chapter 6 - cell metabolism / enzymes

Question 1

function of an enzyme

Answer 1

• a protein that allows chemical reactions to take place at normal body temperature

Question 2

what is activation energy

Answer 2

• energy required to start a chemical reaction

- enzymes decrease activation energy

Question 3

what is cell metabolism

Answer 3

• all chemical reactions that take place in cells / body

Question 4

types of cell metabolism

Answer 4

• catabolic: breaks down larger molecules into smaller molecules
• anabolic: joins smaller substrate molecules together to form larger molecules

Question 5

what is a substrate

Answer 5

• reaction which binds to the enzyme (molecule on which an enzyme reacts on)

Question 6

what is an active site

Answer 6

• the part of the enzyme that combines with the substrate

Question 7

what is the lock and key hypothesis

Answer 7

• states that the active sit specifically matches the shape of the substrate molecule (perfect fit)

Question 8

what are the factors affecting enzyme activity / rate of chemical reactions

Answer 8

1. concentration of enzymes: regulation of enzymes results in control of reactions and their rate
2. concentration of substrate: affects rate of reaction
3. temperature: optimum temp. 30-40 (45 results in deactivation)
4. pH: each enzyme has an optimum pH where the reaction takes place
5. presence of co-factors: ions, non-proteins, change shape of active site, allows enzymes to function not just join
6. presence of co-enzymes: non-protein, organic
7. enzyme inhibitors: slow / stop enzyme activity, get in the way

Question 9

what is an enzyme

Answer 9

• biological molecule that catalyse (increase rate of) chemical reactions
• protein
• acts on a substrate
• never breaks down