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29 Cards in this Set

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to enable continued contraction
Why is it necessary for muscle to have mechanisms to make ATP quickly?
b. Exposure of the myosin binding sites on actin.
Which of these is not an important role of ATP in skeletal muscle contraction?
a. Disconnecting the myosin cross bridge from the binding site on actin at the conclusion of a power stroke.
b. Exposure of the myosin binding sites on actin.
c. Energizing the power stroke of the myosin cross bridge.
d. Energizing the calcium ion pump which actively transports calcium ions back into the sarcoplasmic reticulum.
c. ammonia
Which of these is not a part of the ATP molecule?
a. adenine nucleotide
b. phosphate groups
c. ammonia
d. high energy phosphate bonds
H2O, ADP + Pi + energy
Fill in the blanks in the following equation for the hydrolysis of ATP.

ATP + ______ → ______ +______ + _______
Because the water breaks down the high energy bond btwn. the last phosphate group. The H20 breaks down ATP into ADP & Pi.
Why is the reaction that releases energy from ATP termed a "hydrolysis" reaction?
H20
Give a specific example of a hydrolytic enzyme that hydrolyzes ATP into ADP and Pi in muscle cells.
ADP + Pi + energy → H20 + ATP
Fill in the blanks in the following equation for the dehydration synthesis of ATP.

_____+ ______+______ → ______ + ATP
Because the water is removed and a bigger molecule is synthesized from 2 smaller ones.
Why is the production of ATP from ADP termed a "dehydration synthesis" reaction?
Because energy is released & like "currency" can be "spent" for moving myofilaments & transporting ions
Why is ATP often called "energy currency"?
seconds
Muscle cells have only enough ATP to last for ____________ during an active contraction period.
1. Hydrolysis of creatine phosphate
2. Glycolysis
3. Kreb's cycle
List three processes that muscle cells use to make ATP when it is needed for muscle contraction.
creatine phosphate
What is the most immediate source of energy for rebuilding ATP within muscle cells?
creatine phosphate
ADP
creatine
ATP
Fill in the following blanks to show the production of ATP from Creatine phosphate:
______________ + _____________ → ______________ + ______________
1. directly from
2. produced by hydrolysis of glycogen stored in the muscle cell.
What are the two sources of glucose to muscle cells?
1. 2 ATP molecules
2. pyruvic acid
What are the end products of glycolysis?
converted to lactid acid
What happens to pyruvic acid in the absence of oxygen?
leads to muscle fatigue
What happens if a muscle is deprived of oxygen for too long when it is physically active?
myoglobin
What is the name of the oxygen binding protein within muscle?
mitochondria
Where, within a muscle cell, will the Krebs cycle and oxidative phosphorylation occur?
Co2
H20
36 ATP molecules
What are the end products of the aerobic pathway?
2 ATP
36 ATP
The total energy harvest from glycolysis, the Krebs cycle and oxidative phosphorylation is 38 ATP molecules for each glucose molecule metabolized.
a. How much of that ATP is generated during glycolysis?
b. How much of that ATP is generated during the Krebs cycle and oxidative phosphorylation?
a. anaerobic metabolism, because it provides short bursts of ATP
b. aerobic respiration, because there is more ATP provided for a long duration of muscle activity.
During which of these activities would creatine phosphate and anaerobic metabolism be more important. During which of these activities would aerobic respiration (Krebs cycle and oxidative phosphorylation) be more important. Why?
a. very fast sprinting for a short distance
b. slow jogging for a long distance
energy reserves ("oxygen debt")
lactic acid
After the exercise period is concluded, what reserves have been depleted within the muscle cells? In addition, what by-product tends to build-up in the muscle cell?
"oxygen debt"
Lactic acid
ATP
glucose molecules
myoglobin.
To restore the ______________ after exercise, muscle cells convert ________________ ,present in the cytosol, back into pyruvic acid, which enters the Krebs cycle, producing ______________, which is used to re-phosphorylate creatine into creatine phosphate. Glycogen is also synthesized from ______________ and additional oxygen re-binds to ________________.
White muscle fibers & red muscle fibers
What are the names of the two different types of muscle cells?
Few mitochondria
have high glycogen content; light color due to reduced reduced myoglobin
have few capillaries
List several structural features that white muscle cells have that explains why these muscle fibers mainly use glycolysis to synthesize ATP (as opposed to the Krebs cycle and oxidative phosphorylation).
Because it synthesizes ATP quickly & have rapid cross bridge cycling results in fast contractions.
Why are white muscle fibers also called "fast-twitch glycolytic fibers?"
Lots of mitochondria
lots of myoglobin
many capillaries
low glycogen content
List several structural features that red muscle cells have that explains why these muscle fibers mainly use Krebs cycle and oxidative phosphorylation to synthesize ATP (as opposed to anaerobic metabolism).
Because the cross bridge cycling occurs relatively slowly.
Fatigue resistant
high endurance
Why are red muscle fibers also called "slow-twitch oxidative fibers?"