Tag: biology

Questions Related to biology

One myosin filament in the myofibril of skeletal muscle fibre is surrounded by how many actin filaments?

biology multicellular structure: tissue muscle tissue structure of protein muscle tissues

  1. Two

  2. Four

  3. Six

  4. Three

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Correct Option: C
Explanation:

Six actin filaments surround each myosin filament and the active sites of an actin filament are available to three different myosin filaments in the myofibril of skeletal muscle fibre.

The type of muscle present in our 

biology animal tissue muscle tissue structure of protein muscle tissues

  1. Heart is Involuntary and unstriated smooth muscle

  2. Intestine is striated and involuntary

  3. Thigh is striated and voluntary

  4. Upper arm is smooth muscle and fusiform in shape

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Correct Option: C

Cardiac muscle fibres are _____________.

biology animal tissue muscle tissue structure of protein muscle tissues

  1. Striated involuntary

  2. Striated voluntary

  3. Non-striated involuntary

  4. Non-striated voluntary

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Correct Option: A
Explanation:

Cardiac muscles are striated involuntary, Contract quickly and do not get fatigued.

In heart cells, which one serves as a second messenger, speeding up muscle cell contraction in response to adrenaline _____________.

biology animal tissue muscle tissue structure of protein muscle tissues

  1. cAMP

  2. cGMP

  3. GTP

  4. ATP

  5. AMP

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Correct Option: A

Which of the following is a fusiform muscle ?

biology animal tissue muscle tissue structure of protein muscle tissues

  1. Cardiac muscle

  2. Smooth muscle

  3. Intercalated disc

  4. All of these

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Correct Option: A

Which of the following muscle fibres do not show striation and taper at both ends?

biology animal tissue muscle tissue structure of protein muscle tissues

  1. Cardiac muscle fibres

  2. Smooth muscle fibres

  3. Skeletal muscle fibres

  4. Voluntary muscle fibres

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Correct Option: A

Choose the correct answer from the alternatives given.
Which of the following tissues is most affected due to the deficiency of oxygen? 

biology animal tissue muscle tissue structure of protein muscle tissues

  1. Cardiac muscles

  2. Visceral muscles

  3. Hyaline cartilage

  4. Long bones

Show answer
Correct Option: A
Explanation:

When oxygen demand increases, heart rate and cardiac output increase, which increases the flow of blood through the lung and the pressure required to force blood through the arterioles and capillaries of the lung. Due to this, the cardiac muscles are most affected due to deficiency of oxygen. So, the correct option is 'Cardiac muscles'.

One amongst the following is not a property of cardiac muscle fibres

biology animal tissue muscle tissue structure of protein muscle tissues

  1. Their T- tubules occur at the level of Z - discs

  2. They are innervated by branches from cranial and spinal nerves

  3. Striated in appearance

  4. Their refractory period is longest

Show answer
Correct Option: A
Explanation:
Cardiac muscle fibres are involuntary and striated in appearance, which is present in the heart. The main characteristic of this is they initiate their rhythmic impulses. Their refractory period is the longest. This type of muscle fibres is innervated by branches from cranial and spinal nerves. Skeletal muscle contains Z-discs to connect the one muscle fibre from another muscle fibres. But cardiac muscle fibres do not contain Z-disc
Thus, the correct answer is 'Their T- tubules occur at the level of Z - discs.'

Which muscles having functionally multinucleated conditions?

biology animal tissue muscle tissue structure of protein muscle tissues

  1. Cardiac muscle

  2. Smooth muscle

  3. Voluntary muscle

  4. All of these

Show answer
Correct Option: A
Explanation:

Skeletal muscle cells are multinucleated from the fusion of muscle cells. Smooth muscle cells are strictly mononucleated, and cardiac muscle cells are mononucleated in humans. However, cardiac muscle cells are functionally syncytium. They have their cells interconnected with gap junctions, which allow rapid co-ordinated contraction of the muscle cells. The cells, however, are not multinucleated and are not true syncytium (as seen in case of skeletal muscle) but functionally they are syncytium (multinucleated). Therefore, cardiac muscle is functionally multinucleated and skeletal (voluntary) muscle are true multinucleated. So, the correct option is 'Cardiac muscle'.

Skeletal muscles are controlled by?

biology animal tissue muscle tissue structure of protein muscle tissues

  1. Sympathetic nervous system

  2. Parasympathetic nervous system

  3. Somatic nervous system

  4. Sympathetic and parasympathetic both

Show answer
Correct Option: C
Explanation:
  • The somatic nervous system is the part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles. The somatic nervous system consists of afferent nerves or sensory nerves, and efferent nerves or motor nerves.
  • Skeletal muscle is a form of striated muscle tissue, which is under the voluntary control of the somatic nervous system. 
  • Hence Skeletal muscles are controlled by Somatic nervous system.
  • So, the correct answer is 'Somatic nervous system'.