Chp 3 Bioenergetics of Exercise and Training

Question 1

hydrolysis

Answer 1

the breakdown of one molecule of ATP to yield energy

Question 2

myosin APTase

Answer 2

enzyme that catalyzes ATP hydrolysis for crossbridge recycling

Question 3

calcium ATPase

Answer 3

hydrolyze ATP for pumping calcium into the sarcoplasmic reticulum

Question 4

sodium-potassium ATPase

Answer 4

for maintaining the sarcolemmal concentration gradient after depolarization

Question 5

amount of ATP stores

Answer 5

80-100g at any given time

Question 6

ATP concentration may decrease up to _____.

Answer 6

50 - 60%

Question 7

CP concentration is _____ times higher than ATP concentration.

Answer 7

4 - 6

Question 8

Which muscle fiber type has higher concentrations of CP?

Answer 8

Type II

Question 9

What is pyruvate?

Answer 9

an end result of glycolysis

Question 10

Glycolysis is the breakdown of _____ —- either _____ stored in the muscle or _____ in the blood.

Answer 10

carbohydrate; glycogen; glucose

Question 11

Pyruvate may proceed in one of two directions:

Answer 11

1. be converted to lactate in the sarcoplasm –> fast glycolysis
2. be shuttled into the mitochondria –> slow glycolysis

Question 12

Lactate is the product of _____.

It is often used

1. as _____, especially in Type I and cardiac muscle fibers.
2. in _____ – the formation of _____ from _____ – during extended exercise and recovery

Answer 12

lactate dehydrogenase reaction

energy substrate; gluconeogenesis; glucose; noncarbohydrate sources

Question 13

Cori cycle

Answer 13

lactate can be transported in the blood to the liver, where it is converted to glucose

Question 14

When pyruvate enters the mitochondria, it is converted to _____ which will then enter the Krebs cycle.

Answer 14

acetyl-CoA

Question 15

The _____ molecules enter the _____, where they can be used to resynthesize ATP.

Answer 15

NADH; electron transport system

Question 16

oxidative phosphorylation

Answer 16

the resynthesis of ATP in the electron transport chain (ETC)

Question 17

substrate-level phosphorylation

Answer 17

the direct resynthesis of ATP from ADP during a single reaction in the metabolic pathways

Question 18

signs of increased ATP hydrolysis:
high concentrations of _____, _____, and _____.
slight decrease in _____ and _____.

—> increased rate of glycolysis

Answer 18

ADP; Pi, ammonia

pH; AMP

Question 19

Markedly lower _____, _____, _____, _____, and _____ will inhibit glycolysis

Answer 19

pH; ATP; CP; citrate; free fatty acids

Question 20

Other factors that contribute to the regulation of glycolysis:

Answer 20

concentrations and turnover rate of glycolytic enzymes: hexokinase, PFK (phosphofructokinase), pyruvate kinase

Question 21

Lactate threshold (LT)

Answer 21

the exercise intensity or relative intensity at which blood lactate begins an abrupt increase above the baseline concentration

Question 22

The LT usually begins at _____ of maximal oxygen uptake in untrained individuals and at _____ in aerobically trained athletes.

Answer 22

50 - 60%; 70 - 80%

Question 23

What is onset blood lactate accumulation (OBLA)?

It occurs when the concentration of blood lactate reaches _____.

Answer 23

a second increase in the rate of lactate accumulation has been noted at higher relative intensities of exercise

4 mmol/L

Question 24

_____ stored in fat cells can be broken down by enzyme, _____, to produce _____ and _____.

Answer 24

Triglycerides; hormone-sensitive lipase; free fatty acids; glycerol

Question 25

Free fatty acids enters the _____, where they undergo _____, a series of reactions in which the free fatty acids are broken down, resulting in the formation of _____ and _____. The _____ enters Krebs cycle. The _____ are carried by _____ and _____ to the electron transport chain, where ATP is produced from _____.

Answer 25

mitochondria; beta oxidation; acetyl-CoA; hydrogen protons acetyl-CoA; hydrogen atoms; NADH; FADH2; ADP

Question 26

Protein is broken down into _____, which are then converted into _____ to produce ATP.

Answer 26

amino acids; | glucose, pyruvate, or various Krebs cycle intermediates

Question 27

rate-limiting step in the Krebs cycle

Answer 27

conversion of isocitrate to alpha-ketoglutarate

Question 28

The extent to which each of the three energy systems contributes to ATP production depends primarily on the ____ of muscular activity and secondarily on the _____.

Answer 28

intensity; duration

Question 29

_____ is stimulated by ADP and inhibited by ATP.

Answer 29

Isocitrate dehydrogenase

Question 30

The rate of the Krebs cycle is reduced if _____ and _____ are not sufficient to accept _____.

Answer 30

NAD+; FAD2+; hydrogen

Question 31

ETC is stimulated by _____ and inhibited by _____.

Answer 31

ADP; ATP

Question 32

LT represents an increasing reliance on _____.

Answer 32

anaerobic mechanisms

Question 33

Glycolysis from one molecule of blood glucose yields a net of _____ ATP molecules.

Answer 33

2

Question 34

Glycolysis from one molecule of muscle glycogen yields a net of _____ ATP molecules.

Answer 34

3

Question 35

effect of event duration and intensity on primary energy system used

Answer 35

check notes

Question 36

complete ATP resynthesis: _____ | complete CP resynthesis: _____

Answer 36

3 - 5 minutes; < 8 minutes

Question 37

Creatine phosphate (CP) can decreased markedly (_____) during the first stage of high-intensity exercise of short and moderate duration (_____) and can be almost completely depleted as a result of very intense exercise to exhaustion.

Answer 37

50 - 70%; 5 - 30s

Question 38

The rate of glycogen depletion is related to _____.

Answer 38

the exercise intensity

Question 39

Repletion of muscle glycogen during recovery is related to _____. _____ of carbs per kg of bodyweight ingested every 2 hours following exercise.

Answer 39

post exercise carbohydrate ingestion; 0.7 - 3g

Question 40

substantially decrease in blood glucose concentration: long-term exercise ( > _____) at higher intensities (> _____); because of _____

Answer 40

90min; 50% of maximal oxygen uptake; liver glycogen depletion

Question 41

Muscle glycogen is a more important energy source than liver glycogen during _____ exercise.

Answer 41

moderate- and high-intensity

Question 42

bioenergetic limiting factors in exercise performance:

Answer 42

1. ATP and creatine phosphate 2. muscle glycogen 3. liver glycogen 4. fat stores 5. lower pH

Question 43

EPOC

Answer 43

excess postexercise oxygen consumption: the oxygen uptake above resting resting values used to restore the body to the preexercise condition; also called postexercise oxygen uptake, oxygen debt, or recovery O2

Question 44

6 factors responsible for EPOC

Answer 44

1. replenishment of oxygen in blood and muscle 2. ATP/CP resynthesis 3. increased body temperature, circulation, and ventilation 4. increased rate of triglyceride-fatty acid cycling 5. increased protein turnover 6. changes in energy efficiency during recovery

Question 45

400 hurdles/sprint: average time: primary system used:

Answer 45

< 1min | fast glycolysis

Question 46

Oxidative phosphorylation accounts for over _____ of ATP synthesis.

Answer 46

90%

Question 47

At rest, approximately _____ of the ATP produced is derived from fats and _____ from carbohydrate. During high-intensity aerobic exercise, almost _____ of the energy is derived from carbohydrate if an adequate supply is available.

Answer 47

70%; 30% 100%