - back, back and cross - crossing), backcrossing, crossing a hybrid of the first generation with one of the parental forms or a form similar to it in genotype.
Squirrels, proteins, high molecular weight organic compounds built from amino acid residues. They play a primary role in life, performing numerous functions in their structure, development and metabolism. The molecular weight of proteins is from about 5000 to many millions. The infinite variety of protein molecules (as a rule, 20 a-L-amino acids are included in proteins) due to the different sequence of amino acid residues and the length of the polypeptide chain determines the differences in their spatial structure, chemical and physical properties. Depending on the shape of the protein molecule, fibrillar and globular proteins are distinguished, from the function they perform - structural, catalytic (enzymes), transport (hemoglobin, ceruloplasmin), regulatory (some hormones), protective (antibodies, toxins), etc .; from the composition - simple proteins (proteins, consist only of amino acids) and complex (proteins, which, along with amino acids, include carbohydrates - glycoproteins, lipids - lipoproteins, nucleic acids - nucleoproteins, metals - metalloproteins, etc.); depending on solubility in water, solutions of neutral salts, alkalis, acids and organic solvents - albumins, globulins, glutelins, histones, protamines, prolamins. The biological activity of proteins is due to their unusually flexible, plastic and at the same time strictly ordered structure, which makes it possible to solve the problems of recognition at the molecular level, as well as to exercise subtle regulatory influences. There are the following levels of structural organization of proteins: primary structure (sequence of amino acid residues in the polypeptide chain); secondary (folding of the polypeptide chain into a-helical sections and structural formations); tertiary (three-dimensional spatial packing of the polypeptide chain) and quaternary (association of several separate polypeptide chains into a single structure). The primary structure of the protein is the most stable, the rest are easily destroyed by an increase in temperature, a sharp change in the pH of the medium, and other influences. Such a violation is called denaturation and, as a rule, is accompanied by a loss of biological properties. The primary structure of the protein determines the secondary and tertiary, i.e. self-assembly of a protein molecule. Proteins in the cells of organisms are constantly updated. The need for their constant renewal underlies the metabolism. The decisive role in protein biosynthesis belongs to nucleic acids. Proteins are the primary products of genes. The amino acid sequence in proteins reflects the nucleotide sequence in nucleic acids.
Bivalent(from the Latin bi-, in compound words - double, double and valent - strong), a pair of homologous chromosomes connected (conjugating) to each other in meiosis. It is formed at the zygotene stage and persists until the anaphase of the first division. In the bivalent, X-shaped figures are formed between the chromosomes - chiasmata, which hold the chromosomes in the complex. The number of bivalents is usually equal to the haploid number of chromosomes.
Bio…(from the Greek bios - life), part of compound words, corresponding in meaning to the words "life", "living organism" (biography, hydrobios) or the word "biological" (biocatalysis, biophysics).
biogenetic law, a generalization in the field of the relationship between ontogenesis and phylogenesis of organisms, established by F. Müller (1864) and formulated by E. Haeckel (1866): the ontogeny of any organism is a brief and concise repetition (recapitulation) of the phylogenesis of a given species.
Biogenic elements, chemical elements that are constantly included in the composition of organisms and necessary for them to live. In living cells, traces of almost all chemical elements present in the environment are usually found, but about 20 are necessary for life. The most important biogenic elements are oxygen (about 70% of the mass of organisms), carbon (18%), hydrogen (10%), nitrogen , potassium, calcium, phosphorus, magnesium, sulfur, chlorine, sodium. These so-called universal biogenic elements are present in the cells of all organisms. Some biogenic elements are important only for certain groups of living beings (for example, boron and other biogenic elements are necessary for plants, vanadium for ascidians, etc.).
biological membranes(Latin membrana - skin, shell, membrane), structures that limit cells (cellular or plasma membranes) and intracellular organelles (membranes of mitochondria, chloroplasts, lysosomes, endoplasmic reticulum, etc.). They contain lipids, proteins, heterogeneous macromolecules (glycoproteins, glycolipids) and, depending on the function performed, numerous minor components (coenzymes, nucleic acids, amino acids, carotenoids, inorganic ions, etc.). The main functions of biological membranes are barrier, transport, regulatory and catalytic.
Fermentation, anaerobic enzymatic redox process of transformation of organic substances, through which organisms obtain the energy necessary for life. Compared to processes taking place in the presence of oxygen, fermentation is an evolutionarily earlier and energetically less favorable form of extracting energy from nutrients. Animals, plants and many microorganisms are capable of fermentation (some bacteria, microscopic fungi, protozoa grow only due to the energy obtained during fermentation).
Vacuoles(French vacuole from Latin vacuus - empty), cavities in the cytoplasm of animal and plant cells, bounded by a membrane and filled with liquid. In the cytoplasm of protozoa, there are digestive vacuoles containing enzymes and contractile vacuoles that perform the functions of osmoregulation and excretion. Multicellular animals are characterized by digestive and autophagic vacuoles, which are part of the group of secondary lysosomes and contain hydrolytic enzymes.
In plants, vacuoles are derivatives of the endoplasmic reticulum and are surrounded by a semi-permeable membrane - the tonoplast. The entire system of vacuoles of a plant cell is called a vacuum, which in a young cell is represented by a system of tubules and vesicles; as the cell grows and differentiates, they increase and merge into one large central vacuole, which occupies 70-95% of the volume of a mature cell. Vacuole cell sap is an aqueous liquid with a pH of 2-5, contains organic and inorganic salts (phosphates, oxalates, etc.) dissolved in water, sugars, amino acids, proteins, end or toxic metabolic products (tannins, glycosides, alkaloids) some pigments (for example, anthocyanins). Functions of vacuoles: regulation of water-salt metabolism, maintenance of turgor pressure in the cell, accumulation of low-molecular water-soluble metabolites, reserve substances and elimination of toxic substances from metabolism.
Spindle of division, achromatin spindle, a system of microtubules in a dividing cell, which ensures the divergence of chromosomes in mitosis and meiosis. The spindle is formed in prometaphase and disintegrates in telophase.
Cell inclusions, components of the cytoplasm, which are deposits of substances temporarily removed from metabolism or its final products. The specificity of cell inclusions is associated with the specialization of the corresponding cells, tissues and organs. The most common trophic inclusions of cells are drops of fat, clumps of glycogen, yolk in eggs. In plant inclusion cells, the cells are mainly represented by starch and aleurone grains and lipid droplets. Cell inclusions also include secretory granules in the glandular cells of animals, crystals of some salts (mainly calcium oxalates) in plant cells. A special type of cell inclusions - residual bodies - products of the activity of lysosomes.
gas exchange, a set of processes of gas exchange between the body and the environment; consists in the consumption of oxygen by the body, the release of carbon dioxide, a small amount of other gaseous substances and water vapor. The biological significance of gas exchange is determined by its direct participation in metabolism, the conversion of the chemical energy of digested nutrient products into the energy necessary for the life of the organism.
Gamete(from the Greek gamete - wife, gametes - husband), sex cell, reproductive cell of animals and plants. The gamete ensures the transmission of hereditary information from parents to offspring. The gamete has a haploid set of chromosomes, which is provided by a complex process of gametogenesis. Two gametes, merging during fertilization, form a zygote with a diploid set of chromosomes, which gives rise to a new organism.
Gametogenesis development of sex cells (gametes).
gametophyte, sexual generation in the life cycle of plants developing with alternation of generations. It is formed from a spore, has a haploid set of chromosomes; produces gametes either in ordinary vegetative cells of the thallus (some algae) or in specialized organs of sexual reproduction - gametangia, oogonia and antheridia (lower plants), archegonia and antheridia (higher plants with the exception of flowering plants).
Haploid(from the Greek haplos - single, simple and eidos - view), an organism (cell, nucleus) with a single (haploid) set of chromosomes, which is denoted by the Latin letter n. In many eukaryotic microorganisms and lower plants, the haploid normally represents one of the stages of the life cycle (haplophase, gametophyte), and in some species of arthropods, males are haploid, developing from unfertilized or fertilized eggs, but in which one of the haploid sets of chromosomes is eliminated. In most animals (and humans) only germ cells are haploid.
Haplont(from the Greek haplos - single, simple and on - being), an organism in which all cells contain a haploid set of chromosomes, and only the zygote is diploid. Some protozoa (eg coccidia), fungi (oomycetes), many green algae.
hemicelluloses, a group of polysaccharides of higher plants that, together with cellulose, make up the cell wall.
Gene(from the Greek genos - genus, origin), hereditary factor, functionally indivisible unit of genetic material; a section of a DNA molecule (in some viruses, RNA) that encodes the primary structure of a polypeptide, transport and ribosomal RNA molecules, or interacts with a regulatory protein. The totality of the genes of a given cell or organism makes up its genotype. The existence of hereditary discrete factors in germ cells was hypothetically postulated by G. Mendel in 1865 and in 1909. V. Johansen called them genes. Further ideas about genes are associated with the development of the chromosome theory of heredity.
…genesis(from the Greek genesis - origin, occurrence), part of compound words meaning origin, the process of formation, for example, ontogenesis, oogenesis.
genetic information, information about the properties of the organism, which is inherited. Genetic information is recorded by the sequence of nucleotides of nucleic acid molecules (DNA, in some viruses also RNA). Contains information about the structure of all (about 10,000) enzymes, structural proteins and RNA of the cell, as well as the regulation of their synthesis. Various enzymatic complexes of the cell read the genetic information.
Genetic map of the chromosome, scheme of mutual arrangement of genes in the same linkage group. To compile a genetic map of chromosomes, it is necessary to identify many mutant genes and carry out numerous crosses. The distance between genes on the genetic map of chromosomes is determined by the frequency of crossing over between them. The distance unit on the genetic map of the chromosomes of meiotically dividing cells is the morganide, which corresponds to 1% crossing over.
Genetic code, a unified system for recording hereditary information in nucleic acid molecules in the form of a sequence of nucleotides, characteristic of living organisms; determines the sequence of inclusion of amino acids in the synthesized polypeptide chain in accordance with the nucleotide sequence of the gene. Implementation of the genetic code in living cells, i.e. the synthesis of the protein encoded by the gene is carried out using two matrix processes - transcription and translation. General properties of the genetic code: triplet (each amino acid is encoded by a triple of nucleotides); non-overlapping (codons of one gene do not overlap); degeneracy (many amino acid residues are encoded by several codons); uniqueness (each individual codon encodes only one amino acid residue); compactness (there are no “commas” between codons and mRNA - nucleotides that are not included in the codon sequence of a given gene); universality (the genetic code is the same for all living organisms).
genetic material, cell components, the structural and functional unity of which ensures the storage, implementation and transmission of hereditary information during vegetative and sexual reproduction.
Genome(German Genom), a set of genes characteristic of the haploid set of chromosomes of a given type of organism; main haploid set of chromosomes.
Genotype, the genetic (hereditary) constitution of an organism, the totality of all hereditary inclinations of a given cell or organism, including alleles of genes, the nature of their physical linkage in chromosomes and the presence of chromosome structures.
gene pool, the totality of genes that individuals of a given population, group of populations or species have.
Heterogamy, 1) the type of sexual process, male and female gametes that merge during fertilization are different in shape and size. For higher plants and multicellular animals, as well as for some fungi, oogamy is characteristic; according to the ratio of individuals of a number of protozoa that copulate and conjugate during the sexual process, the term "anisogamy" is used. 2) Change in the function of male and female flowers or their location on the plant (as an anomaly).
heterozygote, an organism (cell) in which homologous chromosomes carry different alleles (alternative forms) of a particular gene. Heterozygosity, as a rule, determines the high viability of organisms, their good adaptability to changing environmental conditions, and therefore is widespread in natural populations.
heterotrophic organisms, heterotrophs, organisms that use exogenous organic matter as a source of carbon. As a rule, these same substances serve for them at the same time as a source of energy (organotrophy). Heterotrophic organisms, as opposed to autotrophic organisms, include all animals, fungi, most bacteria, as well as chlorophyll-free land plants and algae.
Heterochromatin, areas of chromatin that are in a condensed (densely packed) state throughout the entire cell cycle. They are intensely stained with nuclear dyes and are clearly visible under a light microscope even during interphase. Heterochromatic regions of chromosomes, as a rule, replicate later than euchromatic regions and are not transcribed; genetically very inert.
Hyaloplasm, the main plasma, the matrix of the cytoplasm, a complex colorless colloidal system in the cell, capable of reversible transitions from sol to gel.
Glycogen, a branched polysaccharide whose molecules are built from a-D-glucose residues. Molecular weight 10 5 -10 7 . The rapidly mobilized energy reserve of many living organisms accumulates in vertebrates mainly in the liver and muscles.
Glycocalyx(from Greek glykys - sweet and Latin callum - thick skin), a glycoprotein complex associated with the outer surface of the plasma membrane in animal cells. Thickness - several tens of nanometers. In the glycocalyx, extracellular digestion occurs, many cell receptors are located in it, and with its help, apparently, cell adhesion occurs.
glycolysis, the Embden-Meyerhof-Parnassus pathway, an enzymatic anaerobic process of non-hydrolytic breakdown of carbohydrates (mainly glucose) to lactic acid. It provides the cell with energy in conditions of insufficient oxygen supply (in obligate anaerobes, glycolysis is the only process that supplies energy), and under aerobic conditions, glycolysis is the stage preceding respiration - the oxidative breakdown of carbohydrates to carbon dioxide and water.
glycolipids, lipids containing a carbohydrate moiety. They are present in the tissues of plants and animals, as well as in some microorganisms. Glycosphingolipids and glycophospholipids are part of biological membranes, play an important role in the phenomena of intercellular adhesion, and have immune properties.
Glycoproteins, glycoproteins, complex proteins containing carbohydrates (from fractions of a percent to 80%). Molecular weight from 15,000 to 1,000,000. Present in all tissues of animals, plants and microorganisms. Glycoproteins, which are part of the cell membrane, are involved in cell ion exchange, immunological reactions, tissue differentiation, intercellular adhesion phenomena, etc.
globular proteins, proteins whose polypeptide chains are folded into compact spherical or elliptical structures (globules). The most important representatives of globular proteins are albumins, globulins, protamines, histones, prolamins, glutelins. Unlike fibrillar proteins, which mainly play a supporting or protective role in the body, many globular proteins perform dynamic functions. Globular proteins include almost all known enzymes, antibodies, some hormones, and many transport proteins.
Glucose, grape sugar, one of the most common monosaccharides of the hexose group, the most important source of energy in living cells.
Homogamety, a characteristic of an organism (or group of organisms) that has a pair or several pairs of homologous sex chromosomes in the chromosome set and, as a result, form gametes that are identical in the set of chromosomes. The sex represented by such individuals is called homogametic. In mammals, fish and some plant species (hemp, hops, sorrel), homogamety is characteristic of the female, and in birds, butterflies and some types of strawberries - for the male.
Homozygote, a diploid or polyploid cell (individual), whose homologous chromosomes carry identical alleles of a particular gene.
homologous chromosomes, contain the same set of genes, are similar in morphological features, conjugate in the prophase of meiosis. In a diploid set of chromosomes, each pair of chromosomes is represented by two homologous chromosomes, which can differ in the alleles of the genes they contain and exchange sites in the process of crossing over.
Gram-positive bacteria prokaryotes whose cells stain positively according to the Gram method (they are able to bind the main dyes - methylene blue, gentian violet, etc., and after treatment with iodine, then alcohol or acetone, retain the iodine-dye complex). In modern literature, gram-positive bacteria include bacteria of the Firmicutes department with the so-called gram-positive type of cell wall structure. Gram-positive bacteria are characterized by: sensitivity to certain antibiotics (not acting on gram-negative bacteria), some features of the composition and structure of the membrane apparatus, the composition of ribosomal proteins, RNA polymerase, the ability to form endospores, true mycelium, and other properties.
deoxyribonucleic acids, DNA, nucleic acids containing deoxyribose as a carbohydrate component, and adenine (A), guanine (G), cytosine (C), thymine (T) as nitrogen bases. They are present in the cells of any organism, and are also part of the DNA molecule. The sequence of nucleotides in an unbranched polynucleotide chain is strictly individual and specific for each natural DNA and represents a code form for recording biological information (genetic code).
Division, a form of reproduction of some organisms and many cells that make up the body of multicellular organisms.
Denaturation(from the Latin de- prefix, meaning removal, loss, and natura - natural properties), the loss of the natural (native) configuration of molecules of proteins, nucleic acids and other biopolymers as a result of heating, chemical treatment, etc. due to the rupture of non-covalent (weak) bonds in biopolymer molecules (weak bonds maintain the spatial structure of biopolymers). Usually accompanied by a loss of biological activity - enzymatic, hormonal, etc. It can be complete and partial, reversible and irreversible. Denaturation does not violate strong covalent chemical bonds, but due to the unfolding of the globular structure, it makes the radicals inside the molecule accessible to solvents and chemical reagents. In particular, denaturation facilitates the action of proteolytic enzymes, giving them access to all parts of the protein molecule. The reverse process is called renaturation.
differentiation, the emergence of differences between homogeneous cells and tissues, their changes in the course of the development of an individual, leading to the formation of specialized cells, organs and tissues.
Idioblasts(from the Greek idios - special, peculiar), single cells included in a tissue and differing from the cells of this tissue in size, function, shape or internal contents, for example, cells with calcium oxalate crystals or thick-walled supporting cells in the leaf parenchyma (sclereids ).
Idiogram(from the Greek idios - special, peculiar and gramma - drawing, line) a kind of generalized image of the karyotype in compliance with the average quantitative relationships between individual chromosomes and their parts. The idiogram depicts not only the morphological features of chromosomes, but also the features of their primary structure, spiralization, heterochromatin regions, etc. Comparative analysis of the idiogram is used in karyosystematics to identify and assess the degree of relatedness of various groups of organisms based on the similarity and difference of their chromosome sets.
isogamy, a type of sexual process in which confluent (copulating) gametes do not differ morphologically, but have different biochemical and physiological properties. Isogamy is widespread in unicellular algae, lower fungi, and many protozoa (radiolarian rhizomes, lower gregarines), but is absent in multicellular organisms.
Interphase(from Latin inter - between and Greek phasis - appearance), in dividing cells part of the cell cycle between two successive mitoses; in cells that have lost the ability to divide (for example, neurons), the period from the last mitosis to cell death. Interphase also includes the temporary exit of the cell from the cycle (resting state). Synthetic processes take place in the interphase, which are associated both with the preparation of cells for division and ensure cell differentiation and the performance of specific tissue functions. The duration of interphase, as a rule, is up to 90% of the time of the entire cell cycle. A distinctive feature of interphase cells is the despiralized state of chromatin (an exception is the polytene chromosomes of Diptera and some plants, which persist throughout the entire interphase).
Intron(English intron, from intervening sequence - literally an intermediate sequence), a section of a gene (DNA) of eukaryotes, which, as a rule, does not carry genetic information related to the synthesis of the protein encoded by this gene; located between other fragments of the structural gene - exons. The regions corresponding to the intron are present, along with exons, only in the primary transcript, the mRNA precursor (pro-mRNA). They are removed from it by special enzymes during mRNA maturation (exons remain). A structural gene can contain up to several tens of introns (for example, there are 50 of them in the chicken collagen gene) or not contain them at all.
ion channels, supramolecular systems of membranes of a living cell and its organelles, which are of a lipoprotein nature and ensure the selective passage of various ions through the membrane. The most common channels for Na + , K + , Ca 2+ ions; Often, proton-conducting systems of bioenergetic complexes are also referred to as ion channels.
ion pumps, molecular structures built into biological membranes and carrying out the transfer of ions towards a higher electrochemical potential (active transport); function due to the energy of ATP hydrolysis or the energy released during the transfer of electrons through the respiratory chain. Active transport of ions underlies the bioenergetics of the cell, the processes of cellular excitation, absorption, as well as the removal of substances from the cell and the body as a whole.
Karyogamy, the fusion of the nuclei of male and female germ cells in the nucleus of the zygote during fertilization. In the course of karyogamy, the pairing of homologous chromosomes is restored, carrying genetic information from the maternal and paternal gametes.
Mitosis(from karyo-kernel and Greek kinesis - movement), division of the cell nucleus.
Kariology, a section of cytology that studies the cell nucleus, its evolution and individual structures, including sets of chromosomes in different cells - karyotypes (nucleus cytology). Kariology arose in the late 19th and early 20th centuries. after establishing the leading role of the cell nucleus in heredity. The possibility of establishing the degree of relationship between organisms by comparing their karyotypes determined the development of karyosystematics.
Karyoplasm, karyolymph, nuclear juice, the contents of the cell nucleus, in which chromate is immersed, as well as various intranuclear granules. After extraction of chromatin with chemical agents, the so-called intranuclear matrix is preserved in the karyoplasm, consisting of protein fibrils 2-3 nm thick, which form a framework in the nucleus that connects the nucleoli, chromatin, pore complexes of the nuclear membrane and other structures.
Karyosystematics, a branch of systematics that studies the structure of the cell nucleus in different groups of organisms. Karyosystematics developed at the intersection of systematics with cytology and genetics and usually studies the structure and evolution of the chromosome set - the karyotype.
Karyotype, a set of features of a chromosome set (number, size, shape of chromosomes) characteristic of a particular species. The constancy of the karyotype of each species is maintained by the laws of mitosis and meiosis. Changes in the karyotype can occur due to chromosomal and genomic mutations. Usually, the description of the chromosome set is made at the stage of metaphase or late prophase and is accompanied by counting the number of chromosomes, morphs.
