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NCERT Exemplar · Class 10 Science Life Processes

82 questions · 82 still being checked

Multiple Choice Questions 11–20 (part 2 of 9)

  1. Exercise 11

    When air is blown from mouth into a test-tube containing lime water, the lime water turned milky due to the presence of
    (a)
    oxygen
    (b)
    carbon dioxide
    (c)
    nitrogen
    (d)
    water vapour

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    (b)
    (b) Carbon dioxide. \[\mathrm{Ca(OH)_2 + CO_2 \rightarrow CaCO_3\downarrow + H_2O} \] Exhaled breath is rich in \(\displaystyle \mathrm{CO_2}\), which reacts with lime water to give insoluble calcium carbonate, turning it milky.

  2. Exercise 12

    The correct sequence of anaerobic reactions in yeast is
    (a)
    Glucose →cytoplasm\displaystyle \xrightarrow{\text{cytoplasm}} Pyruvate →mitochondria\displaystyle \xrightarrow{\text{mitochondria}} Ethanol + Carbondioxide
    (b)
    Glucose →cytoplasm\displaystyle \xrightarrow{\text{cytoplasm}} Pyruvate →cytoplasm\displaystyle \xrightarrow{\text{cytoplasm}} Lactic acid
    (c)
    Glucose →cytoplasm\displaystyle \xrightarrow{\text{cytoplasm}} Pyruvate →mitochondria\displaystyle \xrightarrow{\text{mitochondria}} Lactic acid
    (d)
    Glucose →cytoplasm\displaystyle \xrightarrow{\text{cytoplasm}} Pyruvate →cytoplasm\displaystyle \xrightarrow{\text{cytoplasm}} Ethanol + Carbondioxide

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    (d)
    (d) Ethanol and carbon dioxide, both formed in the cytoplasm. Yeast has no aerobic route here — glycolysis and the fermentation step both stay in the cytoplasm, unlike muscle cells, which instead accumulate lactic acid.

  3. Exercise 13

    Which of the following is most appropriate for aerobic respiration?
    (a)
    Glucose →mitochondria\displaystyle \xrightarrow{\text{mitochondria}} Pyruvate →cytoplasm\displaystyle \xrightarrow{\text{cytoplasm}} CO2+H2O+\displaystyle \mathrm{CO}_2+\mathrm{H}_2\mathrm{O}+ Energy
    (b)
    Glucose →cytoplasm\displaystyle \xrightarrow{\text{cytoplasm}} Pyruvate →mitochondria\displaystyle \xrightarrow{\text{mitochondria}} CO2+H2O+\displaystyle \mathrm{CO}_2+\mathrm{H}_2\mathrm{O}+ Energy
    (c)
    Glucose →cytoplasm\displaystyle \xrightarrow{\text{cytoplasm}} Pyruvate + Energy →mitochondria\displaystyle \xrightarrow{\text{mitochondria}} CO2+H2O\displaystyle \mathrm{CO}_2+\mathrm{H}_2\mathrm{O}
    (d)
    Glucose →cytoplasm\displaystyle \xrightarrow{\text{cytoplasm}} Pyruvate + Energy →mitochondria\displaystyle \xrightarrow{\text{mitochondria}} CO2+H2O+\displaystyle \mathrm{CO}_2+\mathrm{H}_2\mathrm{O}+ Energy

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    (d)
    (d) \[\mathrm{Glucose} \xrightarrow{\text{cytoplasm}} \mathrm{Pyruvate} + \text{Energy} \] \[\mathrm{Pyruvate} \xrightarrow{\text{mitochondria}} \mathrm{CO_2} + \mathrm{H_2O} + \text{Energy} \] Energy is released at both stages: glycolysis yields a little ATP, complete oxidation yields most of it.

  4. Exercise 14

    Which of the following statement(s) is (are) true about respiration?
    (i)
    During inhalation, ribs move inward and diaphragm is raised
    (ii)
    In the alveoli, exchange of gases takes place i.e., oxygen from alveolar air diffuses into blood and carbon dioxide from blood into alveolar air
    (iii)
    Haemoglobin has greater affinity for carbon dioxide than oxygen
    (iv)
    Alveoli increase surface area for exchange of gases
    (a) (i) and (iv)
    (b) (ii) and (iii)
    (c) (i) and (iii)
    (d) (ii) and (iv)

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    (d)
    (d) (ii) and (iv). Gas exchange at the alveoli and their large surface area are correctly stated; inhalation instead pulls the ribs outward and flattens (lowers) the diaphragm, and haemoglobin's affinity is for oxygen, not \(\displaystyle \mathrm{CO_2}\).

  5. Exercise 15

    Which is the correct sequence of air passage during inhalation?
    (a)
    Nostrils → larynx → pharynx → trachea → lungs
    (b)
    Nasal passage → trachea → pharynx → larynx → alveoli
    (c)
    larynx → nostrils → pharynx → lungs
    (d)
    Nostrils → pharynx → larynx → trachea → alveoli

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    (d)
    (d) Nostrils → pharynx → larynx → trachea → alveoli. Air is warmed and filtered in the nasal passage, crosses the voice box (larynx), then travels down the trachea into narrowing bronchi ending at alveoli.

  6. Exercise 16

    During respiration exchange of gases take place in
    (a)
    trachea and larynx
    (b)
    alveoli of lungs
    (c)
    alveoli and throat
    (d)
    throat and larynx

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    (b)
    (b) Alveoli of lungs. Alveoli are thin-walled, single-cell-thick sacs richly wrapped in capillaries, giving a large surface area where \(\displaystyle \mathrm{O_2}\) diffuses into blood and \(\displaystyle \mathrm{CO_2}\) diffuses out.

  7. Exercise 17

    Which of the following statement (s) is (are) true about heart?
    (i)
    Left atrium receives oxygenated blood from different parts of body while right atrium receives deoxygenated blood from lungs
    (ii)
    Left ventricle pumps oxygenated blood to different body parts while right ventricle pumps deoxygenated blood to lungs
    (iii)
    Left atrium transfers oxygenated blood to right ventricle which sends it to different body parts
    (iv)
    Right atrium receives deoxygenated blood from different parts of the body while left ventricle pumps oxygenated blood to different parts of the body
    (a)(i)
    (b)(ii)
    (c) (ii) and (iv)
    (d) (i) and (iii)

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    (c)
    (c) (ii) and (iv). Right atrium receives deoxygenated blood from the body; left ventricle pumps oxygenated blood to the body. Statements (i) and (iii) confuse the left and right sides of the heart.

  8. Exercise 18

    What prevents backflow of blood inside the heart during contraction?
    (a)
    Valves in heart
    (b)
    Thick muscular walls of ventricles
    (c)
    Thin walls of atria
    (d)
    All of the above

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    (a)
    (a) Valves in heart. Each valve opens one way only, so blood cannot flow back into the atria, or from the arteries into the ventricles.

  9. Exercise 19

    Single circulation i.e., blood flows through the heart only once during one cycle of passage through the body, is exhibited by
    (a)
    Labeo, Chameleon, Salamander
    (b)
    Hippocampus, Exocoetus, Anabas
    (c)
    Hyla, Rana, Draco
    (d)
    Whale, Dolphin, Turtle

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    (b)
    (b) Hippocampus, Exocoetus, Anabas. All three are fishes with a two-chambered heart; blood passes through the heart once per cycle before reaching the gills and then the body. Option (a) mixes classes with different circulation.

  10. Exercise 20

    In which of the following vertebrate group/groups, heart does not pump oxygenated blood to different parts of the body?
    (a)
    Pisces and amphibians
    (b)
    Amphibians and reptiles
    (c)
    Amphibians only
    (d)
    Pisces only

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    (d)
    (d) Pisces only. A fish's two-chambered heart pumps only deoxygenated blood, to the gills; an amphibian's single ventricle pumps mixed, partly oxygenated blood to the body.