Unit 1: Enzyme Action and Inhibition Flashcards
what is a catabolic reaction?
a reaction that releases energy through the breakdown of a large molecule into smaller units
what is an anabolic reaction?
reaction that uses up energy to build up small molecules into large ones
what is metabolism?
the sum of all the anabolic and catabolic reactions
what is adenosine triphosphate made up of?
nitrogenous base - adenine
ribose sugar
three phosphate groups
what is the function of ATP?
to supply energy by hydrolysing ADP and pi
what is the activation energy?
energy needed to cause the molecules to react
what is glucose broken down to in animal cells during aerobic respiration?
CO2 and water and 38 ATP
what is glucose broken down to in animal cells during anaerobic respiration?
lactic acid ad 2 ATP
where does glycolysis take place?
in the cytoplasm
what is the net production of ATP molecules during glycolysis?
2
what process takes place in the matrix of the mitochondria?
kreb’s cycle
what is pyruvic acid converted to when it enters the mitochondria?
acetyl coenzyme A
what make up citric acid?
4 carbon compound and acetyl coenzyme A
name the enzyme involved in releasing carbon to produce carbon dioxide
decarboxylase
name the enzyme involved in releasing hydrogen?
dehydrogenase
where does the hydrogen transfer system occur?
cristae of the mitochondria
what is the end product of aerobic respiration
water
what its the final hydrogen acceptor?
oxygen
what instrument is used to measure respiration rate?
respirometer
How does an enzyme lower activation energy?
enzyme binds to the substrate and stresses some of its chemical bonds or binds to two substrates and forces them close together. theses effects lower activation energy (EA)
what happens to the speed and energy required for a chemical reaction without a catalyst?
the energy required is larger and the speed of the reaction is extremely slow
what is the function of protease?
hydrolysis of peptide bonds to break down proteins e.g. pepsin
what is the function of nuclease?
hydrolysis of phosphodiester bonds to break down nucleic acids e.g. EcoR1
what is the function of ATPase?
hydrolysis of phosphoester bond in ATP to form ADP and pi e.g.. sodium-potassium pump
what is the function of Kinase?
condensation reaction to add a phosphate group to another molecule e.g. kinase
what is the function of Phosphorylase?
catalyses the removal of a phosphate from a molecule by hydrolysis
what is the active site of an enzyme?
where the substrate binds
what is meant by induced fit?
The active site has a shape that complimentts the shape of the substrate but also the amino acids on the active site have an affinity for areas on the substrate molecule. ionic bonds and hydrogen bonds are formed between the active site and the substrate. The bonding brings about a conformational change in the enzyme, pulling the enzyme towards substrate. puts stress on bonds, activation energy lowered
what is hexokinase?
enzyme involved in the first stage in glycolysis
name factors affecting enzymes
temperature and pH
what is a competitive inhibitor?
reduces reaction rates by being similar to the substrate size, shape and charge pattern.
what happens to Vmax when the substrate concentration is increased - with a competitive inhibitor
will eventually dilute the competitive inhibitor so much that all enzyme molecules bind to the genuine substrate and vmax is reached, but at a higher substrate concentration
what is nitrogenase’s competitive inhibitor, similar to nitrogen
oxygen
what is a non-competitive inhibitor?
reduces reaction rates by binding to another part of the enzyme, away from the active site. the active site no longer fits the substrate
what happens to Vmax when the substrate concentration is increased - with a non-competitive inhibitor
a proportion of the enzyme molecules will be inactive and therefore Vmax is reduced
