Class 10 Science

Life Processes NCERT Eemplar Problems

MCQ Part 2

Question 12: The correct sequence of anaerobic reactions in yeast is

  1. Glucose (In cytoplasm) → Pyruvate (In mitochondria) → Ethanol + Carbondioxide
  2. Glucose (In cytoplasm) → Pyruvate (In cytoplasm) → Lactic acid
  3. Glucose (In cytoplasm) → Pyruvate (In mitochondria) → Lactic acid
  4. Glucose (In cytoplasm) → Pyruvate (In cytoplasm) → Ethanol + Carbondioxide

Answer: (d) Glucose (In cytoplasm) → Pyruvate (In cytoplasm) → Ethanol + Carbondioxide

Question 13: Which of the following is most appropriate for aerobic respiration?

  1. Glucose (in mitochondria) → Pyruvate (in cytoplasm) → CO2 + H2O + Energy
  2. Glucose (in cytoplasm) → Pyruvate (in mitochondria) → CO2 + H2O + Energy
  3. Glucose (in cytoplasm) → Pyruvate + Energy(in mitochondria) → CO2 + H2O
  4. Glucose (in cytoplasm) → Pyruvate + Energy(in mitochondria) → CO2 + H2O + Energy

    Answer: (b) Glucose (in cytoplasm) → Pyruvate (in mitochondria) → CO2 + H2O + Energy

Question 14: Which of the following statement(s) is (are) true about respiration?

  1. During inhalation, ribs move inward and diaphragm is raised
  2. 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
  3. Haemoglobin has greater affinity for carbon dioxide than oxygen
  4. Alveoli increase surface area for exchange of gases
  1. (1) and (4)
  2. (2) and (3)
  3. (1) and (3)
  4. (2) and (4)

    Answer: (d) (2) and (4)

Question 15: Which is the correct sequence of air passage during inhalation?

  1. Nostrils → larynx → pharynx → trachea → lungs
  2. Nasal passage → trachea → pharynx → larynx → alveoli
  3. Larynx → nostrils → pharynx → lungs
  4. Nostrils → pharynx → larynx → trachea → alveoli

    Answer: a) Nostrils → larynx → pharynx → trachea → lungs

Question 16: During respiration exchange of gases take place in

  1. Trachea and larynx
  2. Alveoli of lungs
  3. Alveoli and throat
  4. Throat and larynx

    Answer: (b) Alveoli of lungs

Question 17: Which of the following statement (s) is (are) true about heart?

  1. Left atrium receives oxygenated blood from different parts of body while right atrium receives deoxygenated blood from lungs
  2. Left ventricle pumps oxygenated blood to different body parts while right ventricle pumps deoxygenated blood to lungs
  3. Left atrium transfers oxygenated blood to right ventricle which sends it to different body parts
  4. Right atrium receives deoxygenated blood from different parts of the body while left ventricle pumps oxygenated blood to different parts of the body.
  1. (1)
  2. (2)
  3. (2) and (4)
  4. (1) and(3)

    Answer: (c) (2) and (4)

Explanation: Deoxygenated blood flows through the right side of the heart. Oxygenated blood flows through the left side of the heart.

Question 18: What prevents backflow of blood inside the heart during contraction?

  1. Valves in heart
  2. Thick muscular walls of ventricles
  3. Thin walls of atria
  4. All of the above

    Answer: (a) Valves in heart

Question 19: Single circulation i.e., blood flows through the heart only once during one cycle of passage through the body, is exhibited by

  1. Labeo, Chameleon, Salamander
  2. Hippocampus, Exocoetus, Anabas
  3. Hyla, Rana, Draco
  4. Whale, Dolphin, Turtle

    Answer: (b) Hippocampus, Exocoetus, Anabas

Explanation: These animals belong to pisces. Single circulation is found in fishes.

Question 20: In which of the following vertebrate group/groups, heart does not pump oxygenated blood to different parts of the body?

  1. Pisces and amphibians
  2. Amphibians and reptiles
  3. Amphibians only
  4. Pisces only

    Answer: (d) Pisces only

Explanation: In fishes, heart sends the blood to gills from where blood is circulated to different organs.

Question 21: Choose the correct statement that describes arteries.

  1. They have thick elastic walls, blood flows under high pressure; collect blood from different organs and bring it back to the heart
  2. They have thin walls with valves inside, blood flows under low pressure and carry blood away from the heart to various organs of the body
  3. They have thick elastic walls, blood flows under low pressure; carry blood from the heart to various organs of the body
  4. They have thick elastic walls without valves inside, blood flows under high pressure and carry blood away from the heart to different parts of the body.

    Answer: (d) They have thick elastic walls without valves inside, blood flows under high pressure and carry blood away from the heart to different parts of the body.

Question 22: The filtration units of kidneys are called

  1. Urethra
  2. Ureter
  3. Neurons
  4. Nephrons

    Answer: (d) Nephrons

Question 23: Oxygen liberated during photosynthesis comes from

  1. Water
  2. Chlorophyll
  3. Carbon dioxide
  4. Glucose

    Answer: (a) Water

Explanation: Energy from sunlight is utilized to split water molecule. Splitting of water molecule gives H+ ion and Oxygen.

Question 24: The blood leaving the tissues becomes richer in

  1. Carbon dioxide
  2. Water
  3. Haemoglobin
  4. Oxygen

    Answer: (a) Carbon dioxide