Mechanism of Muscle Contraction

A characteristic feature of the muscle fibre is the presence of a large number of parallelly arranged filaments in the sarcoplasm called

• myofibrils

• sarcomeres

• muscle bundles

• skeletal muscles

The plasma membrane of of a muscle fibre is called as

• Sarcoplasm

• Sarcoplasmic reticulum

• Sarcomere

• Sarcolemma

I- band is made up of

• Myosin filaments

• Actin filaments

• Troponin

• Tropomyosin

Dark band that contains myosin filaments is called I- band.

• True

• False

The thin filaments are firmly attached to

• M- line

• A-line

• Z- line

• I-line

Which of the following best defines a sarcomere unit?

• The portion of the myofibril between two successive ‘Z’ lines is considered as the functional unit of contraction and is called a sarcomere

• The portion of the myofibril between two successive ‘M’ lines is considered as the functional unit of contraction and is called a sarcomere

• The portion of the myofibril between two successive I- bands is considered as the functional unit of contraction and is called a sarcomere

• The portion of the myofibril between two successive A-bands is considered as the functional unit of contraction and is called a sarcomere

Tags

NGSS.MS-LS1-3

Which of the following is the correct sequence of organization of skeletal muscle?

• Skeletal muscle - muscle fibre- muscle bundle - myofibril - sarcomere

• Skeletal muscle - muscle bundle- muscle fibre- myofibril - sarcomere

• Muscle bundle- muscle fibre- skeletal muscle- myofibril - sarcomere

• Skeletal muscle - muscle bundle- myofibril- muscle fibre- sarcomere

Tags

NGSS.HS-LS1-2

The contractile protein represented here is

• Myosin

• Actin

The contractile protein represented here is

• Actin

• Myosin

In the resting state of a sarcomere, a subunit of ___________ masks the active binding sites for myosin on the actin filaments

• Tropomyosin

• F actin

• G actin

• Troponin