Tag: biology

Questions Related to biology

Dark bands are :

biology locomotion and movements structure of muscle skeletal muscles coordination

  1. A-band

  2. B-band

  3. I-band

  4. Z--line

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Correct Option: A
Explanation:
A-bands in muscles are the dark bands that are located in the regions where thick myosin filaments are present.
So, the correct answer is 'A-band'.

The functional unit of contractile system in a striated muscle is 

biology locomotion and movements structure of muscle skeletal muscles coordination

  1. sarcomere

  2. Z-band

  3. cross bridges

  4. myofibril

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Correct Option: A
Explanation:

The sarcomeres are fibrous protein filaments that slide past one another when the muscle contracts or relaxes. It is basically the region between two Z-bands. It is also the functional unit of the contractile system in a striated muscle.

So, the correct answer is 'sarcomere'.

Read the given statements and select the correct option.
Statement 1 : A primary myofilament is composed of a bundle of rod-like molecules of a protein myosin.
Statement 2 : Myosin and actin together form a contractile apparatus. 

biology locomotion and movements structure of muscle skeletal muscles coordination

  1. Both statements 1 and 2 are correct.

  2. Statement 1 is correct but statement 2 is incorrect.

  3. Statement 1 is incorrect but statement 2 is correct.

  4. Both statements 1 and 2 are incorrect.

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Correct Option: A
Explanation:
Both the statements given in the question are correct as a primary myofilament is composed of a bundle of rod-like molecules of a protein myosin and myosin and actin together form a contractile apparatus.
So, the correct answer is '
Both statements 1 and 2 are correct.'

Each myofibril has a diameter of.

biology locomotion and movements structure of muscle skeletal muscles coordination

  1. $1$ to $2$ $\mu$m

  2. $0.1$ to $0.2$ $\mu$m

  3. $.001$ to $.002$ $\mu$m

  4. None of the above

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Correct Option: A

Myosin filaments are thick and are made up of small units called meromyosin. Each meromyosin globular head with short arm called ____________.

biology locomotion and movements structure of muscle skeletal muscles coordination

  1. Heavy meromyosin

  2. Light meromycin

  3. Both a and b

  4. None of these

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Correct Option: A

Which of the.following statements are correct regarding muscle proteins ?
 (i) Actin is a thin filament and is Frock up of two F-actirs.
(ii) The complex protein, tropomyosin is distributed at regular intervals on the troponin. 
(iii)  Myosin is a thick flament which is also a polymerised protein. 
(iv) The globular head of meromyosin consists of light merornyosin (LMM).

biology locomotion and movements structure of muscle skeletal muscles coordination

  1. (i), (ii) and (iii)

  2. (i), (ii) and (iv)

  3. (i) and (iii)

  4. (ii) and (iv)

Show answer
Correct Option: A
Explanation:

Actin is the thin filament in the sarcomere, comprising F-actin, tropomyosin and troponin protein, troponin is attached to tropomyosin, while myosin is a thick filament.

So, the correct option is '(i), (ii) and (iii)'.

Which of the following is called as the response?

biology neural control and coordination structure of muscle skeletal muscles locomotion and movements

  1. Drawing out the hand

  2. Pricking with the pin

  3. Pin in the box

  4. Hand in the pocket

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Correct Option: A
Explanation:

A stimulus is something that causes a physiological response. The ability of an organism or organ to respond to external stimuli is called sensitivity. So, in the above example, the response to stimulus is drawing out hand and not pricking with pin, only pin or hand.

Therefore, the correct answer is option A.

When you are pricked with a pin, you will draw out your hand very fast. The stimulus is 

biology neural control and coordination structure of muscle skeletal muscles locomotion and movements

  1. Drawing out hand

  2. Pricking with a pin

  3. Pin

  4. Hand

Show answer
Correct Option: B
Explanation:

A stimulus is something that causes a physiological response. The ability of an organism or organ to respond to external stimuli is called sensitivity. So, in the above example, the stimulus is pricking with pin and not drawing out hand, only pin or hand. 

Therefore, the correct answer is option B.

Internal stimulus comes from

biology neural control and coordination structure of muscle skeletal muscles locomotion and movements

  1. Inside an organism

  2. Outside an organism

  3. Skin

  4. None of the above

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Correct Option: A
Explanation:

  • In physiology, a stimulus is a detectable change in the internal or external environment. The ability of an organism or organ to respond to external stimuli is called sensitivity. 
  • When a stimulus is applied to a sensory receptor, it normally elicits or influences a reflex. Hence, Internal stimulus comes from
Inside an organism.
 So, the correct answer is 'Inside an organism'.

Behaviour that involves an external stimulus triggering a genetically determined response is called as

biology neural control and coordination structure of muscle skeletal muscles locomotion and movements

  1. True

  2. False

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Correct Option: B
Explanation:

The fixed action patterns to specific stimuli which activate nervous system making the muscular action without any involvement of brain in decision making are known as innate behaviours. Being genetically determined, these responses are nearly alike in all members of a population. 

Learning (learned behaviour) is a modification of innate behaviour as a result of specific experiences and involves the formation of memories by changes in neural connectivity.
A form of learning that occurs during a brief genetically determined critical period shortly after birth is called as imprinting. 
Conditioned is also a learned response in which stimulus becomes associated with a consequence. 
Hence, the correct answer is option A.