Tag: muscles

Quizzes (1) Questions (39)

Questions Related to muscles

Multiple choice zoology skeleton - movement and locomotion types of muscles muscles muscles and their structure

Gastrocnemius muscles are found in

  1. Fore arm

  2. Chest

  3. Thigh

  4. Shank
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • The two major types of muscles that make up the calf (back portion of the lower leg) are gastrocnemius and soleus muscle.
  • Along with the soleus muscle, the gastrocnemius forms half of the calf muscle. Its function is plantar flexing the foot at the ankle joint and flexing the leg at the knee joint.
  • Hence gastrocnemius muscles are found in shank(a person's leg, especially the part from the knee to the ankle).
  • So, the correct answer is 'Shank'.
Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

Upon stimulation of skeletal muscles, calcium is immediately made available for binding to troponin from :

  1. Blood

  2. Lymph

  3. Sacroplasmic reticulum

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

Answer is option C i.e. "Sacroplasmic reticulum"
Neurotransmitter acetylcholine generates an action potential in the sarcolemma causing the release of calcium ions into the sarcoplasm from the sarcoplasmic reticulum.
When Ca++ level increases it leads to the binding of calcium with a sub-unit of troponin on actin(thin) filaments and thereby activating the movement.

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

An iron-containing protein myoglobin is present in the

  1. Spleen

  2. Lungs

  3. Muscles

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Myoglobin is the iron and oxygen-binding protein that is found in the muscle tissue of the vertebrates and in almost all mammals. This contains heme, the pigment responsible for the red color of meat.

Therefore, the correct answer is option C.

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

What would be the result of an allele that codes for all actin molecules to be synthesized in linear chains?

  1. Immovable muscles

  2. Smooth muscle tissue

  3. Normal sarcomere structure

  4. Degeneration of muscle tissue

  5. Muscle tendons that cannot attach
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sarcomere is the structural and functional unit of a myofibril and consists of thick myosin filaments and thin actin filaments. If the allele for actin filament continues to synthesize linear chains of the protein, sarcomere structure would be same as normal. Thus, the correct answer is option C.

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

Which of the following is the result of synthesis of actin molecule(coded by allele) in a linear chain?

  1. Immovable muscles

  2. Smooth muscle tissue

  3. Normal sarcomere structure

  4. Degeneration of muscle tissue

  5. Muscle tendons that cannot attach
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • A sarcomere is the functional unit (contractile unit) of a muscle fibre. 
  • Each sarcomere contains two types of myofilaments: thick filaments, composed primarily of the contractile protein myosin, and thin filaments, composed primarily of the contractile protein actin. Hence, Normal sarcomere structure is the result of the synthesis of actin molecule(coded by allele) in a linear chain.
So, the correct answer is 'Normal sarcomere structure'.
 
Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

The binding of troponin to calcium in muscle cells exposes the binding site of

  1. Tropomyosin

  2. Myosin

  3. ATP

  4. ADP
  5. ${P} _{i}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

  • Muscle contraction thus results from an interaction between the actin and myosin filaments that generates their movement relative to one another. 
  • The molecular basis for this interaction is the binding of myosin to actin filaments, allowing myosin to function as a motor that drives filament sliding. Hence, The binding of troponin to calcium in muscle cells exposes the binding site of Myosin.
So, the correct answer is 'Myosin'.

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

${Ca}^{2+}$ and ${Mg}^{2+}$ ions 

  1. Reduce excitability of nerves and muscles.

  2. Increase excitability of nerves and muscles.

  3. Conduct nerve impulses.

  4. Both B and C.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

High calcium and magnesium ion concentration decrease the excitability of the muscle fiber membrane by raising the threshold to stimulation, while a low level of the calcium and magnesium ions increase the excitability of muscles fibers. 
So, the correct answer is A.
Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

ATP-ase needed for muscle contraction is present over

  1. Aetinin

  2. Troponin

  3. Myosin

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

ATPase needed for muscle contraction is present over the myosin. Myosin binds to actin at a binding site. Myosin has another binding site for ATP at which enzymatic activity of myosin ATPase hydrolyzes ATP to ADP which releases an inorganic phosphate molecule and energy. The energy released during ATP hydrolysis changes the angle of the myosin head into a cocked position. The myosin head is then in a position for further movement possessing potential energy. The enzyme myosin ATPase catalyses the reaction in the presence of Ca$^{2+}$ and Mg$^{2+}$. So, the correct answer is 'Myosin'.

Multiple choice biology locomotion and movement locomotion in animals bones and movements muscle contraction types of muscles muscles

Which of these ions are involved in muscle contraction? 

  1. $Ca^{2+}$ and $Mg^{2+}$
  2. $Ca^{2+}$ and $Na^+$
  3. $Na^+$ and $K^+$
  4. $Mg^{2+}$ and $K^+$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Active sites for myosin(Thick filament) are present on actin which are masked by troponin in resting state. when  Ca++ level increases it leads to the binding of calcium with a subunit of troponin on actin(thin) filaments and thereby remove the masking of active sites for myosin.
  • Utilizing the energy from ATP hydrolysis, the myosin head now binds to the exposed active sites on actin to form a cross bridge. 
  • This pulls the attached actin filaments towards the centre of ‘A’ band.
  •  The ‘Z’ line attached to these actins are also pulled inwards thereby causing a shortening of the sarcomere, i.e., contraction.
  • Magnesium also plays a role in regulating muscle contractions. Magnesium acts as a natural calcium blocker to help muscles relax. Hence Ca++ and Mg++ ions are involved in muscle contractions.
  • So, the correct answer is 'Ca$^{2+}$ and Mg$^{2+}$'.