Final Exam Chapter 12 review

Question 1

What is the role of creatine phosphate during ATP production? And when ATP is not being used?

Answer 1

It basically gives its ATP to ADP to get a faster ATP production

When ATP is not being used the ATP gives a phosphate group to creatine for it to be stored and used for later

Question 2

What energy source do muscles use at rest, moderate exercise, and during peak activity?

Answer 2

Rest: fatty acids

Moderate exercise: glycogen

Peak activity: creatine phosphate

Question 3

What are the 5 steps of initiation (excitation)?

Answer 3

1. An action potential arrives at the axon terminal
2. Triggers Ca2+ voltage gated channels to open and triggers the release of acetylcholine from synaptic vesicles
3. Triggers Ca2+ voltage gated channels open and triggers the release of acetylcholine from synaptic vesicles
4. ACh diffuses across the synaptic cleft and binds to its receptors on the sarcolemma, Na+ gated channels open and does depolarization
5. AChE breaks down ACh to end the electrical current. Acetate and choline is broken down and choline is taken back up to the presynaptic membrane`

Question 4

What is the role of troponin and tropomyosin? (functions)

Answer 4

Troponin: attaches to tropomyosin and Blocks the binding of actin to myosin

Tropomyosin: Wraps around the actin and controls the movement of troponin and blocks the myosin active site when relaxed

Question 5

How does calcium play a role in the functions of troponin and tropomyosin?

Answer 5

When calcium binds to troponin then it moves the tropomyosin away from the binding site of actin. When the calcium leaves the troponin the tropomyosin moves back onto the active sites of the actin.

Question 6

What are the 3 steps of the excitation-contraction coupling?

Answer 6

1. Electrical impulses (depolarization) triggers the release of calcium from the sarcoplasmic reticulum into the sarcoplasm
2. Calcium binds to the troponin changing its conformation and rotates tropomyosin away from the myosin binding sites
3. Actin and myosin are free to interact and form a crossbridge

Question 7

What are the 3 steps of the sliding filament theory?

Answer 7

1. Stored energy from the resting position allows the myosin head to pivot toward the M-line which pulls the actin filament with it
2. ATP binds to the myosin head causing it to release and break the crossbridge with the actin filament
3. Myosin uses ATP to reposition its head to prepare for another cycle

Question 8

What is the location and function of Myoglobin?

Answer 8

Location: In the sarcoplasm

Function: Stores oxygen needed for muscular activity (red pigment)