1. (a) All mammals (except a few) have seven cervical vertebra. (b) The number of phalanges in each limb of a human is 14. (c) Thin filament of myofibril contains 2 ‘F’ actins and two other proteins, namely troponin and tropomyosin. (d) In a muscle fibre, Ca++ is stored in the sarcoplasmic reticulum. (Read more

    (a) All mammals (except a few) have seven cervical vertebra.
    (b) The number of phalanges in each limb of a human is 14.
    (c) Thin filament of myofibril contains 2 ‘F’ actins and two other proteins, namely troponin and tropomyosin.
    (d) In a muscle fibre, Ca++ is stored in the sarcoplasmic reticulum.
    (e) 11th and 12th pairs of ribs are called floating ribs.
    (f) The human cranium is made up of eight bones.

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  2. (a) All mammals (except a few) have seven cervical vertebra. (b) The number of phalanges in each limb of a human is 14. (c) Thin filament of myofibril contains 2 ‘F’ actins and two other proteins, namely troponin and tropomyosin. (d) In a muscle fibre, Ca++ is stored in the sarcoplasmic reticulum. (Read more

    (a) All mammals (except a few) have seven cervical vertebra.
    (b) The number of phalanges in each limb of a human is 14.
    (c) Thin filament of myofibril contains 2 ‘F’ actins and two other proteins, namely troponin and tropomyosin.
    (d) In a muscle fibre, Ca++ is stored in the sarcoplasmic reticulum.
    (e) 11th and 12th pairs of ribs are called floating ribs.
    (f) The human cranium is made up of eight bones.

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  3. Skeletal muscle:- 1. The cells of skeletal muscles are unbranched. 2. Intercalated disks are absent. 3. Alternate light and dark bands are present. 4. They are voluntary muscles. 5. They contract rapidly and get fatigued in a short span of time. 6. They are present in body parts such as the legs, toRead more

    Skeletal muscle:-
    1. The cells of skeletal muscles are unbranched.
    2. Intercalated disks are absent.
    3. Alternate light and dark bands are present.
    4. They are voluntary muscles.
    5. They contract rapidly and get fatigued in a short span of time.
    6. They are present in body parts such as the legs, tongue, hands, etc.

    Cardiac muscle:-
    1. The cells of cardiac muscles are branched.
    2. The cells are joined with one another by intercalated disks that help in coordination or synchronization of the heartbeat.
    3. Faint bands are present.
    4. They are involuntary muscles.
    5. They contract rapidly but do not get fatigued easily.
    6. These muscles are present in the heart and control the contraction and relaxation of the heart.

    For more answers visit to website:
    https://www.tiwariacademy.com/ncert-solutions/class-11/biology/chapter-20/

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  4. Movement is a characteristic feature of living organisms. The different types of movement exhibited by cells of the human body are: 1. Amoeboid movement: Leucocytes present in the blood show amoeboid movement. During tissue damage, these blood cells move from the circulatory system towards the injurRead more

    Movement is a characteristic feature of living organisms. The different types of movement exhibited by cells of the human body are:
    1. Amoeboid movement: Leucocytes present in the blood show amoeboid movement. During tissue damage, these blood cells move from the circulatory system towards the injury site to initiate an immune response.
    2. Ciliary movement: Reproductive cells such as sperms and ova show ciliary movement. The passage of ova through the fallopian tube towards the uterus is facilitated by this movement.
    3. Muscular movement: Muscle cells show muscular movement.

    For more answers visit to website:
    https://www.tiwariacademy.com/ncert-solutions/class-11/biology/chapter-20/

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  5. (a) Actin and Myosin:- Actin:- 1 Actin is a thin contractile protein. 2. It is present in light bands and is called an isotropic band. Myosin:- 1. Myosin is a thick contractile protein. 2. It is present in dark bands and is called an anisotropic band. (b) Red and White muscles:- Red muscle fibre:- 1Read more

    (a) Actin and Myosin:-
    Actin:-
    1 Actin is a thin contractile protein.
    2. It is present in light bands and is called an isotropic band.
    Myosin:-
    1. Myosin is a thick contractile protein.
    2. It is present in dark bands and is called an anisotropic band.

    (b) Red and White muscles:-
    Red muscle fibre:-
    1. Red muscle fibres are thin and smaller in size.
    2. They are red in colour as they contain large amounts of myoglobin.
    3. They contain numerous mitochondria.
    4. They carry out slow and sustained contractions for a long period.
    5. They provide energy by aerobic respiration.
    White muscle fibre:-
    1. White muscle fibres are thick and larger in size.
    2. They are white in colour as they contain small amounts of myoglobin
    3. They contain less number of mitochondria.
    4. They carry out fast work for short duration.
    5. They provide energy by anaerobic respiration.

    (c) Pectoral and Pelvic girdle:-
    Pectoral girdle:-
    1. It is a skeletal support from where the forelimbs of vertebrates are attached.
    2. It is composed of two Bones namely, clavicle or collar bones and scapula or shoulder bone.
    Pelvic girdle:-
    1. It is a skeletal support form where the hind limbs of vertebrates are attached.
    2. It is composed of three bones, upper ileum, inner pubic, and ischium.

    For more answers visit to website:
    https://www.tiwariacademy.com/ncert-solutions/class-11/biology/chapter-20/

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