Metabolic pathways

Question 1

What are metabolic pathways controlled by?

Answer 1

enzyme catalysed reactions within a cell

Question 2

How can rates of enzyme reactions be controlled?

Answer 2

By intracellular and extracellular signal molecules

Question 3

What do anabolic pathways require?

Answer 3

Energy and involve the biosynthetic processes

Question 4

What do catabolic pathways require?

Answer 4

They release energy and involve the breakdown of molecules

Question 5

What can most metabolic reactions do?

Answer 5

Be reversed

Question 6

what does the presence or removal of substrate do?

Answer 6

Drive a sequence of reactions in a particular direction

Question 7

What steps and routes do metabolic pathways have?

Answer 7

Reversible,irreversible steps and alternative routes

Question 8

What does the activity of an enzyme depend on?

Answer 8

Their flexible and dynamic shape

Question 9

Why do substarte molecules have a high affiny

Answer 9

for the active site

Question 10

When does induced fit occur?

Answer 10

The active site changes shape to better fit the substrate after the substrate binds

Question 11

What can the active site do to the substrate so they fit more closely

Answer 11

The active site can orientate

Question 12

What is the role of the active site of an enzyme

Answer 12

is affecting activation energy

Question 13

what lowers activation energy?

Answer 13

Enzymes

Question 14

What do products of enzyme reactions do?

Answer 14

They have a low affinity for the active site of the enzyme and are released form the active site

Question 15

what affects the direction and rate of an enzyme reaction?

Answer 15

The concentration of substrate and end product

Question 16

What do enzymes often do?

Answer 16

The act in groups or as multi-enzyme complexes

Question 17

What is non competitive inhibition?

Answer 17

Enzyme inhibition by a substance that permanently alters the active site of the enzyme
It cannot be reversed by increasing substrate concentration

Question 18

What is competitive inhibition?

Answer 18

slowing of reaction rate due to the presence of a substance resembling the substrate
Can be reversed by increasing substrate concentration

Question 19

How can competitive inhibition be reversed

Answer 19

Increasing substrate concentration

Question 20

When does feedback inhibition occur?

Answer 20

When the end product reaches a critical concentration

The end product then inhibits an earlier enzyme,blocking the pathway, prevents further synthesis of the end product

Question 21

Things that will affect the rate of reaction

Answer 21

Optimum pH
Temperature
Substrate concentration
Enzyme concentration

Question 22

What are the two reactions of metabolic pathways

Answer 22

Anabolic- synthesis (requires energy)

Catabolic-degradation (gives out energy)

Question 23

How are metabolic pathways controlled?

Answer 23

The presence or absence of particular enzymes and the regulation of the rate of reaction of key enzymes

Question 24

Describe the roles o genes in the control of metabolic pathways

Answer 24

Each step in a metabolic pathway is controlled by a specific enzyme, each enzyme is coded for by a gene

Question 25

Describe the effect of an increase in substrate concentration on the direction and rate of an enzyme reaction

Answer 25

Increase in substrate concentration drives the chemical reaction in the direction of the end product increases the rate of reaction