Understanding Skeletal Muscle Fibers

What are the two main types of skeletal muscle fibers?

• Actin and Myosin

• Red and White

• Type I and Type II

• Slow-twitch and Fast-twitch

Which type of muscle fiber is characterized by slower contraction and higher fatigue resistance?

• Type IIa

• Type III

• Type I

• Type IIb

What is the primary energy source for Type I muscle fibers?

• Lipid metabolism

• Protein synthesis

• Oxidative phosphorylation

• Anaerobic glycolysis

Which muscle fiber type has the highest glycogen content?

• Type IIa

• Type I

• Type III

• Type IIb

How do fast-twitch fibers generally produce energy?

• None of the above

• Both A and B

• Anaerobic glycolysis

• Oxidative phosphorylation

What role does myoglobin play in muscle fibers?

• Protein breakdown

• Oxygen storage

• ATP synthesis

• Glycogen storage

Which muscle fiber type is known as 'Fast Glycolytic fibers'?

• Type I

• Type IIa

• Type III

• Type IIb

What is the main characteristic that distinguishes Type IIa fibers from Type IIb fibers?

• Color

• Oxidative capacity

• Speed of contraction

• Myosin ATPase activity

What is the primary function of mitochondria in muscle fibers?

• Myoglobin production

• ATP production through oxidative phosphorylation

• Protein synthesis

• Glycogen storage

Which type of muscle fibers are predominant in muscles used for marathon running?

• Type IIa

• Type IIb

• Type III

• Type I