lecture 37 - exercise

Question 1

Why does exercising muscle have a high ATP requirement?

Answer 1

Needs a large and continuous supply for use in the contractile machinery of muscle

Question 2

What are the 2 types of exercise, though most involves a proportion of each?

Answer 2

Anaerobic and aerobic

Question 3

What is anaerobic exercise?

Answer 3

High intensity, rapid generation of energy, without oxygen using the muscles energy stores

Question 4

What is aerobic exercise?

Answer 4

Prolonged sustained exercise, with energy produced from fuels stored in a muscle and fuels circulating the blood

Question 5

What energy sources does muscle in anaerobic exercise use?

Answer 5

Local energy generation from phosphocreatine and glycogen which is stored in the muscle

Question 6

What energy sources does muscle in aerobic exercise use?

Answer 6

Fuels stored in muscle (phosphocreatine and glycogen) as well as fuels circulating in the blood, such as glucose and fatty acids that are mobilised from the liver’s glycogen stores and adipose tissue TAG stores.

Question 7

How does phosphocreatine rapidly regenerate ATP in muscle?

Answer 7

Contains a high entry phosphate that can be transferred to ADP by catalysis with creatine kinase.

Question 8

In what form do muscles store high energy phosphate?

Answer 8

In phosphocreatine, which can then be transferred rapidly to ADP, as ATP cannot be stored by the body .

Question 9

What enzyme is used to cleave the monomers of glycogen off into glucose-1-phosphate molecules?

Answer 9

Glycogen phosphorylase

Question 10

What is glycogenolysis coupled with to produce ATP rapidly in anaerobic conditions?

Answer 10

Glycolysis

Question 11

What enzyme regulates glycogen mobilisation?

Answer 11

Glycogen phosphorylase

Question 12

What is the glycogen phosphorylase enzyme stimulated by in active muscle.

Answer 12

Ca2+ and adrenaline

Question 13

What is the rate-limiting, regulatory step of glycolysis catalysed by?

Answer 13

PFK (phosphofructokinase)

Question 14

In resting muscle, what is PFK inhibited by, and why?

Answer 14

ATP, citrate and creatine phosphate - they indicate that sufficient ATP is available so PFK is not needed to catalyse glycolysis.

Question 15

What activates PFK, and why?

Answer 15

AMP and Pi, as they indicate that further ATP needs to be made to supply energy.

Question 16

What proportions of acetyl-CoA come from glucose and from fatty acids?

Answer 16

50% form glucose, 50% from fatty acids

Question 17

Are type 1/red muscle fibres adapted for anaerobic or aerobic metabolism?

Answer 17

Aerobic

Question 18

Are type 2/white muscle fibres adapted for anaerobic or aerobic metabolism?

Answer 18

Anaerobic

Question 19

What is the metabolic character of type 1/red muscle fibres?

Answer 19

Oxidative

Question 20

What is the metabolic character of type 2/white muscle fibres?

Answer 20

glycolytic

Question 21

Why do type 1/red muscle fibres produce energy more slowly that type 2/white muscle fibres?

Answer 21

Type 1 complete oxidise fuels via beta-oxidation, CAC etc. while Type 2 uses rapid anaerobic glycolysis using local energy stores

Question 22

What are the endogenous energy stores utilised by Type 2 muscle for rapid energy use?

Answer 22

Phosphocreatine and glycogen

Question 23

What type of enzyme increase in amount when there is endurance training of muscle?

Answer 23

Regulatory enzymes of the oxidative metabolic pathways, because type 1 muscle fibres are targeted and they facilitate the complete oxidation of fuels to produce energy.