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CBSE Questions for Class 11 Medical Biology Locomotion And Movement Quiz 5 - MCQExams.com
CBSE
Class 11 Medical Biology
Locomotion And Movement
Quiz 5
The filaments of myofibril are made up of
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Actin, troponin, tropomyosin
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Actin, troponin
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Myosin, troponin
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Actin, tropomyosin
Explanation
Myofibrils are the contractile fibres that are present in the striated muscles and are also called as the muscle fibres. They are composed of the thick and thin filaments called the actin and myosin along with the troponin and tropomyosin muscle proteins.
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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$${P}_{i}$$
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'.
Label the correct parts of the Myosin monomer :
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A. Cross arm
B. Actin binding site
C. Head
D. ATP binding site
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A. Head
B. Cross arm
C. Actin binding site
D. ATP binding site
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A. Actin binding site
B. Head
C. ATP binding site
D. Cross arm
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A. ATP binding site
B. Actin binding site
C. Head
D. Cross arm
Explanation
Each actin (thin) filament is made of two filamentous actins helically wound to each other. Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins.
There are two important parts, a globular head
(here, labelled as A)
with a short arm and a tail, the former being called the heavy meromyosin (HMM) and the latter, the light meromyosin (LMM).
The HMM component, i.e., the head and short arm projects outwards at a regular distance and angle from each other from the surface of a polymerised myosin filament and are known as the cross arm (here, labelled as B).
The globular head is an active ATPase enzyme and has binding sites for ATP
(here, labelled as D)
and active sites for actin
(here, labelled as C).
Thus, the correct answer is option B.
Which of the following would ensure healthy joints?
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Playing outdoor games
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Playing indoor games
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Eating more red meat
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Use of massage oil
Explanation
Walking and playing in fresh air keeps the body fit and healthy. One must also have a balanced diet and maintain a healthy body weight.
Myosin filaments are localized in
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Z-Band
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H-Band
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A-Band
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None of the above
Explanation
Each myofibril (muscle filament)has alternate dark and light bands on it.
The light bands contain actin and are called I-band or Isotropic band, whereas the dark band called ‘A’ or Anisotropic band contains Myosin.
Myosin filaments are also called as Thick filaments.
Hence Myosin filaments are localized in A-Band.
So, the correct answer is 'A-Band'.
Deposition of ______ in the joints causes gout.
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Urea
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Uric acid
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Guanine
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Ammonia
Explanation
Gout is a disorder in which deposits of uric acid crystals accumulate in the joints because of high levels of uric acid in the blood (hyperuricemia). The accumulations of crystals cause flare-ups (attacks) of painful inflammation in and around joints.
Hence, the correct answer is option B.
Cardiac muscles are resistant to fatigue.
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True
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False
Explanation
Normal muscles like the skeletal muscles get fatigued (
strenuous activities like exercise, sports etc.) due
to the formation of lactic acid as a result of anaerobic glycolysis. But cardiac muscles do not form lactic acid due to the presence of rich capillary network which provides enough oxygen to the muscles. Anaerobic processes never occur in cardiac muscles, hence lactic acid is never formed enabling heart muscles to perform their function without fatigue.
Therefore, the statement that cardiac muscles are fatigue resistant is true.
Major protein in the thick filaments of skeletal muscle fiber is
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Myosin
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Actin
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Tropomyosin
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Troponin
Explanation
Skeletal muscle fiber is made up of two types of filaments. They are thick filament and thin filament.
Thick filament is made up of a protein called Myosin.
Each myosin (thick filament) is made up of Many monomeric proteins called Meromyosins.
Hence Major protein in the thick filaments of skeletal muscle fiber is Myosin.
So, the correct answer is 'Myosin'.
Which of the following is the property of cardiac muscle?
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It is involuntary muscles.
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It is resistant to fatigue.
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It is striated muscle.
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All of the above.
Explanation
Cardiac muscle is a specialized tissue that is found only in the heart.
Their contraction can't be controlled thus they are involuntary in nature.
As the function of cardiac muscles is to continuously and repeatedly contract and relax, they are needed to be striated.
The arrangement of myofibrils due to which the light and dark bands appear.
Cardiac muscles are primarily powered by mitochondria (the energy house of the cell), similar to your other muscles. However, cardiac muscles have as much as 10 times the density of mitochondria, thus they cannot get fatigued.
So, the correct answer is 'all the above'.
At times ligaments and tendons are overstretched or torn. The phenomenon is
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Sprain
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Dislocation
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Fracture
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Tension
Explanation
The bands of fibrous tissue that connect bones to bones at joints are called as Ligaments and which connect muscles to the bones are called as tendons.
At times ligaments and tendons are overstretched or torn. The phenomenon is called a sprain.
Sprain happen most often in the ankle but can occur at any joint, such as the wrist or knee.”
So, the correct answer is a 'Sprain'.
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 $$K^+$$
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$$^{2+}$$'.
$${Ca}^{2+}$$ 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.
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.
Identify the joints, which are freely movable.
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Fibrous joints
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Symphyses
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Synovial joints
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Cartilaginous joints
Explanation
A synovial joint is a connection between two bones consisting of a cartilage lined cavity filled with fluid. Synovial joints are capable of the greatest movement. Knees, elbows and shoulders are examples of synovial joints. Since they allow for free movement, synovial joints are classified as diarthrosis. They allow for many types of movement including gliding, angular, rotational etc. So, the correct answer is 'Synovial joints'.
Gastrocnemius muscles are found in
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Fore arm
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Chest
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Thigh
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Shank
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'.
Major protein in thick filaments of skeletal muscle fibre is?
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Myosin
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Actin
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Tropomyosin
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Troponin
Explanation
The main contractile components of a muscle fibre include:
Thick filaments - The major protein of a thick filament is myosin.
Thin filaments - The major proteins of a thin filament include actin, as well as troponin and tropomyosin. Hence, Major protein in thick filaments of skeletal muscle fibre is myosin.
So, the correct answer is 'myosin'.
In skeleton muscle Z-line is connected to.
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Actin
0%
Myosin
0%
Tropomyosin
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Hensen's line
Explanation
Each myofibril consists of a series of contractile units (sarcomeres) connected at a protein border (the Z line).
Thin filaments(actin) of adjacent sarcomeres are present in the Z line between the thin filaments are thick filaments(myosin).
The protein tropomyosin winds around the thin filaments and covers the myosin binding sites. Hence, In skeleton muscle, Z-line is connected to actin.
So, the correct answer is 'actin'.
Component of actin filament of a sarcomere is
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Myosin and troponin
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Troponin and actin
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Actin and myosin
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Actin, troponin and tropomyosin
Explanation
Skeletal muscle fiber is made up of two types of filaments. They are thick filament(myosin) and thin filament(actin).
Each actin (thin) filament is made of two ‘F’ (filamentous) actins helically wound to each other. Two filaments of another protein, tropomyosin also run close to the ‘F’ actins throughout its length. A complex protein Troponin is distributed at regular intervals on the tropomyosin.
Hence Component of actin filament of a sarcomere is Actin, troponin, and tropomyosin.
So, the correct answer is 'Actin, troponin, and tropomyosin'.
Sprain is due to outstretching/pulling of
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Muscles
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Tendons
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Ligaments
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Nerves
Explanation
A sprain is a stretching or tearing of ligaments which are the tough bands of fibrous tissue that connect two bones together in the joints. A sprain results in an overstretch or tear of the ligaments supporting that joint.
So, the correct answer is 'ligaments'.
A joint made for power is
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Knee joint
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Suture in cranium
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Joint between vertebrae
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Mandibular joint
Explanation
The lower jaw is made up of a single bone called mandible.
The mandible is the longest and strongest bone in the face. It forms the lower jaw and holds the teeth in place.
Movement of the lower jaw opens and closes the mouth and also allows for the chewing of food. The lower set of teeth in the mouth is rooted in the lower jaw.
The mandibular joint is a joint made for power. It connects the lower jaw bone to the skull.
So, the correct answer is 'Mandibular joint'.
Identify the thick myofilament from the given contractile proteins.
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Troponin
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Myosin
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Tropomyosin
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Actin
Explanation
Skeletal muscle fiber is made up of two types of filaments. They are thick filament and thin filament.
Thick filament is made up of a protein called Myosin.
Actin filaments are thinner as compared to the myosin filaments, hence are commonly called thin and thick filaments respectively
Each myosin (thick filament) is made up of Many monomeric proteins called Meromyosins.
Hence the thick myofilament from the given contractile proteins is myosin.
So.the correct answer is 'Myosin'.
Which one among the following is a cartilaginous joint?
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Synchondrosis
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Symphysis
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Diarthrosis
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Both A and B
Explanation
Cartilaginous joints are connected entirely by cartilage and allow more movement between bones. There are two types of cartilaginous joints which are synchondroses and symphyses. Diarthrosis is a type of synovial joint. So, the correct answer is 'Both A and B'.
The functional unit of contractile system of a striated muscle is:
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Sarcomere
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Z-band
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Cross bridge
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Myofibril
Explanation
Each myofibril(a unit of the muscle cell) has alternate dark and light bands on it.
The light bands contain actin and are called I-band or Isotropic band, whereas the dark band called ‘A’ or Anisotropic band contains myosin.
In the center 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 ‘A’ and ‘I’ bands are arranged alternately throughout the length of the myofibrils.
The sarcomere is considered as the functional unit of contraction. The portion of the myofibril between two successive ‘Z’ lines is considered as a sarcomere. Hence The functional unit of the contractile system of a striated muscle is sarcomere.
So, the correct answer is 'Sarcomere'.
Globular protein which masks active sites on F-actin is
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Troponin
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Tropomyosin
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Myosin
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Light meromyosin
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Heavy meromyosin
Explanation
Troponin is a globular protein which is attached to the protein tropomyosin which lies on actin filaments in muscle tissue in the relaxed muscle. This blocks the attachment site for the myosin cross-bridge, thus preventing contraction. When the muscle cell is stimulated to contract, the calcium ions attaches to troponin, which causes it to change shape, exposing binding sites for myosin on the actin filaments. Myosin's binding to actin causes cross-bridge formation and contraction of the muscle begins. So, the correct answer is 'Troponin'.
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
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'.
Joints of skull bones are
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Synarthrosis
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Amiphiarthrosis
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Hemarthrosis
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Diarthrosis
Explanation
A synarthrosis is a fixed joint between bones connected by fibrous tissue. A suture is a type of fibrous joint that is only found in the skull. The sutures between bones of the skull is an example of synarthrosis. So, the correct answer is 'Synarthrosis'.
Sutural joints are present between
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Thumb and metatarsal
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Humerus and radius-ulna
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Parietals of skull
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Glenoid cavity and pectoral girdle
Explanation
Joints are points of contact between bones, or between bones and cartilages.
A suture is a type of fibrous joint that is only found in the skull. Parietals are the bones present in the skull.
Sutural joints are present between parietals (bones of the skull)of the skull.
So, the correct answer is 'Parietals of the skull'.
Select the correct statement about disorder of muscular or skeletal system.
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Muscular dystrophy
$$\rightarrow$$
Age related shortening of muscles
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Myasthenia gravis
$$\rightarrow$$
Autoimmune disorder which inhibits sliding of myosin filaments
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Gout
$$\rightarrow$$
Inflammation of joints due to extra deposition of calcium
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Osteoporosis
$$\rightarrow$$
Decrease in bone mass and higher chances of fractures with advancing age
Explanation
Skeletal system consists of a framework of bones and a few cartilages.
Osteoporosis is defined as a low bone mass and microarchitectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk.
It occurs due to various fractures such as calcium deficiency, hyperparathyroidism, estrogen deficiency in females etc,
Hence osteoporosis →→ Decrease in bone mass and higher chances of fractures with advancing age.
So, the correct answer is 'Osteoporosis →→ Decrease in bone mass and higher chances of fractures with advancing age'.
Which is wrongly matched?
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Red muscle-myoglobin
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Tendon-connective tissue
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Troponin-fibrous protein
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Smooth muscle-involuntary muscle
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Myosin-contractile protein
Explanation
The myofibril is composed of two types of filaments. They are thick filament(Myosin) and Thin filament(Actin).
Each actin (thin) filament is made of two ‘F’ (filamentous) actins helically wound to each other. Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins. Two filaments of another protein, tropomyosin also run close to the ‘F’ actins throughout its length. A complex protein Troponin is distributed at regular intervals on the tropomyosin. In the resting state tropomyosin partially covers myosin binding site on actin. Tropomyosin is a fibrous protein and Troponin is a globular protein.
So, the correct answer is '
Troponin-fibrous protein'
Symphysis consists of
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Hyaline cartilage
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Elastic cartilage
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Fibrocartilage
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Synovial fluid
Explanation
A symphysis is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint. They allow more movement between bones than a fibrous joint but less than the highly mobile synovial joint.
So, the correct answer is 'Fibrocartilage'.
Bones become fragile due to
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0%
Arthritis
0%
Osteoporosis
0%
Gout
0%
Myasthenia gravis
Explanation
Osteoporosis is defined as low bone mass and microarchitectural deterioration of the bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk.
It may occur due to various reasons such as calcium deficiency, increase in osteoclastic or osteoblastic activity, age, estrogen deficiency in females etc.
Hence, bones become fragile (easily broken or damaged) due to osteoporosis.
So, the correct answer is 'Osteoporosis'.
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