NEET · Biology · Locomotion & Movement doubts
10 doubts found
What actually happens inside a muscle when it contracts to lift something?
A nerve signal releases calcium ions inside the muscle fibre, which expose binding sites on the thin actin filaments.
Why do the biceps and triceps have to work as a pair to bend and straighten your arm?
A muscle can only actively shorten and pull — it cannot push.
Why does a body become stiff (rigor mortis) some hours after death?
Detaching a myosin head from actin to relax a muscle requires ATP.
Why do your muscles ache and tire during hard exercise, and sometimes cramp?
During intense effort the muscles need more oxygen than the blood can supply, so they switch to anaerobic respiration to keep making ATP.
What does “Sliding filament theory” actually mean in Locomotion & Movement, and why does it matter for NEET?
muscles contract when thin actin filaments slide over thick myosin filaments, shortening the muscle — powered by ATP and triggered by calcium.
I keep getting “Sliding filament theory” questions wrong in Locomotion & Movement. What's the trap?
thinking the filaments themselves shrink.
What does “Antagonistic muscles” actually mean in Locomotion & Movement, and why does it matter for NEET?
muscles work in opposing pairs because a muscle can only pull, not push.
I keep getting “Antagonistic muscles” questions wrong in Locomotion & Movement. What's the trap?
expecting one muscle to both bend and straighten a joint.
What is the difference between actin and myosin?
Actin is the thin filament; myosin is the thick filament whose heads pull on actin. Their sliding overlap shortens the muscle during contraction.
What is the difference between cartilage and bone?
Cartilage is soft, flexible connective tissue (nose, ear, joint surfaces); bone is hard, calcified tissue that supports the body and protects organs.