Test 3 (Slides)

Question 1

What is the role of phosphorylase?

Answer 1

Catalyses the breakdown of glycogen (glycogenolysis).

Question 2

How is phosphorylase activated and Inhibited?

Answer 2

Activated by calcium and AMP

Inhibited by ATP

Question 3

Under what conditions will glycogen phosphorylase activity be highest in the liver and skeletal muscle?

Answer 3

During high intensity exercise.

Question 4

What is the reaction catalysed by adenylate kinase?

Answer 4

2 ADPs are combined to form an ATP and AMP molecule

Question 5

What Is Gluconeogenesis?

Answer 5

The production of glycerol into glucose, in the liver

Question 6

What is meant by the term allosteric activation?

Answer 6

Enzyme activators that bind to locations on an enzyme that are distinct from the main active binding site leading to an increase in the function of the main active site.

Question 7

Can Phosphofructokinase (PFK) be allosterically activated? If so, what are the activators?

Answer 7

Yes by AMP, ADP and Pi.

Question 8

What affect does allosteric activation have on PFK enzyme activity and glycolytic flux (speed)?

Answer 8

Increases PFK activity.

As PFK is the rate limiting enzyme for glycolysis an increase in the allosteric activation of PFK leads to increased glycolytic flux and faster ATP resynthesis.

Question 9

What is the role of lactate dehydrogenase?

Answer 9

Catalyses the reversible reaction that produces lactate from pyruvate.

Question 10

Under what conditions will lactate dehydrogenase (LDH) activity be increased?

Answer 10

Lactate dehydrogenase activity is highest in type II fibres of skeletal muscle and it’s activity will be highest when glycolytic flux is high. i.e. during high intensity/maximal exercise.

Question 11

What is meant by the term rate of appearance (Ra)?

Answer 11

The amount of a molecule appearing in solution over time.

Question 12

What is meant by the term rate of disappearance (Rd)?

Answer 12

The amount of lactate disappearing from the blood over time into tissues.

Question 13

During Intense Exercise What Skeletal Muscle Energy System Is Predominantly Used?

Answer 13

Phosphagen, followed by Glycolytic

Question 14

What Is the reaction catalysed by myosin ATPase?

Answer 14

Hydrolysis/ breakdown of ATP to ADP

Question 15

What is the reaction catalysed by adenylate kinase?

Answer 15

Catalyses the inter-conversion of adenine nucleotides (ATP, ADP, and AMP).

Question 16

What catalyses the hydrolysis of ATP?

Answer 16

ATPase

Question 17

What provides a rapid supply of inorganic phosphate (Pi) for ATP resynthesis.

Answer 17

The breakdown of PCr by creatine kinase

Question 18

Adenylate kinase catalyses what?

Answer 18

2 ADP used to form ATP and AMP.

Question 19

After ~10 s, what is the predominant means of ATP supply primarily through glycogen degradation?

Answer 19

Glycolysis

Question 20

Glycolytic breakdown of one glycogen molecule provides how many ATP and how many per molecule of glucose?

Answer 20

3 ATP (2 ATP per molecule of glucose).

Question 21

What contributes to ATP supply during 10 s sprints?

Answer 21

Aerobic metabolism (mitochondrial ATP resynthesis)

Question 22

What did Coyle et al (1983) Describe the Lactate threshold as?

Answer 22

When lactate increased I mM above base line

Question 23

The Phosphagen System

Answer 23

ATPase
ATP + H20 > ADP + Pi + H+

               Creatine Kinase PCr + ADP + H+ ><	Cr + ATP

Adenylate Kinase 	 ADP + ADP >< ATP + AMP

> < = arrows

Question 24

How can an increase in skeletal muscle capillary and mitochondrial content affect endurance training?

Answer 24

Increased transit time of blood to surface area for oxygen diffusion

Allow for greater capacity to resynthesize ATP

Question 25

Fast Twitch Muscle fibers are high and low in what enzymes?

Answer 25

High in glycogenolysis enzymes

Low in oxidative enzymes

Question 26

What Happens to muscle PH during a 2 minute recovery period?

Answer 26

Drops by around 0.10 ph

Question 27

Glycogen Content During rest, 10 and 20-second sprints?

Answer 27

Rest 400 mmol.kg-1

During 10s - Depletes 13%

During 20s -Depletes 18%

Question 28

Lactate content during rest, 10 and 20-second sprints?

Answer 28

Rest - 5 mmol.kg

10s - 50 mmol.kg

20s- 80 mmol.kg

Question 29

PCr content during during rest, 10 and 20-second sprints?

Answer 29

Rest 80 mmol.kg

10s - Depletes 55%

20s- Depletes 73%

Question 30

Creatine content during rest, 10 and 20-second sprints?

Answer 30

Rest - 38 mmol.kg

10s - 80 mmol.kg

20s - 90 mmol.kg

Question 31

ATP Metabolism During Rest, 10 & 20 second sprints?

Answer 31

During Rest - 25 mmol.kg

10s - 20 mmol.kg

20s - 18 mmol.kg

Question 32

Importance of creatine kinase in ATP turnover during, recovery from and maximal sprint exercise?

Answer 32

During a sprint mitochondrial membrane (miCK) breaks down PCr to generate ATP

PCr stores are therefore reduced

In recovery miCK resynthesises PCr from ATP and free Cr

Question 33

Explain the effect of greater density of mitochondria per unit per volume of skeletal muscle on the recovery of PCr between repeated sprints?

Answer 33

Synthesises ATp through oxidate phosphorylation

Allows for greater capacity for ATP synthesis

Question 34

Aerobic system contribution to 10s and 20s sprints?

Answer 34

Bogdanis reported an increase in VO2 between 10s and 20s sprints. (1.3 L/min to 2.4 L/min)

Estimated aerobic system contributed 14% and 27% towards energy during sprints

Question 35

What is OBLA and how any mmol? L of lactate is this?

Answer 35

Onset blood lactate accumulation

Blood Lactate value of 4mmol/L

Question 36

Explain how increases in skeletal muscle AMP concentrations affect glycolytic flux?

Answer 36

1. The rapid breakdown of ATP during very high-intensity exercise increases the AMP concentration
2. PFK is the rate-limiting enzyme in glycolysis
3. PFK is activated allosterically by AMP, thus increases in AMP lead to increases in the activity of PFK
4. Increases PFK activity thus means an increase in the glycolytic flux