Chapter 10 (Muscular Tissue VIII)

Question 1

A huge amount of ATP is needed to:

Answer 1

Power the contraction cycle

Pump Ca++ into the SR

Question 2

Production of ATP in Muscle Fibers

Answer 2

The ATP inside muscle fibers will power contraction for only a few seconds
ATP must be produced by the muscle fiber after reserves are used up

Question 3

Muscle fibers have three ways to produce ATP

Answer 3

1) From creatine phosphate
2) By anaerobic cellular respiration
3) By aerobic cellular respiration

Question 4

Creatine Phosphate

Answer 4

Excess ATP is used to synthesize creatine phosphate
Energy-rich molecule
Creatine phosphate transfers its high energy phosphate group to ADP regenerating new ATP
Creatine phosphate and ATP provide enough energy for contraction for about 15 seconds

Question 5

Anaerobic Respiration

Answer 5

Series of ATP producing reactions that do not require oxygen
Glucose is used to generate ATP when the supply of creatine phosphate is depleted
Glucose is derived from the blood and from glycogen stored in muscle fibers
Glycolysis breaks down glucose into molecules of pyruvic acid and produces two molecules of ATP
If sufficient oxygen is present, pyruvic acid formed by glycolysis enters aerobic respiration pathways producing a large amount of ATP
If oxygen levels are low, anaerobic reactions convert pyruvic acid to lactic acid which is carried away by the blood
Anaerobic respiration can provide enough energy for about 30 to 40 seconds of muscle activity

Question 6

Aerobic Respiration

Answer 6

Activity that lasts longer than half a minute depends on aerobic respiration
Pyruvic acid entering the mitochondria is completely oxidized generating ATP, carbon dioxide, Water and Heat
Each molecule of glucose yields about 36 molecules of ATP
Muscle tissue has two sources of oxygen
Myoglobin and hemoglobin are oxygen-binding proteins
Aerobic respiration supplies ATP for prolonged activity
Aerobic respiration provides more than 90% of the needed ATP in activities lasting more than 10 minutes

Question 7

Muscle tissue has two sources of oxygen

Answer 7

1) Oxygen from hemoglobin in the blood

2) Oxygen released by myoglobin in the muscle cell