VCE Biology Unit 3 Glossary Terms- Chapter 2

beamcj's version from 2016-05-27 01:54


Question Answer
activation energyEnergy required to begin a reaction.
active siteThe site on the surface of an enzyme that binds the substrate molecule.
affinityMeasure of the ease with which an enzyme binds with its substrate.
amylaseEnzyme that breaks down starch.
anabolismThe building of larger molecules from smaller molecules, a process requiring energy to build new bonds.
apoptosisProgrammed cell death: process of cell suicide that involves a characteristic series of events leading to death of the cell.
catabolismThe breakdown of macromolecules into smaller molecules, releasing energy.
catalystA substance that increases the rate of a reaction, without being consumed in the reaction; includes enzymes.
coenzymeVery small molecule that combines with an enzyme and is necessary for its activity.
cofactorMetallic cation required for the proper function of particular enzymes.
condensation reactionProcess in the synthesis of polymers where the linking of subunits is associated with the removal of a water molecule. (dehydration)
critical temperatureTemperature at which denaturation of enzyme molecules begins to occur as temperature rises.
dehydrationProcess in the synthesis of polymers where the linking of subunits is associated with the removal of a water molecule. (condensation reaction)
denaturationIrreversible change in protein structure, usually as a result of heating above a certain critical temperature.
DNA (deoxyribonucleic acid)A nucleic acid made up of a sequence of deoxyribose sugars and bases (adenine, cytosine, guanine and thymine) linked by phosphate bonds.
endergonicReaction that requires an input of energy in order to continue.
endoplasmic reticulumLayers of intracellular membranes; links between membrane-bound organelles and the plasma membrane; may be rough or smooth.
enzymeProtein that catalyses (increases the rate of) chemical reactions in living organisms. They are specific for a particular chemical reaction and may be used over and over again.
exergonicChemical reaction that results in a net release of energy.
exocytosisFusion of a vesicle with the cell membrane expelling its contents outside the cell.
galactosaemiaA rare genetic metabolic disorder that affects an individual's ability to metabolize the sugar galactose properly.
Golgi apparatusAn organelle composed of a stack of smooth membranous cisternae (flattened sac-like structures) in which proteins and polysaccharides are assembled and packaged in vesicles for export from the cell.
hydrolysisBreakdown of polymers into subunits involving the addition of a water molecule.
lactose intoleranceThe inability of adults and children to digest lactose, a sugar found in milk and to a lesser extent in other dairy products.
lipaseEnzyme that breaks down lipids.
lysosomeMembrane-bound vesicle, found in most animal cells, in which powerful enzymes break down debris and foreign molecules.
messenger RNARibonucleic acid molecule transcribed from DNA in the nucleus which passes into the cytoplasm and binds to a ribose molecule, where it is translated into an amino acid sequence (polypeptide).
metabolismThe total of the physical and chemical processes by which energy and matter are made available by an organism for its own use; controlled by enzymes.
nuclear membraneThe double lipid bilayer membrane which surrounds the genetic material and nucleolus in eukaryotic cells
nuclear poresProtein-lined channels in the nuclear envelope that regulates the transportation of molecules between the nucleus and the cytoplasm.
nucleolusDark-staining body in the nucleus; site of synthesis of ribosomal RNA.
nucleusIn a eukaryotic cell, a large organelle containing chromosomes (which control cellular activities) surrounded by a double-layer nuclear membrane with numerous nuclear pores.
optimum temperatureTemperature at which an enzyme's catalytic activity is greatest.
pHA measure of alkalinity or acidity, measured on a scale of 0 (most acid) to 14 (most alkaline).
phenylkeronuria (PKU)An inherited inability to metabolize phenylalanine which, if untreated, causes brain and nerve damage.
proteaseEnzymes that cut proteins into smaller polypeptides.
RNA (ribonucleic acid)Nucleic acid made up of a sequence of ribose sugars and bases (adenine, cytosine, guanine and uracil) linked by phosphate bonds.
ribosomeTiny organelle often attached to the endoplasmic reticulum; composed of protein and RNA; the site of protein synthesis.
substrateA substance that is acted on by a catalyst such as an enzyme.
tonoplastThe membrane surrounding the vacuole in plant cells; regulates uptake into the vacuole.
turgorA state of high internal fluid pressure that is the result of the osmotic intake of water into plant cells whose volume is limited by the presence of a rigid cell wall.
vacuoleMembrane-bound liquid-filled space between cells. They are usually large and are involved in storage and turgidity.

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