Exemplar Problems
Question 3
Write the difference between :
(a) Actin and Myosin
(b) Red and White muscles
(c) Pectoral and Pelvic girdle
(a) Actin vs. Myosin
| Characteristic | Actin | Myosin |
|---|---|---|
| Type of Protein | Thin filaments | Thick filaments |
| Structure | Composed of actin protein; has binding sites for myosin | Composed of myosin protein; has heads that bind to actin |
| Function | Involved in muscle contraction; slides past myosin during contraction | Pulls actin filaments during contraction; contains ATPase activity |
| Location | Attached to the Z line in a sarcomere | Located in the center of the sarcomere |
| Role in Contraction | Forms the backbone of the thin filament; pulled by myosin | Generates force for muscle contraction; acts as a motor protein |
(b) Red vs. White Muscles
| Characteristic | Red Muscles | White Muscles |
|---|---|---|
| Color | Darker due to higher myoglobin content | Lighter due to lower myoglobin content |
| Fiber Type | Type I (slow-twitch fibers) | Type II (fast-twitch fibers) |
| Energy Source | Aerobic respiration (oxygen-dependent) | Anaerobic respiration (less oxygen-dependent) |
| Endurance | High endurance; resistant to fatigue | Low endurance; tires quickly |
| Function | Suited for prolonged, continuous activities like endurance running | Suited for short, explosive activities like sprinting |
| Examples | Muscles of posture, marathon runners’ muscles | Muscles for quick, powerful movements like jumping |
(c) Pectoral vs. Pelvic Girdle
| Characteristic | Pectoral Girdle (Shoulders) | Pelvic Girdle (Hips) |
|---|---|---|
| Components | Clavicles and scapulae | Hip bones (ilium, ischium, and pubis) |
| Connection to Spine | Attached to the axial skeleton via muscles only | Directly articulates with the sacrum of the spine |
| Range of Motion | Greater range of motion for arm movement | Less range of motion; provides stability |
| Function | Supports arm movements, provides attachment points for muscles | Supports lower body weight, provides attachment points for lower body muscles |
| Stability vs. Mobility | More mobile, less stable | More stable, less mobile |
| Importance in Locomotion | Important for arm and upper body movements | Critical for weight-bearing and leg movements |
BETA
