Chapter 3-Bioenergetics

Question 1

Catabolism

anabolism

exergonic reactions

endergonic reactions

Answer 1

breakdown of larger molecules

building up of molecules

energy releasing reactions

require energy

Question 2

metabolism

Answer 2

total of all the catabolic and anabolic reactions in a biological system

Question 3

hydrolysis

Answer 3

breakdown of 1 molecule of ATP to yield energy

requires one molecule of water

Question 4

anaerobic

Answer 4

phosphagen and glycolytic systems do not require oxygen and occur in the sarcoplasm of the cell

only carbs can be metabolized into energy without the direct involvement of oxygen

Question 5

aerobic

Answer 5

krebs cycle, electron transport, and the rest of the oxidative system require oxygen and occur in the mitochondria of the cells

Question 6

phosphagen system

Answer 6

short-term, high intensity activities
highly active at the start of exercise
relies on hydrolysis and breakdown of creatine phosphate
limited by the small storage of CP

Question 7

law of mass action

Answer 7

the concentrations of reactants or products in solution will drive the direction of the reactions

Question 8

glycolysis

Answer 8

breakdown of either glycogen stores in muscle or glucose from blood to resynthesize ATP
not as rapid, but greater capacity due to greater supply of carbohydrates

Question 9

pyruvate

Answer 9

end result of glycolysis

can be converted to lactate which results in faster resynthesis of ATP

can be shuttled to mitochondria to undergo the Krebs cycle with a shorter resynthesis rate due to greater number of reactions but can occur for longer duration

Question 10

metabolic acidosis

Answer 10

process of an exercise-induced decrease in pH

may be responsible for the peripheral fatigue that occurs during exercise

Question 11

lactate accumulation

Answer 11

normal range is 0.5 to 2.2 mmol/L at rest
increases with exercise intensity

maximal rate of production is twice as much for Type II (0.5 mmol/g/s) compared to Type 1 (0.25 mmol/g/s)

severe fatigue may occur at blood concentrations between 20-25 mmol/L

influenced by exercise intensity, muscle fiber type, exercise duration, state of training and initial glycogen levels

Question 12

ATP yield

Answer 12

substrate-level phosphorylation during glycolysis yields 4 ATP

when it begins with blood glucose, 2 ATP are used, 4 are resynthesized for net gain of 2

when it begins with muscle glycogen, 1 ATP is used, 4 are resynthesized for net yield of 3 ATP

Question 13

Allosteric regulation

allosteric inhibition

allosteric activation

Answer 13

end product of a reaction feeds back to regulate the turnover rate of key enzymes in the metabolic pathways

an end product binds to the regulatory enzyme and decreases its turnover rate and slows product formation

an activator binds with the enzyme and increases its turnover rate

Question 14

regulatory enzymes in glycolysis

Answer 14

hexokinase, PFK and pyruvate kinase

Question 15

Lactate threshold

Answer 15

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

typically begins at 50-60% of maximal oxygen uptake in untrained individuals and 70-80% in aerobically trained athletes

Question 16

OBLA

Answer 16

onset of blood lactate accumulation
second increase in the rate of lactate accumulation noted at higher relative intensities
occurs when the concentration of blood lactate reaches 4 mmol/L

Question 17

oxidative system

Answer 17

primary source of ATP at rest and during low-intensity activities
primarily uses carbs and fats as substrates
at rest, 70% of ATP is from fat and 30% from carbs
as intensity increase, these ratios change
during high-intensity almost 100% of energy comes from carbs

Question 18

oxidative phosphorylation

Answer 18

glycolysis and the Krebs cycle

40 total, but uses 2 ATP for a net gain of 38 ATP

Question 19

phosphagen

Answer 19

concentrations are more rapidly depleted during high-intensity anaerobic exercise
resting concentrations may be increased with training
primary limiting factor during high intensity exercise

Question 20

glycogen

Answer 20

300-400g are stored in muscle, 70-100g in liver
training can increase resting levels

repletion of muscle glycogen during recovery is related to ingestion
optimal levels are 0.7 to 3.0 g carbs per kg body weight every 2 hrs after exercise

Question 21

Interval training

Answer 21

method that emphasizes bioenergetic adaptations for a more efficient energy transfer within the metabolic pathways by using predetermined intervals of exercise and rest

allow for more training at higher intensities

Question 22

which substance can be metabolized anaerobically

Answer 22

glucose

Question 23

the reaction that is the primary cause of metabolic acidosis

Answer 23

breakdown of ATP releasing P and H

Question 24

which energy system produces ATP at the quickest rate

Answer 24

phosphagen

Question 25

how many net ATP are produced via the oxidative energy system from the metabolism of 1 glucose molecule

Answer 25

38

Question 26

which energy substrate cannot be depleted during extreme exercise intensities/durations

Answer 26

ATP