- Abdomen: It describes the part of the body between the thorax and the pelvis.
- Absorb: It means to transform the digested food into living tissue.
- Acropetal: It refers to the way of development which in this case is upward from base to the apex.
- Aerobe: An Organism that requires air to live such as bacteria is called so.
- Aestivation: It is the period of hiding of animals or dormancy during the season of summer.
- Albumin: These are water soluble proteins found in white part of the egg, serum, milk etc.
- Aleurone: It refers to the protein that forms the outermost layer of endosperm in cereal grains.
- Algae: They are the most primitive aquatic plants having a thalloid structure, lacking true stem, root and leaves but are phototropic.
- Alkaloid: Organic bases which contain nitrogen such as nicotine, morphine derived from plants.
- Amphibian: Cold blooded, smooth skinned, when young are aquatic having gills which develop into adult having lungs.
- Amoeba: It refers to a protozoan occurring as water, soil and internal parasite having the characteristic feature of an indefinite form and shows movement by means of pseudopodia.
- Amoeboid: It resembles amoeba in form and means of movement.
- Amylase: An enzyme that converts starch or glycogen to sugar.
- Anabolism: It is the meta olic process involving the synthesis of complex materials from simpler ones.
- Anaerobic: Respiration in the absence of air is called so.
- Analogous Organs: Organs which are different in basic structure and origin but have similar functions.
- Anatomy: It refers to the structure of the body or part of an animal or plant.
- Androecium: The stamens of a flower are collectively called.
- Angiosperm: It refers to all flowering plants in which the seed is enclosed in an ovary.
- Animal: It is an organization of kingdom Animalia. The members have the characteristics of fixed structure, limited growth, locomotion, nonphotosynthetic, specialized sense organs and rapid response to stimuli.
- Annelid: Worms having cylindrical, segmented body with true coelom.
- Annual: Living and growing for only 1 year.
- Antenna: They are paired jointed sensory appendages present on the head of an insect.
- Anther: It forms the male, reproductive part of the flower that is present on the upper end of the stamen and produces and releases pollen.
- Anthocyanin: It is a water soluble pigment present in certain plants that impart red, blue and purple colour to flowers, fruits and leaves.
- Apocarpous: Flowers which have distinctly separated carpels.
- Arthropod: These are invertebrates characterized by jointed appendages and divisible into head, thorax and abdomen.
- Ascorbic Acid: It is also known as Vitamin C. It is a white crystalline vitamin found in citrus fruits used to cure scurvy.
- Asexual: It refers to reproduction involving only a single individual where there is no role of gametes as in binary fission.
- Aspergillus: It is a type of fungus.
- Atavism: It is the re-appearance or refunctioning of lost or vestigial organs.
- Autotrophic: Plants which can manufacture their own food by utilizing inorganic materials.
- Aves: Warm blooded or homoeothermic with body adapted for flight.
- Axil: It is the angle between the upper surface of a leafstalk or branch and the stem.
- Azotobacter: It refers to a nitrogen fixing bacteria.
- Bacillus: It is a group of unicellular or multicellular microscopic, prokaryotic organisms lacking chlorophyll.
- Bark: It is the protective outer covering of woody stems, trunks made up of dead cells.
- Bast: It is better known as phloem forming the outer fibrous layer of plants used in the manufacture of textiles.
- Biennial: Plants that live and grow for 2 years.
- Bifid: Divided into two lobes.
- Biflagellate: Having to flagella.
- Bilateral Symmetry: The arrangement of organs or parts of an organism in such a way that I can be divided into two halves along one plane only so that they form mirror images of each other.
- Binary Fission: Fission of a cell nucleus usually in protozoan like Amoeba which result in almost two same sized daughter cells.
- Biochemical Recapitulation: It is the repeating of biochemical process of some ancestors during the development of an organism.
- Biogenetic Law: It was proposed by Ernst Haekel in 1868. It states that “ontogeny repeats phylogeny” which means that an individual during its own development passes through its ancestral history in an abbreviated form.
- Biogeography: It is the study of distribution of plants and animals on the earth.
- Bioplasm: Another name for living protoplasm.
- Biped: An animal with two feet.
- Bisexual: It is also called hermaphrodite having both the male and female sex organs.
- Blubber: It is thick layer of far between the skin a and the muscle especially of whales and other marine animals.
- Blue Green Algae: The simplest form of plants and the first photoautotroph, also capable of fixing nitrogen.
- Body Cavity: The internal cavity of all multicellular organisms except sponges.
- Body Wall: It refers to the part consisting of ectoderm, endoderm and mesoderm that encloses the body cavity.
- Bole: It is the trunk of a tree.
- Botany: It refers to the study of plants, their classification, form, structure, function and economic importance.
- Bract: A Small leaf like part of the plant, sometimes showy and brightly coloured usually located below a flower or inflorescence.
- Bred Mould: Fungus that forms dense, cottony mass on bread.
- Brittle Star: They are marine organism related to the starfish but having long, slender and whip like arms.
- Bryophytes: Group of plants having stem and leaves but lack true root.
- Bud: It is an outgrowth of stem protected by scales, having a short stem and immature leaves or floral parts.
- Buttress Root: A root growing from the trunk of a tree for its additional support.
- Cambium: A layer of cells in the stems and roots of vascular plants that gives rise to secondary growth and helps in increase in girth of the plant.
- Carotene: A water soluble plant pigment that can be converted into vitamin a in the liver.
- Cartilaginous Fish: Any fish that has its skeleton entirely made up of cartilage:
- Catabolism: It is the conversion of complex molecules into simple forms by the release of energy.
- Cell: The basic structural unit of organism consisting of a nucleus and organelles capable of independent existence.
- Centriole: Microtubular structures found outside the nucleus in a clear area of cytoplasm called centrosome of animal cells, responsible for cell division.
- Chalaza: It is the part of an ovula that is located opposite to the micropyle and serves as an attachment for the integuments and the nucellus.
- Chemosynthesis: It is a process used to produce energy through the oxidation of chemicals.
- Chemotropism: It is the fast growth of an organism specially plant in response to chemical stimuli.
- Chlorophyll: It is the green pigment present in plants that trap the solar energy for photosynthesis.
- Chloroplast: The plastid present in plant cell containing chlorophyll.
- Chlorolsis: Abnormal condition of plant marked by deficiency in chlorophyll due to insufficient light or genetic disorders.
- Chromatophore: It is generally present in animal cells and is a pigment containing or producing cell.
- Class: Taxonomic category formed by group of related orders.
- Clitellum: Swollen, glandular, saddle like region in the spidermis of certain annelids.
- Cloaca: It is the cavity into which the intestinal, genital and urinal tracts open in vertebrates and some primitive mammals.
- Cneidaria: Aquatic organisms with diploblastic body, gastrovascular cavity called coelenterons and nematocysts or stinging cells.
- Coccus: Spherical bacteria.
- Cocoon: A covering of silk spun by the larvae of insects in protection of their pupal stage.
- Coelom: It refers to the body cavity in all animals except coelenterates.
- Coenocyte: Organism having multinucleate protoplasm due to mitotic division of nucleus but without septa formation.
- Cold Blooded: These are better known as poikilotherms where the body temperature varies with the external environment.
- Collenchyma: Plant tissue consisting of elongated rectangular cells with cell wall thickening material as cellulose or pectin.
- Compensation Point: The low light intensity at which the rate of photosynthesis equals the rate of respiration.
- Connecting Links: Living organisms having the characteristics of two different taxonomic categories are called so.
- Cross Pollination: Fertilization in which there is transfer of pollen from the anther of one flower to the stigma of another flower.
- Cryptogams: All the non flowering group of plants are collectively grouped under this.
- Cuticle: The protective layer constituting of cutin which covers the epidermis of plants.
