Metabolic Pathways

Question 1

What is a metabolic pathway?

Answer 1

• one chemical is changed to another, then to another via a series of enzyme controlled steps

Question 2

What’s is an anabolic pathway?

Answer 2

• the synthesis of smaller molecules into larger molecules and requires energy

Question 3

What is a catabolic pathway?

Answer 3

• the synthesis of larger molecules down to smaller molecules and release energy

Question 4

What is each step in a metabolic pathway driven by?

Answer 4

• a particular enzyme and gene codes for each enzyme

Question 5

What is enzyme action controlled by?

Answer 5

• the presence or absence of particular enzymes

Question 6

What is enzyme action regulated by?

Answer 6

• the rate of reaction of key enzymes

Question 7

How to enzymes speed up chemical reactions?

Answer 7

• lowering the activation energy

Question 8

What is activation energy?

Answer 8

• the energy required for the reactants you reach the translation state

Question 9

What happens when the active site and substrate molecules combine?

Answer 9

• the reactants are orientated to the active site
• the activation energy is lowered
• the products that have a lower affinity for the active site are released

Question 10

What’s is induced fit?

Answer 10

• when the substrate enters the active site it changes slightly making it fit the molecule substrate snugly

Question 11

What happens at low concentrations of substrate?

Answer 11

• reaction rate is low due to too few substrate molecules to make full use of all the active sites

Question 12

What does an increase in the substrate cause?

Answer 12

• an increase in reaction rate as more of the active sites are in use

Question 13

How do inhibitors control the metabolic pathways?

Answer 13

• by decreasing the rate of the enzyme action

Question 14

What do competitive inhibitors do?

Answer 14

• bind to the active site preventing the substrate from binding

Question 15

How can competitive inhibitors be overcome?

Answer 15

• increasing the substrate concentration as there is a higher chance of enzyme-substrate interaction

Question 16

What do non-competitive inhibitors do?

Answer 16

• become attached to a non-active site causing a change in shape of active site and cannot be reversed by increasing substrate concentration

Question 17

Why does feedback inhibition happen?

Answer 17

• concentration of end product builds up and reaches critical concentration

Question 18

What does feedback inhibition do?

Answer 18

• it inhibits an earlier enzyme, blocking the pathway and so prevents further synthesis of the end product