Glossary of Biological Terms With Full Definitions (Alphabetical Order ) D-M

Deciduous: Trees that shed all their leaves at the end of the season.
Denitrifying Bacteria: Refers to soil bacteria that converts nitrate to ammonia.
Dhobi’s Itch: A fungal disease that is contracted from other’s dirty clothes.
Diffusion: Spontaneous movement of a solvent from a region of higher concentration to a region of lower concentration.
Dioecius: Plants in which the male and female flowers are borne on separate plants.
Diplococcus: These refer to paired spherical bacteria.
Diploid: Having 2n no of chromosomes for each characteristic except sex.
Echinoderm: These are marine invertebrates with calcareous skeleton beneath the skin usually covered with spines.
Egest: Discharge or excretion from the body.
Endoplasmic Reticulum: Membrane bound sacs in the cytoplasm of cell that functions in intracellular transport.
Endosmosis: The inward movement of water into the cell.
Enucleate: Cell lacking nucleus.
Epigeal Germination: In this type the cotyledons come above the soil.
Epiphyte: Plant that grows on another for only support but does not derive any nutrition.
Evergreen: Trees that do not shed all their leaves at the same time.
Evolution: It is defined as continuous genetic variation or adaptation through generations.
Exosmosis: The outward movement of water from the cell.
Family: Taxonomic category between order and genus.
Fatty Acids: These are monobasic acids obtained from plants and animals.
Fermentation: Chemical break down of complex material into simple forms.
Fiber: These are elongated, thick walled cells that give strength and support to the plant tissue.
Flower: It is the reproductive part of angiosperm plants having the male and female parts.
Food Chain: A number of interconnected organisms in an ecological community in which one member feeds on the lower member and is eaten in turn by a higher member.
Food Web: A Number of interconnected food chains in an ecological community from a food chain.
Fossils: These are the impressions of hard parts of organisms generally preserved in sedimentary rocks.
Fruit: It is the ripened ovary of a seed plant.
Fruiting Body: It is the spore producing part of fungus.
Fungus: Organism lacking chlorophyll and thus is saprophytic or parasitic.
Genus: Taxonomic category constituting group of closely related species.
Geotropism: It is the response of a plant to the gravity or movement its root shows towards the earth.
Gill: It is the other name for respiratory organs in fishes.
Gill Bar: Skeleton structures in the pharyngeal walls of the fishes that supports the tissue separating the gill slits.
Glycogen: Form in which carbohydrate is stored in animals.
Glycolysis: The biochemical bread down of glucose to lactic acid with the production of ATP.
Golgi Bodies: Membranous vesicle in the cell related to the formation of secretions in the cell.
Ground Tissue: Plant tissue such as pith or cortex that is not specialized for any particular function.
Growth: It is an increase in mass or volume of an organism accompanies by irreversible change in form an structure.
Guard Cell: Either of the epidermal cell that controls the opening and closing of stomata in plants.
Gum: It is a viscous substance exuded by plants.
Gymnosperm: Plants in which seeds are not enclosed within ovary.
Gynoecium: It is the female reproductive part of a flower.
Guttation: Loss of water from the special pores on leaves called hydathodes in the form of liquid instead of vapour.
Habitat: Type of environment in which an organism normally lives.
Haploid: The number of chromosomes in the germ cell is half the number of chromosome in the somatic cell.
Haustoria: Organ of obtaining food from hosts by the parasitic plants.
Herb: It is an angiosperm plant with soft, fleshy stem.
Heterotrophic: Nutrition derived from organic substances.
Hibernation: The event of animals remaining dormant in the water season.
Histology: It is the anatomical study of plant or animal tissue.
Holophytic: Organisms that manufacture of food by photosynthesis.
Holozoic: Organisms that obtain nourishment from complex organic material.
Homoeothermic: It is also called warm blooded which maintain relatively constant body temperature independent of the external environment.
Homologous Organs: Organs which are similar in basic structure and origin but adapted to perform different functions.
Hydrotropism: Movement of plant part in response to stimulus of water.
Hypertonic Solution: Solution whose concentration is greater than that of the cell sap.
Hypha: Thread like filaments forming the mycelium of fungus.
Hypogeal Germination: A type in which the cotyledons remain below the soil.
Hypotonic Solution: Solution whose concentration is less than that of the cell sap.
Inclusion: Any non living mass in the cytoplasm is called so.
Inflorescence: It refers to the arrangement of flowers on the stalk.
Ingest: The process of taking into the body.
Internode: Part of stem between two nodes is called so.
Involucre: Whorl or bract around a flower.
Imbibation: The process of uptake of liquid by hydrophilic substance.
Impermeable: Membrane that does not allow solute or solvent to pass through.
Isotonic Solution: Solution whose concentration is equal to that of the cell sap.
Karyokinesis: Nuclear division is better known as so.
Kingdom: The broadcast taxonomic category of organism.
Kreb’s Cycle: It is an anaerobic process taking place in the mitochondria where pyruvic acid is converted to carbon dioxide and water vapour.
Law of Limiting Factor: When a process is governed by more than one factor the rate of process is governed by the factor which is in the least amount.
Lamina: The expanded portion of a leaf.
Latex: Milky, viscous plant sap that exudates from the stem.
Leaf: Flattened, green structure of plant functioning as the photosynthesis and respiratory centre.
Legume: A pod that splits two halves with seeds attached to the lower end of the halves.
Lenticels: Pores larger than stomata on the stem surface of woody plants that allows transpiration and exchange of gases.
Leucoplast: A colourless plastid in the cytoplasm of plant cell around which starch collects.
Ligule: Sheath like organ at the base of the leaf.
Living Fossil: A living organism with ancient characters is called so.
Lysosome: Cell organ that contains hydrolases for breaking down the cell material.
Macronutrient: Elements required in large proportion by plants for growth.
Mammals: Warm blooded with four chambered heart.
Meiosis: It is also called reduction division that reduces the number of chromosome in the reproductive cells to half that in the somatic cells.
Mesoglea: It is a layer present in between the ectoderm and the endoderm in coelenterates.
Mesophyll: It is the soft tissue of leaf containing chloroplasts present between the upper and lower epidermis.
Metabolism: The combination of physical and chemical processes that helps in the maintenance of life.
Microsporophyll: It is the structure in ferns that bears microsporangia.
Missing Links: These extinct organism that had the characteristic of two different groups of organisms and confirm the path of evolution between them.
Mitochondria: It is also called power house of the cell it is double layered with inner layer in folds called cristae.
Mitosis: A type of cell division in which the nucleus divides to produce two daughter cells with type same number of chromosomes as that of the parent cell.
Mollusca: The organisms have soft, unsegmented body and ventral, muscular foot for locomotion.