Tag: bones and movements
Questions Related to bones and movements
Upon stimulation of skeletal muscles, calcium is immediately made available for binding to troponin from :
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Blood
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Lymph
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Sacroplasmic reticulum
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Bone
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.
An iron-containing protein myoglobin is present in the
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Spleen
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Lungs
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Muscles
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None of the above
What would be the result of an allele that codes for all actin molecules to be synthesized in linear chains?
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Immovable muscles
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Smooth muscle tissue
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Normal sarcomere structure
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Degeneration of muscle tissue
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Muscle tendons that cannot attach
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.
Which of the following is the result of synthesis of actin molecule(coded by allele) in a linear chain?
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Immovable muscles
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Smooth muscle tissue
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Normal sarcomere structure
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Degeneration of muscle tissue
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Muscle tendons that cannot attach
- 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.
The binding of troponin to calcium in muscle cells exposes the binding site of
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Tropomyosin
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Myosin
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ATP
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ADP
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${P} _{i}$
- 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.
${Ca}^{2+}$ and ${Mg}^{2+}$ ions
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Reduce excitability of nerves and muscles.
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Increase excitability of nerves and muscles.
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Conduct nerve impulses.
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Both B and C.
ATP-ase needed for muscle contraction is present over
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Aetinin
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Troponin
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Myosin
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Actin
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'.
Which of these ions are involved in muscle contraction?
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$Ca^{2+}$ and $Mg^{2+}$
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$Ca^{2+}$ and $Na^+$
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$Na^+$ and $K^+$
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$Mg^{2+}$ and $K^+$
- 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$^{2+}$'.
The cartilage making up the lower jaw is known a
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Dentary
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Metapophysis
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Anapophysis
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Post-zygapophysis
Lower jaw or II part of mandibular arch is cartilage nous initially and is called nickel's cartilage, which soon changes into bony structure.
The immediate regeneration of ATP used up during muscle
contraction is facilitated by
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Glucose
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Glycogen
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Lactic acid
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Creatine phosphate
The excess ATP is used to synthesize creatine Phosphate, an energy rich molecule that is found in muscle fibres.