Definitions Flashcards
Define Active Transport.
Active transport is the process In which energy is used to move the substance across a membrane against its concentration gradient.
I.e from higher to lower cont
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Define Osmosis.
Osmosis is the net movement of water molecules from a solution of higher to lower water potential through a p.p membrane.
Define differentiation.
Differentiation is the process by which a cell becomes specialised for a specific function.
Define ‘Tissue’
A tissue is a group of cells with similar structures which work together to perform a specific function.
Define Diffusion.
Diffusion is the net movement of particles from a region of higher concentration to lower concentration down a concentration gradient.
Define Carbohydrates.
Carbs are organic moleqs made up of C/H/O. The H and O atoms are present in 2:1
Define Condensation
A condensation rxn is a chemical rxn in which 2 simple moleqs join tgt to form a larger moleq with removal of 1 moleq of H²O
Define hydrolysis
Hydrolysis is a rxn in which a H²O moleq is needed to break up a larger moleq into smaller moleq
Define fats.
Fats are organic moleqs made up of C/H/O; but contain less O:H as compared to carbs
Define Protein
Proteins are organic moleqs made up of elements C/H/O/N. S may be present.
Define Enzyme
Enzymes are proteins that function as biological catalysts. They can alter or speed up chemical reactions. They are unchanged at the end of the reaction.
Define Digestion
Digestion is the process by which large food molecules are broken down into smaller, soluble molecules that can be absorbed into the body cells.
Define absorption
Absorption is the process whereby digested food substances are absorbed into the body cells.
Define Assimilation
Assimilation is the process whereby some of the absorbed food substances are converted into new protoplasm or used to provide energy.
Define Deamination.
Delamination is the process by which amino groups are removed from amino acids and converted into urea.
Define respiration
Respiration is the oxidation of food moleqs with the release of energy in living cells.
Define aerobic respiration.
Aerobic respiration us the oxidation of food moleqs in presence of oxygen with the release of a large amount of energy. CO² and H²O are released as waste products.
Define Anaerobic Respiration
Oxidation of food moleqs in the absence of oxygen. Releases less energy then aerobic respiration.
Define excretion
Excretion is the process by which metabolic waste products and toxic substances are removed from the body of an organism.
Define homeostasis
Homeostasis is the maintenance of a constant internal environment within narrow limits
Define negative feedback
Negative feedback is a sequence of events to bring about an opposite effect to changes detected to return in to normal.
Define reflex action
Reflex actions are an immediate response into a specific stimulus without conscious control.
Focusing
Focusing/Accommodation is the adjustment of the lens of the eye so that clear images of objects at different distances are formed on the retina.
Hormones
A hormone is a chemical substance produced in minute qtys by an endocrine gland. Transporter in the bloodstream to target organs where they exert its effects. After hormones have performed their functions they are destroyed by the liver.
Endocrine Glands
Endocrine glands are ductless glands that secrete hormones directly into the bloodstream to act on target organs.
Define Gene.
A DNA moleq may carry gene along its length. A gene is a sequence of DNA nucleotides that control the formation of a single polypeptide. And is a unit of inheritance borne on a particular locus of a chromosome.
Define genetic engineering.
Genetic engineering is a technique used to the transfer genes from 1 organism to another. Individual genes may be cut off from the veils of one organism and inserted into the cells of another organism of the same/diff species. The transferred gene should express itself in the recipient organism.
Define mitosis
Mitosis is a form of nuclear division that produces daughter nuclei containing the same number of chromosomes as the parent nucleus. The daughter nuclei are genetically equal.
Define Meiosis
Meiosis is a form of nuclear division that produces daughter nuclei containing half the number of chromosomes as the parent nucleus.
Monohybrid Inheritance
Inheritance involving only one pair of contrasting traits.
Codominance
Co-dominance results when the 2 alleles containing a trait both express themselves in the heterozygous condition.
Mutation
Mutation is a sudden random change in the structure of a gene or the number of chromosomes.
Define PS
PS is the process in which light energy absorbed by chlorophyll is transformed into chemical energy. The chemical energy is used to synthesise carbohydrates from H²O and CO². H²O and CO² are the raw materials for photosynthesis. Oxygen is released during the process.
Define Translocation.
The transport of manufactured food substances such as sugars and amino acids in plants is known as translocation.
Define Transpiration.
Transpiration is the loss of water vapour from a plant, mainly through the stomata of the leaves.
