Biology · General Awareness

Muscle Biology

798 Questions

Muscle biology covers the structures, functions, and contraction mechanisms of skeletal, cardiac, and smooth muscles. Test questions target filaments, stimuli, and specific muscle roles. A clear understanding helps secure marks in biology sections.

Skeletal muscle controlCardiac muscle propertiesMuscle contraction mechanismActin and myosin filamentsMuscle functions

Muscle Biology Questions

Multiple choice zoology skeleton and joints introduction to movement introduction to locomotion movement

Which of the following parts of the body moves by using muscular force?

  1. Biceps

  2. Legs

  3. Jaws

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A muscle is a tissue composed of cells or fibers, the contraction of which produces movement in the body. Muscular force is needed to bring movement, which needs energy for the contraction and relaxation of the same. Muscles are attached to bones to bring about the required movement.

The biceps are the muscles present in the upper arms, which require muscular force for its movement.
The legs are consist of bones attached to muscles which require muscular force for movement.
Jaws i.e. the mandibular region also requires muscular force to cause movement, because the muscles attached need force for resulting in movement.
Thus, the correct answer is 'All of the above'.

Multiple choice biology our skeletal system and the skin other systems in the body introduction to skeletal system busy at work - our internal organs

The protein content of skeletal muscles is ............ %.

  1. 10

  2. 20

  3. 40

  4. 30
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Skeletal muscle represents the majority of muscle tissue. It is the type of muscle, that powers movement of the skeleton. Their composition is 75-80 percent water, 15-20 percent proteins, 1 percent glycogen, 1 percent lipids and 1 percent mineral salts.

Multiple choice biology our skeletal system and the skin other systems in the body introduction to skeletal system busy at work - our internal organs

Water content of skeletal muscles is ............... %.

  1. 25

  2. 50

  3. 75

  4. 90
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The water and electrolyte content of skeletal muscle was an average of 78.8 gm. of water, 4.96 milliequivalent (meq.) of sodium, 8.32 meq. of potassium, 4.04 meq. of chloride, 0.445 meq. of magnesium, and 3.88 meq. of phosphorus per 100 gm. of wet tissue or muscle. Hence, the percentage of water content in skeletal muscle can vary from 75-78%.

Multiple choice zoology movement and locomotion in man structure of skeletal muscle muscles and their structure skeletal muscles

Which of the following is multinucleated?

  1. Nervous tissue

  2. Striated muscle

  3. Non-striated muscle

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Multinucleate cells are those cells which have more than one nucleus per cell. Skeletal muscles or striated muscles are multinucleated cells. However, smooth muscles or non-striated muscles and cardiac muscles are mononucleated.  
Thus, the correct answer is 'Striated muscle.'

Multiple choice zoology movement and locomotion in man structure of skeletal muscle muscles and their structure skeletal muscles

On stimulation of skeletal muscle, calcium is immediately made available for binding to troponin from

  1. Blood

  2. Lymph

  3. Bone

  4. Sarcoplasmic reticulum
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • A neural signal reaching this junction releases a neurotransmitter (Acetylcholine) which generates an action potential in the sarcolemma. This spreads through the muscle fibre and causes the release of calcium ions into the sarcoplasm from the sarcoplasmic reticulum.
  • Active sites for myosin are present on actin which are masked by troponin-C in resting state. When Ca++ level increases it leads to the binding of calcium with a subunit of troponin i.e Troponin-C on actin(thin) filaments and thereby remove the masking of active sites for myosin.
  • Hence on stimulation of skeletal muscle, calcium is immediately made available for binding to troponin from sarcoplasmic reticulum.
  • So, the correct answer is 'Sacroplasmic reticulum'.
Multiple choice zoology movement and locomotion in man structure of skeletal muscle muscles and their structure skeletal muscles

Read the following statements carefully and select the correct ones. 


(i) Cardiac fibres are branched with one or more nuclei.
(ii) Smooth muscles are unbranched and cylindrical. 
(iii) Skeletal muscles can be branched or unbranched.
(iv) Smooth muscles are non-striated.

  1. Only (iv)

  2. (ii) and (iii)

  3. (iii) and (iv)

  4. Only (iii)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Smooth muscles are indeed non-striated, while the other statements contain inaccuracies (e.g., cardiac fibers are branched but typically have a single nucleus, and skeletal muscles are always striated).

Multiple choice zoology movement and locomotion in man structure of skeletal muscle muscles and their structure skeletal muscles

The cytoplasm in the muscle fibre is called as

  1. Sarcoplasm

  2. Sarcolemma

  3. Neuroplasm

  4. Nucleoplasm
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The cytoplasm in the muscle fibre is called as sarcoplasm. Sarcolemma is the sheath or cell membrane present around the striated muscle fibre. The cytoplasm in the nerve cells is called as neuroplasm. The cytoplasm in the nucleus of the cell is called as necleoplasm. 

Thus, the correct answer is 'Sarcoplasm.'

Multiple choice zoology movement and locomotion in man structure of skeletal muscle muscles and their structure skeletal muscles

All or none law is not applicable for?

  1. Single skeletal muscle fibre

  2. Single smooth muscle fibre

  3. Whole skeletal muscle

  4. Whole cardiac muscle
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The all or none law states that the strength of the stimuli will not decide the reaction of the muscle fibre. f the stimulus is more than a certain threshold they will fire.  Either there will be a full response or there will be no response at all.

As we know that the stimulus works by stimulating the action potential in the fivers. The action potential is always full and thus the response will be there if the threshold is crossed.
We now that the skeletal muscle are the ones that are in control of the conscious mind and the stimuli can affect them so this is applicable for the voluntary muscles.

So, the correct option is 'Single skeletal muscle fibre'

Multiple choice zoology movement and locomotion in man structure of skeletal muscle muscles and their structure skeletal muscles

Striated muscles are found in

  1. Gall bladder

  2. Wall of bronchi

  3. Leg muscles

  4. Lungs
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Striated muscle plays an integral role in the formation of the structural framework of the body. It is the only muscle tissue under the direct conscious control of the cerebral cortex of the brain and hence is the voluntary muscle. All conscious movements of the body, including movement of limbs like the movement of arm, legs, facial expressions, eye movements, and swallowing are the products of the skeletal muscle tissue.
So, the correct answer is option C.
Multiple choice zoology movement and locomotion in man structure of skeletal muscle muscles and their structure skeletal muscles

Find out the correct sequence of muscle structures/components present one within the other 

  1. Muscle fibre $\longrightarrow $ Myofilament $\longrightarrow $ Muscle bundle $\longrightarrow $ Myofibril
  2. Muscle bundle $\longrightarrow $ Muscle fibre$\longrightarrow $ Myofibril $\longrightarrow $ Myofilament
  3. Muscle bundle $\longrightarrow $ Muscle fibre $\longrightarrow $ Myofilament $\longrightarrow $ Myofibril
  4. Muscle fibre $\longrightarrow $ Muscle bundle $\longrightarrow $ Myofilament $\longrightarrow $ Myofibril
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Skeletal muscle is organized hierarchically from largest to smallest: a muscle is made of muscle bundles (fascicles), which contain muscle fibres (cells), which are packed with myofibrils, which in turn consist of myofilaments.

Multiple choice zoology movement and locomotion in man structure of skeletal muscle muscles and their structure skeletal muscles

The protoplasmic segment of a striated muscle fibre is termed as

  1. Sarcoplasm

  2. Sarcomere

  3. Neuromere

  4. Metamere
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sarcomere is the smallest contractile unit of striated muscle fibre. Sarcomere occurs as repeating units along the length of a myofibril, occupying the region between Z lines of the myofibril. 

Sarcoplasm is the cytoplasm of a muscle fibre. It is a water solution containing ATP and phosphogens, as well as the enzymes of intermediate and product molecules involved in many metabolic reactions. 
Neuromere is a metameric segment of CNS. 
Metamere is a linear series of primitively similar segments into which the body of higher invertebrate and vertebrate is divisible.

Multiple choice zoology movement and locomotion in man structure of skeletal muscle muscles and their structure skeletal muscles

Contractile fibrils of muscles are called

  1. Neurofibrils

  2. Callogen fibres

  3. Myofibrils

  4. Yellow fibres
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

  • Each muscle fibre(muscle cell) is lined by the plasma membrane called sarcolemma enclosing the sarcoplasm(cytoplasm of muscle fibre). 
  • The characteristic feature of the muscle fibre(muscle cell) is the presence of a large number of parallelly arranged filaments in the sarcoplasm called myofilaments or myofibrils.
  • Each myofibril is made up of two kinds of proteins. They are actin and myosin.
  • The function of the myofibril is to perform muscle contraction via the sliding-filament model. Hence Contractile fibrils of muscles are called myofibrils.
  • So, the correct answer is 'Myofibrils'.

Multiple choice zoology movement and locomotion in man structure of skeletal muscle muscles and their structure skeletal muscles

Sarcomere is the functional unit of contraction in a muscle fibre. Identify the portion of myofibril that constitutes a sarcomere

  1. Portion of myofibril between two successive Z-lines

  2. Portion of myofibril between two successive I-bands

  3. Portion of myofibril between two successive A-bands

  4. Portion of myofibril between two successive M-lines
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • The ‘A’ and ‘I’ bands are arranged alternately throughout the length of the myofibrils. The light bands contain actin(thin filament) and are called I-band or Isotropic band, whereas the dark band called ‘A’ or Anisotropic band contains myosin(thick filament).
  •  In the centre of each ‘I’ band is an elastic fibre called ‘Z’ line which bisects it. The thin filaments are firmly attached to the ‘Z’ line. The portion of the myofibril between two successive ‘Z’ lines is considered as the functional unit of contraction and is called a sarcomere Sarcomere is considered as the functional unit of contraction in a muscle fibre.
  • So, the correct answer is 'Portion of a myofibril between two successive Z-lines'.