Unit 1: Enzyme Action and Inhibition

Question 1

what is a catabolic reaction?

Answer 1

a reaction that releases energy through the breakdown of a large molecule into smaller units

Question 2

what is an anabolic reaction?

Answer 2

reaction that uses up energy to build up small molecules into large ones

Question 3

what is metabolism?

Answer 3

the sum of all the anabolic and catabolic reactions

Question 4

what is adenosine triphosphate made up of?

Answer 4

nitrogenous base - adenine
ribose sugar
three phosphate groups

Question 5

what is the function of ATP?

Answer 5

to supply energy by hydrolysing ADP and pi

Question 6

what is the activation energy?

Answer 6

energy needed to cause the molecules to react

Question 7

what is glucose broken down to in animal cells during aerobic respiration?

Answer 7

CO2 and water and 38 ATP

Question 8

what is glucose broken down to in animal cells during anaerobic respiration?

Answer 8

lactic acid ad 2 ATP

Question 9

where does glycolysis take place?

Answer 9

in the cytoplasm

Question 10

what is the net production of ATP molecules during glycolysis?

Answer 10

2

Question 11

what process takes place in the matrix of the mitochondria?

Answer 11

kreb’s cycle

Question 12

what is pyruvic acid converted to when it enters the mitochondria?

Answer 12

acetyl coenzyme A

Question 13

what make up citric acid?

Answer 13

4 carbon compound and acetyl coenzyme A

Question 14

name the enzyme involved in releasing carbon to produce carbon dioxide

Answer 14

decarboxylase

Question 15

name the enzyme involved in releasing hydrogen?

Answer 15

dehydrogenase

Question 16

where does the hydrogen transfer system occur?

Answer 16

cristae of the mitochondria

Question 17

what is the end product of aerobic respiration

Answer 17

water

Question 18

what its the final hydrogen acceptor?

Answer 18

oxygen

Question 19

what instrument is used to measure respiration rate?

Answer 19

respirometer

Question 20

How does an enzyme lower activation energy?

Answer 20

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)

Question 21

what happens to the speed and energy required for a chemical reaction without a catalyst?

Answer 21

the energy required is larger and the speed of the reaction is extremely slow

Question 22

what is the function of protease?

Answer 22

hydrolysis of peptide bonds to break down proteins e.g. pepsin

Question 23

what is the function of nuclease?

Answer 23

hydrolysis of phosphodiester bonds to break down nucleic acids e.g. EcoR1

Question 24

what is the function of ATPase?

Answer 24

hydrolysis of phosphoester bond in ATP to form ADP and pi e.g.. sodium-potassium pump

Question 25

what is the function of Kinase?

Answer 25

condensation reaction to add a phosphate group to another molecule e.g. kinase

Question 26

what is the function of Phosphorylase?

Answer 26

catalyses the removal of a phosphate from a molecule by hydrolysis

Question 27

what is the active site of an enzyme?

Answer 27

where the substrate binds

Question 28

what is meant by induced fit?

Answer 28

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

Question 29

what is hexokinase?

Answer 29

enzyme involved in the first stage in glycolysis

Question 30

name factors affecting enzymes

Answer 30

temperature and pH

Question 31

what is a competitive inhibitor?

Answer 31

reduces reaction rates by being similar to the substrate size, shape and charge pattern.

Question 32

what happens to Vmax when the substrate concentration is increased - with a competitive inhibitor

Answer 32

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

Question 33

what is nitrogenase’s competitive inhibitor, similar to nitrogen

Answer 33

oxygen

Question 34

what is a non-competitive inhibitor?

Answer 34

reduces reaction rates by binding to another part of the enzyme, away from the active site. the active site no longer fits the substrate

Question 35

what happens to Vmax when the substrate concentration is increased - with a non-competitive inhibitor

Answer 35

a proportion of the enzyme molecules will be inactive and therefore Vmax is reduced