Excitation Contraction Coupling

Q.

What is the role of the sarcoplasmic reticulum in muscle contraction?

Q. Tropomyosin is found on myosin whereas, troponin is found on actin filament.

1. True
2. False

Q. Sarcolemma is

1. The cytoplasm of striated muscle is called endoplasm.

2. Smooth muscles are found in urinary bladder

3. A striated muscle is a syncytium i.e., a multinudeate structure.

4. The plasma membrane and ER of striated muscles are called sarcolemma and sarcoplasmic reticulum
   respectively.

Q.

In the resting muscle fiber, tropomyosin partially covers

1. Calcium-binding sites on troponin

2. Actin binding sites on myosin

3. Myosin binding sites on actin

4. Calcium-binding sites on actin

Q.

How is the masking of active sites for myosin eliminated?

Q.

The generation of excitation–contraction coupling involves all the following events except

1. Hydrolysis of ATP to ADP

2. Conformational change in troponin

3. Release of calcium from troponin

4. Formation of cross–linkages between actin and myosin

Q. What are the bands that define the ends of each sarcomere called?

1. Actin
2. Myosin
3. Z-Line
4. Sarcoplasmic Reticulum

Q. Which of the following is/are a function(s) of sarcoplasmic reticulum?

1. Store calcium
2. Release calcium
3. Allow impulses to permeate the cell membrane
4. None of the above

Q. What is the function of ER and centrioles

Q.

what do you mean by tonicity??

Q. Name the ion responsible for unmasking of active sites for myosin for cross-bridge activity during muscle contraction

1. Potassium.
2. Calcium
3. Magnesium
4. Sodium.

Q. In a skeletal muscle, T – tubules

1. Secrete acetylcholine
2. Gives mechanical support
3. Conducts impulses forward
4. Bring about calcium flow for muscle contraction

Q. In a skeletal muscle, T – tubules

1. Secrete acetylcholine
2. Bring about calcium flow for muscle contraction
3. Gives mechanical support
4. Conducts impulses forward

Q.

Which of the following statements is not correct?

1. Action potential travels down a T tubule it causes a voltage sensitive protein to change shape. this change shape opens the calcium release channel.

2. Triads in skeletal muscle consist of 2 T-tubules and a cisternae

3. Action potentials are converted into contractions

4. Action potentials travel into the interior of the muscle fiber by T tubules

Q.

Which ion is essential for muscle contraction?

1. Na

2. Cl

3. K

4. Ca

Q.

At the neuromuscular junction, nerve impulses are carried across synaptic cleft by neurotransmitters.

1. sarcoplasm, sarcoplasmic reticulum, calcium ions

2. sarcoplasmic reticulum, terminal cisternae, sarcoplasm

Q. Which of the following is not an effect of ageing in men?

1. Enlargement of muscles due to decreased excercise
2. Decline in capacity of urinary bladder
3. Decline in cell volume
4. Enlargement of heart

Q. In a skeletal muscle, T – tubules

1. Gives mechanical support
2. Secrete acetylcholine
3. Conducts impulses forward
4. Bring about calcium flow for muscle contraction

Q. What is hyaluronic acid

Q. Which of the following is/are a function(s) of sarcoplasmic reticulum?

1. Store calcium
2. Release calcium
3. Allow impulses to permeate the cell membrane
4. None of the above

Q. Which of the following is/are a function(s) of sarcoplasmic reticulum?

1. Store calcium
2. Release calcium
3. Allow impulses to permeate the cell membrane
4. None of the above