Type I vs Type IIb Muscle Fibers

The video tutorial explores the differences between type 1 and type 2 muscle fibers, focusing on their structure, function, and molecular basis. Type 1 fibers are smaller, suited for endurance activities, and have more mitochondria, making them fatigue-resistant. Type 2 fibers are larger, suited for power activities, and have more myosin ATPase, leading to faster ATP consumption and quicker fatigue. The role of myoglobin, glycogen, and creatine storage in muscle fibers is also discussed, highlighting the metabolic pathways and energy utilization in different fiber types.

Which type of muscle fiber is more suited for endurance activities like long-distance running?

• Type 2D

• Type 2B

• Type 2A

• Type 1

What is the primary role of myosin ATPase in muscle fibers?

• To bind oxygen

• To store glycogen

• To produce lactic acid

• To hydrolyze ATP for muscle contraction

Why do type 2 muscle fibers fatigue faster than type 1 fibers?

• They have more myoglobin

• They produce more ATP

• They have more mitochondria

• They consume ATP faster and produce less

What is the function of myoglobin in muscle fibers?

• To store ATP

• To bind and store oxygen

• To produce glucose

• To catalyze glycolysis

Which type of muscle fiber appears red due to the presence of myoglobin?

• Type 1

• Type 2A

• Type 2B

• Type 2D

What is the role of creatine kinase in muscle fibers?

• To break down glycogen

• To phosphorylate creatine

• To produce lactic acid

• To bind oxygen

Which muscle fiber type is better at storing glycogen?

• Type 1

• Type 2D

• Type 2B

• Type 2A

What is the primary energy system used by type 2 muscle fibers during high-intensity activities?

• Glycolytic metabolism

• Oxidative phosphorylation

• Protein catabolism

• Lipid metabolism

Which type of muscle fiber is often referred to as oxidative fibers?

• Type 1

• Type 2D

• Type 2A

• Type 2B

What is the main reason type 1 fibers are more fatigue-resistant?

• They have more creatine kinase

• They have more myosin

• They store more glycogen

• They have more mitochondria