OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

How do the knee and elbow joints primarily differ in function?

1. Their composition of ligaments

2. The type of movements they produce

3. The mechanism of muscle contraction

4. Their stabilization process

The correct answer is: The mechanism of muscle contraction

The primary difference in function between the knee and elbow joints lies in the type of movements they produce. The knee joint is primarily a hinge joint that allows for flexion and extension, enabling movements such as walking, running, and jumping. In contrast, the elbow joint, also a hinge joint, allows for flexion and extension but is primarily involved in movements like lifting and throwing. Focusing on the type of movements helps clarify the key functional distinctions: the knee is instrumental for weight-bearing activities and pivoting, while the elbow facilitates actions involving the forearm and hand. This difference in function is crucial for understanding how these joints interact with muscles and other parts of the body during various physical activities. While the composition of ligaments, stabilization processes, and mechanisms of muscle contraction play roles in the overall functioning of these joints, they do not define the fundamental way that the knee and elbow joints differ regarding their primary functions.