Chapter 3: Bioenergetics

Question 1

Define bioenergetics

Answer 1

The conversion of macronutrients into usable forms of energy

Question 2

Catabolism

Answer 2

The breakdown of molecules resulting in a release of energy

Question 3

Anabolism

Answer 3

The synthesis of larger molecules. Requires energy

Question 4

What are the two types of reactions?

Answer 4

Exergonic and endergonic reactions

Question 5

What are Exergonic reaction?

Answer 5

energy-releasing reactions. Catabolism

Question 6

What are endergonic reactions

Answer 6

requires energy. anabolism

Question 7

What is left after ADP hydrolysis?

Answer 7

ADP –> AMP, P, and H

Question 8

Phosphagen System: Key points 1

Answer 8

The synthesis of CP and ADP to form ATP. Catalyzed by CK

Question 9

Phosphagen System:
Key points 2

Answer 9

Uses CK reactions to maintain ATP concentration

Question 10

What law controls the phosphagen system?

Answer 10

Law of mass action: The concentration of the reactants or products drive the direction of the reaction
(i.e. increased ADP causes an increase in ADP rephosphorylation into ATP by CP)

Question 11

Glycolysis System:
Key point 1

Answer 11

Breakdown of Carbs to resynthesize ATP

Question 12

What is the end product of glycolysis? And what is its “fate”?

Answer 12

Pyruvate.
-Can either be converted into lactate and enter fast glycolysis
-Or get shuttle to the mitochondria into the krebs cycle and undergo slow glycolysis

Question 13

“slow” vs “fast” glycolysis

Answer 13

Fast: ATP resynthesis occurs at faster rate but doesn’t last as long
Slow: ATP resynthesis occurs at a slower rate but lasts longer

Question 14

What is involved in the Cori cycle?

Answer 14

The conversion of lactate into glucose in the liver

Question 15

What is the energy yield after glycolysis?

Answer 15

Glucose –> 2
Glycogen –> 3

Question 16

What occurs in the slow glycolysis?

Answer 16

Pyruvate converted into Acetyl-Coa and enters the krebs cycles.
NADH molecules enter the ETC for further resynthesis of ATP

Question 17

What is lactate threshold?

Answer 17

The exercise intensity or % VO2 max where an abrupt increase in lactate is seen

Question 18

What does the lactate threshold represent?

Answer 18

an increased reliance on anaerobic mechanisms

Question 19

What is Onset blood lactate accumulation (OBLA)

Answer 19

The second marker of an abrupt increase in lactate (~ 4 mmol/l)

Question 20

What is the lactate threshold for untrained vs trained individuals?

Answer 20

50-60% vs 70 to 80%

Question 21

The oxidative system: Key points 1

Answer 21

Primarily fueled by CHO and fats

Question 22

Describe fat oxidation

Answer 22

Triglycerides are broken down into free fatty acids by hormone sensitive lipase. The free fatty acids then undergo beta oxidation in the mitochondria of the muscle fibers and are converted into acetyl- CoA and H. Acetyl-CoA enters the krebs cycle and H atoms are carried by NADH and FADH2 into the ETC

Question 23

Protein oxidation

Answer 23

Broken down in amino acids and converted into glucose, pyruvate of enter into Krebs cycles

Question 23

What controls the oxidative system?

Answer 23

-Isocitrate dehydrogenase is stimulated by ADP and inhibited by ATP
- the rate of the Krebs cycle is determine by the availability of NAD and FAD
- the ETC is stimulated by ADP and inhibited by ATP

Question 24

Phosphagens: CP depletion

Answer 24

• CP decrease 50-70% during the fist stage of high-intensity exercise. Can almost be eliminated during very intense exercise to exhaustion

Question 25

Phosphagens: Repletion

Answer 25

-CP = 8 min
-ATP = 3-5 min

Question 26

Glycogen Depletion

Answer 26

The rate is related to exercise intensities. Can become completely deplete in muscle cells during exercise

Question 27

Glycogen repletion

Answer 27

Comes from food. Aim for 0.7 to 3 g per kg ever 2 hours