Question

Slow twitch muscle fibers are darker in color. This is due to:

a) higher levels of mitochondria
b) lower levels of mitochondria
c) high levels of fat
d) none of the above

Answer 1

Slow-twitch muscle fibers are darker in color due to high levels of myoglobin and mitochondria. These fibers can contract for long periods of time but with less force compared to fast-twitch fibers. They are primarily used in endurance activities.

Therefore the correct answer is option is a) higher levels of mitochondria

Step-by-step explanation:

Slow-twitch muscle fibers, also known as type I or oxidative fibers, are darker in color due to their high levels of myoglobin and mitochondria. Myoglobin is a protein that stores oxygen, giving the muscle tissue its characteristic red color.

In addition, slow-twitch fibers are rich in mitochondria, which are responsible for producing energy through aerobic metabolism. These fibers can contract for long periods of time but with less force compared to fast-twitch fibers. They are primarily used in endurance activities such as distance running or cycling.