Unit 2 Metabolism and Survival
Glossary
Activation energy the minimum energy required by reactants to allow reaction to occur
Active site the region of an enzyme molecule where the enzyme acts on the substrate
Aestivation dormancy in response to high temperature or drought
Anabolic a reaction which requires energy and builds up molecules
Archaea group of single-celled microorganisms
ATP synthase an enzyme which produces ATP
Biological catalysts catalysts made of protein that are only found in living cells
Calorimeter a piece of equipment used to measure heat generation from an organism to allow metabolic rate to be calculate
Catabolic a reaction which releases energy and breaks down molecules
Citric acid cycle the second stage of respiration, where acetyl CoA and oxaloacetate join to formcitrate and a series of reactions which return citrate to oxaloacetate
Competitive inhibition competitive inhibition of enzyme activity occurs when an inhibitor, resembling thestructure of the substrate, binds to the active site of the enzyme and blocks thebinding of the substrate
Daily torpor a period of reduced activity in organisms with high metabolic rates
Dehydrogenase an enzyme which removes hydrogen ions and electrons from substrates
Dormancy a condition of biological rest or inactivity characterised by cessation of growth or
development and the suspension of many metabolic processes
Effector cells, muscles or glands which perform responses to stimuli
Electron transport chainthe final stage of respiration where high energy electrons and hydrogen ions areused to synthesise ATP
Extremophile an organism which is able to live in extreme conditions e.g. high temperature
FAD a co-enzyme which easily attaches to hydrogen ions, but releases them when they
are required
Feedback inhibition regulation of enzyme activity where the first enzyme of a metabolic pathway isinhibited by the reversible binding of the final product of the pathway
Fermentation a type of respiration which takes place in the absence of oxygen
Glycolysis the first stage of respiration where glucose is broken down into pyruvate
Heterotrophic an organism which gains energy by consuming other organisms
Hibernation an inactive state resembling deep sleep in which certain animals living in cold
climates pass the winter
Hypothalamus part of the brain which monitors and regulates temperature
Induced fit model a model of an enzyme-substrate reaction that causes a conformational change inthe active site of the enzyme that allows the substrate to fit perfectly
Ligase an enzyme which joins fragments of DNA together
Metabolites the intermediates and products of metabolic reactions that take place in organisms
Migration a process which avoids metabolic adversity by expending energy to relocate to a
more suitable environment
Mitochondria a structure in the cell responsible for producing energy
NAD a co-enzyme which easily attaches to hydrogen ions, but releases them when they
are required
Negative feedback homeostasis; the process by which an increase in one factor causes a decreasein another factor, thereby maintaining equilibrium around a set point (norm)
Non-competitive inhibition a molecule binds to part of the enzyme away from the active site, and causesa conformational change in the active site of the enzyme, thereby inhibiting thebinding of the appropriate substrate molecule
Nutrient medium a mixture of nutrients (including carbon and nitrogen sources) required for growth
Plasmid a circular, self-replicating DNA molecule that carries only a few genes
Receptor cells which monitor changes in environment
Respirometer a piece of equipment used to measure the rate of respiration
Restriction endonuclease an enzyme that cuts specific target sequences of DNA
Selectively permeable a property of a membrane which means that substances do not freely pass throughit; the membrane allows the passage of certain small molecules, but excludesmany other molecules
Vasoconstriction contraction in diameter of a blood vessel, thus reducing blood flow
Vasodilation enlargement in diameter of a blood vessel, thus increasing blood flow
VO2max the maximum rate at which the body is able to take up and use oxygen
Wild-type describes the phenotype of the typical form of a species as it occurs in nature