Which is not the correct difference between white and red...

Which is not the correct difference between white and red muscle fibres? $\begin{array}{ll}\text { White muscle fibre } & \text { Red muscle fibre }\end{array}$ 1. Less myoglobin $-$ 1. More myglobin 2. Number of mitochondria is less - 2. Number of mitochondria is more 3. Amount of sarcoplasmic reticulum is low $-3$. Amount of sarcoplasmic reticulum is high 4. Aerobic muscle $-4$. Anaerobic muscle (a) 1 (b) 2 (c) 3 (d) 4

Which is not the correct difference between white and red muscle fibres? $\begin{array}{ll}\text { White muscle fibre } & \text { Red muscle fibre }\end{array}$
1. Less myoglobin $-$ 1. More myglobin
2. Number of mitochondria is less
- 2. Number of mitochondria is more
3. Amount of sarcoplasmic reticulum is low $-3$. Amount of sarcoplasmic reticulum is high
4. Aerobic muscle $-4$. Anaerobic muscle
(a) 1
(b) 2
(c) 3
(d) 4

Key Concepts

Muscle Fiber Types

Muscle fiber types refer to the two primary kinds of skeletal muscle fibers: red (slow-twitch) and white (fast-twitch). Red fibers are adapted for endurance and continuous, sustained activity, while white fibers are geared towards quick, powerful contractions and are more suited to anaerobic metabolism.

Myoglobin Content

Myoglobin is an oxygen-binding protein that is abundant in red muscle fibers, giving them their darker color and supporting aerobic respiration. White fibers contain lower levels of myoglobin, limiting their ability to store and use oxygen efficiently.

Mitochondrial Density

Mitochondria are crucial for energy production through aerobic metabolism. Red muscle fibers are rich in mitochondria, which supports prolonged, endurance-based activities, whereas white fibers have fewer mitochondria, reinforcing their reliance on anaerobic processes.

Sarcoplasmic Reticulum

The sarcoplasmic reticulum is the specialized endoplasmic reticulum in muscle cells that stores and releases calcium to trigger muscle contractions. Variation in the amount and efficiency of the sarcoplasmic reticulum between muscle fiber types can affect the speed and force of contractions.

Aerobic vs Anaerobic Metabolism

Aerobic metabolism requires oxygen and is prominent in red muscle fibers, enabling sustained energy production for endurance activities. In contrast, anaerobic metabolism, which does not rely on oxygen, is more common in white muscle fibers, providing quick, explosive energy for short durations.

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