BIOLOGY dictionary

 

This are some list of words you need to know as a biology student

aerobic

(of an organism or process) depending on oxygen

agglutination

proteinaceous particles, such as blood cells and bacteria, that form clumps in antibody–antigen reactions

albino

a person with congenital absence of pigmentation in the skin, eyes, and hair

allele or allelomorph

any of two or more variants of a gene that have the same relative position on homologous chromosomes and are responsible for alternative characteristics, such as smooth or wrinkled seeds in peas

anaerobic

(of an organism or process) requiring the absence of or not dependent on the presence of oxygen

anterior

of or near the head end

asexual

not involving the fusion of male and female gametes, as in vegetative reproduction, fission, or budding

assimilation

the change of digested food into the protoplasm of an animal; also, the absorption and incorporation of nutritive elements by plants, as in photosynthesis

bacteria

a very large group of microorganisms comprising one of the three domains of living organisms. They are prokaryotic, unicellular, and either free-living in soil or water or parasites of plants or animals

binary fission

asexual reproduction in unicellular organisms by division into two daughter cells

biomass

the total number of living organisms in a given area, expressed in terms of living or dry weight per unit area

blood

a reddish fluid in vertebrates that is pumped by the heart through the arteries and veins, supplies tissues with nutrients, oxygen, etc, and removes waste products. It consists of a fluid (see blood plasma) containing cells (erythrocytes, leucocytes, and platelets)

blood vessel

an artery, capillary, or vein

bone

any of the various structures that make up the skeleton in most vertebrates

cell

the basic structural and functional unit of living organisms. It consists of a nucleus, containing the genetic material, surrounded by the cytoplasm in which are mitochondria, lysosomes, ribosomes, and other organelles. All cells are bounded by a cell membrane; plant cells have an outer cell wall in addition

chromosome

any of the microscopic rod-shaped structures that appear in a cell nucleus during cell division, consisting of nucleoprotein arranged into units (genes) that are responsible for the transmission of hereditary characteristics

circulation

the transport of oxygenated blood through the arteries to the capillaries, where it nourishes the tissues, and the return of oxygen-depleted blood through the veins to the heart, where the cycle is renewed

circulatory system

the system concerned with the transport of blood and lymph, consisting of the heart, blood vessels, lymph vessels, etc

class

any of the taxonomic groups into which a phylum is divided and which contains one or more orders.

clone

a group of organisms or cells of the same genetic constitution that are descended from a common ancestor by asexual reproduction, as by cuttings, grafting, etc, in plants

codominant

(of genes) having both alleles expressed equally in the phenotype of the organism

cold-blooded

(of all animals except birds and mammals) having a body temperature that varies with that of the surroundings

conception

the fertilization of an ovum by a sperm in the Fallopian tube followed by implantation in the womb

copulate

to perform sexual intercourse

cytoplasm

the protoplasm of a cell contained within the cell membrane but excluding the nucleus: contains organelles, vesicles, and other inclusions

digestion

the act or process in living organisms of breaking down ingested food material into easily absorbed and assimilated substances by the action of enzymes and other agents

diploid

(of cells or organisms) having pairs of homologous chromosomes so that twice the haploid number is present

division

(in traditional classification systems) a major category of the plant kingdom that contains one or more related classes

DNA or deoxyribonucleic acid

deoxyribonucleic acid; a nucleic acid that is the main constituent of the chromosomes of all organisms (except some viruses). The DNA molecule consists of two polynucleotide chains in the form of a double helix, containing phosphate and the sugar deoxyribose and linked by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine. DNA is self-replicating, plays a central role in protein synthesis, and is responsible for the transmission of hereditary characteristics from parents to offspring

dominant

(of an allele) producing the same phenotype in the organism irrespective of whether the allele of the same gene is identical or dissimilar

dorsal

relating to the back or spinal part of the body

ecosystem

a system involving the interactions between a community of living organisms in a particular area and its nonliving environment

egg

the oval or round reproductive body laid by the females of birds, reptiles, fishes, insects, and some other animals, consisting of a developing embryo, its food store, and sometimes jelly or albumen, all surrounded by an outer shell or membrane

embryo

an animal in the early stages of development following cleavage of the zygote and ending at birth or hatching

environment

the external surroundings in which a plant or animal lives, which tend to influence its development and behaviour

enzyme

any of a group of complex proteins or conjugated proteins that are produced by living cells and act as catalysts in specific biochemical reactions

epidermis

the thin protective outer layer of the skin, composed of stratified epithelial tissue

evolution

a gradual change in the characteristics of a population of animals or plants over successive generations: accounts for the origin of existing species from ancestors unlike them

excretion

the act or process of excreting

family

any of the taxonomic groups into which an order is divided and which contains one or more genera

fermentation

a chemical reaction in which a ferment causes an organic molecule to split into simpler substances, esp the anaerobic conversion of sugar to ethyl alcohol by yeast

fertilization

the union of male and female gametes, during sexual reproduction, to form a zygote

flower

the reproductive structure of angiosperm plants, consisting normally of stamens and carpels surrounded by petals and sepals all borne on the receptacle (one or more of these structures may be absent). In some plants it is conspicuous and brightly coloured and attracts insects or other animals for pollination

foetus

the embryo of a mammal in the later stages of development, when it shows all the main recognizable features of the mature animal, esp a human embryo from the end of the second month of pregnancy until birth

food chain

a sequence of organisms in an ecosystem in which each species is the food of the next member of the chain

fossil

a relic, remnant, or representation of an organism that existed in a past geological age, or of the activity of such an organism, occurring in the form of mineralized bones, shells, etc, as casts, impressions, and moulds, and as frozen perfectly preserved organisms

fruit

the ripened ovary of a flowering plant, containing one or more seeds. It may be dry, as in the poppy, or fleshy, as in the peach; any fleshy part of a plant, other than the above structure, that supports the seeds and is edible, such as the strawberry; the specialized spore-producing structure of plants that do not bear seeds

fungus

any member of a kingdom of organisms (Fungi) that lack chlorophyll, leaves, true stems, and roots, reproduce by spores, and live as saprotrophs or parasites. The group includes moulds, mildews, rusts, yeasts, and mushrooms

gamete

a haploid germ cell, such as a spermatozoon or ovum, that fuses with another germ cell during fertilization

gene

a unit of heredity composed of DNA occupying a fixed position on a chromosome (some viral genes are composed of RNA). A gene may determine a characteristic of an individual by specifying a polypeptide chain that forms a protein or part of a protein (structural gene); or encode an RNA molecule; or regulate the operation of other genes or repress such operation

genus

any of the taxonomic groups into which a family is divided and which contains one or more species. For example, Vulpes (foxes) is a genus of the dog family (Canidae)

germination

to cause (seeds or spores) to sprout or (of seeds or spores) to sprout or form new tissue following increased metabolism

gestation

the development of the embryo of a viviparous mammal, between conception and birth: about 266 days in humans, 624 days in elephants, and 63 days in cats

gland

a cell or organ in man and other animals that synthesizes chemical substances and secretes them for the body to use or eliminate, either through a duct (exocrine gland) or directly into the bloodstream (endocrine gland)

gonad

an animal organ in which gametes are produced, such as a testis or an ovary

growth

the process or act of growing, esp in organisms following assimilation of food

haploid

a haploid cell or organism

heredity

the transmission from one generation to another of genetic factors that determine individual characteristics: responsible for the resemblances between parents and offspring

hermaphrodite

an individual animal or flower that has both male and female reproductive organs

hormone

a chemical substance produced in an endocrine gland and transported in the blood to a certain tissue, on which it exerts a specific effect

hybrid

an animal or plant resulting from a cross between genetically unlike individuals. Hybrids between different species are usually sterile

inheritance

the derivation of characteristics of one generation from an earlier one by heredity

invertebrate

any animal lacking a backbone, including all species not classified as vertebrates

kingdom

any of the major categories into which living organisms of the domain Eukarya are classified. Modern systems recognize four kingdoms: Protoctista (algae, protozoans, etc), Fungi, Plantae, and Animalia

Krebs cycle

a stage of tissue respiration: a series of biochemical reactions occurring in mitochondria in the presence of oxygen by which acetate, derived from the breakdown of foodstuffs, is converted to carbon dioxide and water, with the release of energy

life cycle

the series of changes occurring in an animal or plant between one development stage and the identical stage in the next generation

meiosis

a type of cell division in which a nucleus divides into four daughter nuclei, each containing half the chromosome number of the parent nucleus: occurs in all sexually reproducing organisms in which haploid gametes or spores are produced

menstruation

the approximately monthly discharge of blood and cellular debris from the uterus by nonpregnant women from puberty to the menopause

metabolism

the sum total of the chemical processes that occur in living organisms, resulting in growth, production of energy, elimination of waste material, etc

metamorphosis

the rapid transformation of a larva into an adult that occurs in certain animals, for example the stage between tadpole and frog or between chrysalis and butterfly

mitosis

a method of cell division, in which the nucleus divides into daughter nuclei, each containing the same number of chromosomes as the parent nucleus

muscle

a tissue composed of bundles of elongated cells capable of contraction and relaxation to produce movement in an organ or part

mutation

a change in the chromosomes or genes of a cell. When this change occurs in the gametes the structure and development of the resultant offspring may be affected

natural selection

a process resulting in the survival of those individuals from a population of animals or plants that are best adapted to the prevailing environmental conditions. The survivors tend to produce more offspring than those less well adapted, so that the characteristics of the population change over time, thus accounting for the process of evolution

nitrogen cycle

the natural circulation of nitrogen by living organisms. Nitrates in the soil, derived from dead organic matter by bacterial action, are absorbed and synthesized into complex organic compounds by plants and reduced to nitrates again when the plants and the animals feeding on them die and decay

nucleus

(in the cells of eukaryotes) a large compartment, bounded by a double membrane, that contains the chromosomes and associated molecules and controls the characteristics and growth of the cell

order

any of the taxonomic groups into which a class is divided and which contains one or more families.

organ

a fully differentiated structural and functional unit, such as a kidney or a root, in an animal or plant

osmosis

diffusion through any membrane or porous barrier, as in dialysis

ovulation

the process by which a mature ovum escapes from an ovary

ovum

an unfertilized female gamete; egg cell

parasite

an animal or plant that lives in or on another (the host) from which it obtains nourishment. The host does not benefit from the association and is often harmed by it

pathogen

any agent that can cause disease

pectoral

of or relating to the chest, breast, or thorax

photosynthesis

(in plants) the synthesis of organic compounds from carbon dioxide and water (with the release of oxygen) using light energy absorbed by chlorophyll

phylum

a major taxonomic division of living organisms that contain one or more classes. An example is the phylum Arthropoda (insects, crustaceans, arachnids, etc, and myriapods)

poikilothermic

(of all animals except birds and mammals) having a body temperature that varies with the temperature of the surroundings

pollen

a fine powdery substance produced by the anthers of seed-bearing plants, consisting of numerous fine grains containing the male gametes

pollinate

to transfer pollen from the anthers to the stigma of (a flower)

pollution

harmful or poisonous substances introduced into an environment

posterior

(of animals) of or near the hind end; (of a flower) situated nearest to the main stem

predator

any carnivorous animal

pregnancy

the period from conception to childbirth

progeny

the immediate descendant or descendants of a person, animal, etc

propagation

reproduction or multiplication, as of a plant or animal

protein

any of a large group of nitrogenous compounds of high molecular weight that are essential constituents of all living organisms. They consist of one or more chains of amino acids linked by peptide bonds and are folded into a specific three-dimensional shape maintained by further chemical bonding

protoplasm

the living contents of a cell, differentiated into cytoplasm and nucleoplasm

puberty

the period at the beginning of adolescence when the sex glands become functional and the secondary sexual characteristics emerge

recessive

(of a gene) capable of producing its characteristic phenotype in the organism only when its allele is identical

reproduction

any of various processes, either sexual or asexual, by which an animal or plant produces one or more individuals similar to itself

respiration

the chemical breakdown of complex organic substances, such as carbohydrates and fats, that takes place in the cells and tissues of animals and plants, during which energy is released and carbon dioxide produced (internal respiration)

RNA or ribose nucleic acid

ribonucleic acid; any of a group of nucleic acids, present in all living cells, that play an essential role in the synthesis of proteins. On hydrolysis they yield the pentose sugar ribose, the purine bases adenine and guanine, the pyrimidine bases cytosine and uracil, and phosphoric acid

ribosome

any of numerous minute particles in the cytoplasm of cells, either free or attached to the endoplasmic reticulum, that contain RNA and protein and are the site of protein synthesis

root

the organ of a higher plant that anchors the rest of the plant in the ground, absorbs water and mineral salts from the soil, and does not bear leaves or buds

seed

a mature fertilized plant ovule, consisting of an embryo and its food store surrounded by a protective seed coat (testa)

sexual reproduction

reproduction involving the fusion of a male and female haploid gamete

skeleton

a hard framework consisting of inorganic material that supports and protects the soft parts of an animal's body and provides attachment for muscles: may be internal (an endoskeleton), as in vertebrates, or external( an exoskeleton), as in arthropods

skin

the tissue forming the outer covering of the vertebrate body: it consists of two layers (the dermis and epidermis), the outermost of which may be covered with hair, scales, feathers, etc. It is mainly protective and sensory in function

soil

the top layer of the land surface of the earth that is composed of disintegrated rock particles, humus, water, and air

species

any of the taxonomic groups into which a genus is divided, the members of which are capable of interbreeding: often containing subspecies, varieties, or races. A species is designated in italics by the genus name followed by the specific name, for example Felis domesticus (the domestic cat)

spermatozoon or sperm

any of the male reproductive cells released in the semen during ejaculation, consisting of a flattened egg-shaped head, a long neck, and a whiplike tail by which it moves to fertilize the female ovum

spore

a reproductive body, produced by bacteria, fungi, various plants, and some protozoans, that develops into a new individual. A sexual spore is formed after the fusion of gametes and an asexual spore is the result of asexual reproduction

symbiosis

a close and usually obligatory association of two organisms of different species that live together, often to their mutual benefit

translocation

the transfer of one part of a chromosome to another part of the same or a different chromosome, resulting in rearrangement of the genes

transpiration

the act or process of transpiring; specif., the giving off of moisture, etc. through the pores of the skin or through the surface of leaves and other parts of plants

ventral

relating to the front part of the body; towards the belly

vertebrate

any chordate animal of the subphylum Vertebrata, characterized by a bony or cartilaginous skeleton and a well-developed brain: the group contains fishes, amphibians, reptiles, birds, and mammals

virus

any of a group of submicroscopic entities consisting of a single nucleic acid chain surrounded by a protein coat and capable of replication only within the cells of living organisms: many are pathogenic

vitamin

any of a group of substances that are essential, in small quantities, for the normal functioning of metabolism in the body. They cannot usually be synthesized in the body but they occur naturally in certain foods: insufficient supply of any particular vitamin results in a deficiency disease

viviparous

(of animals) producing offspring that as embryos develop within and derive nourishment from the body of the female parent

warm-blooded

(of birds and mammals) having a constant body temperature, usually higher than the temperature of the surroundings

X-chromosome

the sex chromosome that occurs in pairs in the diploid cells of the females of many animals, including humans, and as one of a pair with the Y-chromosome in those of males

Y-chromosome

the sex chromosome that occurs as one of a pair with the X-chromosome in the diploid cells of the males of many animals, including humans

zygote

the cell resulting from the union of an ovum and a spermatozoon

Dr Abiodun ✍️