Tendons through which muscles are connected to bones are tightly compacted bundles of which one of the following long fibrous protein?
- A.Fibrin
- B.Collagen
- C.Elastin
- D.Cellulose
Correct answer
Explanation
The correct answer is B, Collagen. Tendons are made of tightly packed parallel bundles of collagen fibres, which give them great pulling strength.
Collagen is the most abundant protein in the human body. Its molecules are three chains twisted into a rope-like triple helix, and many of them line up to form strong fibres that resist stretching. Tendons use this to pass the pull of a contracting muscle to the bone without giving way. The Achilles tendon, joining the calf muscle to the heel, is the largest tendon in the body. Ligaments, which join bone to bone, are also mainly collagen but carry more elastin.
A is wrong because fibrin is the protein that forms the mesh of a blood clot.
C is wrong because elastin is the stretchy protein of skin, lungs and artery walls.
D is wrong because cellulose is a carbohydrate of plant cell walls, not a protein.
Exam tip: tendon = muscle to bone, ligament = bone to bone; both are collagen-rich connective tissue.
Practice Questions
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- B.1 s
- C.1.5 s
- D.2 s
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