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Flashcards in Chapter D Deck (33):
1

critical to ATP supply in first few minutes of exercise

Glycolysis

2

Rate of glycolysis and amount ATP production possible determined by

1. Training status
2. Muscle mass
3. Substrate availability

3

Glycolysis meets ----- of energy demands in an event lasting 2 min

60%

4

Glycolysis meets ----- of energy demands in an event lasting 4 min

30%

5

Glycolysis meets ----- of energy demands in an event lasting over 30 min

<5%

6

How does NADH provide energy?

Electrons shuttled through oxidative phosphorylation to generate energy

7

How does pyruvate provide energy?

Shuttled to mitochondria for complete oxidation or

Converted to lactate

8

What is the only source of energy for RBC?

Glycolysis

Why?
Bc they have no mitochondria

9

Major source of ATP for muscles under sever exercise conditions

Glycolysis

10

Immediate intake post exercise promotes

Glucose transport and glycogen synthesis for use in next training session

11

Glucose from diet is phosphorylated to

Glucose 6 phosphate in cell

12

Glucose from glycolysis is phosphorylated to

Glucose 1 phosphate

13

What does Phosphorylation do?

Traps glucose in cell

14

3 roles of glycolysis

Generate ATP directly
Generate NADH
Generate pyruvate

15

When does glycolysis predominate as energy-yielding pathway?

1.During rapid change from rest to activity; or rapid change from low to high intensity

2. During exercise when oxygen is limited (especially isometric)

3. When VO2 is 60% or more of VO2
max

16

Glycolytic pathway regulation deepens on concentration of

1. Glucose
2. Glycogen
3. Glucose 6 phosphate
4. ADP

17

Need for glycolysis determined by

Rate of ATP hydrolysis

18

ADP phosphorylation achieved by 2 glycolytic enzyme

1. Phosphoglycerate kinase

2. Pyruvate kinase

19

Primary targets for regulation of glycolytic pathway ?

3 irreversible reactions of glycolysis

1. Hexokinase
2.phosphofructokinase
3. Pyruvate kinase

20

Regulation of hexokinase

Regulated by produce of its reaction
If G6P increases too much, binds to hexokinase and slows reaction

Added effect of slowing glucose uptake into cell (limit substrate)

21

Major regulatory enzyme

Phosphofructokinase

22

List regulators of PFK1 activity

ATP
Citrate
ADP/AMP
Pi
F2,6 bisphosphate

23

How does ATP regulate PFK1

Allosteric inhibitor
Allosteric inhibition enhanced by H
Bind to negative allosteric site

24

How does citrate regulate of PFK1 activity

Provides index of fuel and ATP sufficiency

FA metabolism for ATP production increases citrate production

25

How do ADP/AMP regulate PFK1 activity?

Small changes in ATP lead to big changes in ADP and AMP concentration

26

How does Pi regulate PFK1 activity

During PCr regeneration of ATP, decrease in PCr inversely related to Pi concentration

Helps relieve H inhibition of PFK

27

Lactate might actually protect from fatigue due to

Loss of intracellular potassium

28

Potential sources of fatigue in working muscle

Depletion of phosphogens/increase in Pi

Change in intramuscular pH

29

PH changes during exercise

What is pH at rest?

7.4

30

PH changes during exercise

What is pH after high intensity exercise

7

31

PH changes during exercise

What is pH at point of fatigue

6.3

32

High [H+] affects fatigue in 2 ways:

1. inhibit glycolysis (does it?)

2. directly interfere with contractile mechanism (at physiologic temperature, does it?)

3. stimulate free nerve endings in muscle → pain)

33

What to do for recovery after exercise

Restore muscle Pcr and ATP
Remove accumulated lactate
Restore normal pH
Replace glycogen stores