Photosynthesis, Respiration, Digestion and Circulation

Attempt the quiz above first, then review every question with its correct answer and a short explanation below.

1. Q1.Which gas is released during photosynthesis?

   • A.oxygen✓ Correct Answer
   • B.carbon dioxide
   • C.nitrogen
   • D.hydrogen

   Explanation: Water is split and oxygen is released.

2. Q2.Photosynthesis requires sunlight, water and:

   • A.oxygen
   • B.nitrogen
   • C.carbon dioxide✓ Correct Answer
   • D.ammonia

   Explanation: It enters leaves through stomata.

3. Q3.Cellular respiration mainly releases:

   • A.light
   • B.sound
   • C.energy✓ Correct Answer
   • D.magnetism

   Explanation: The energy is stored as ATP.

4. Q4.The largest gland in the human body is the:

   • A.pancreas
   • B.liver✓ Correct Answer
   • C.thyroid
   • D.pituitary

   Explanation: It also produces bile.

5. Q5.The main organs of excretion in humans are the:

   • A.kidneys✓ Correct Answer
   • B.lungs
   • C.liver only
   • D.stomach

   Explanation: They filter urea from the blood.

6. Q6.Digestion of starch begins in the:

   • A.stomach
   • B.small intestine
   • C.large intestine
   • D.mouth✓ Correct Answer

   Explanation: Salivary amylase acts on starch.

7. Q7.Most of the absorption of digested food takes place in the:

   • A.small intestine✓ Correct Answer
   • B.stomach
   • C.large intestine
   • D.oesophagus

   Explanation: Villi greatly increase the absorbing surface.

8. Q8.The enzyme in saliva that digests starch is:

   • A.pepsin
   • B.salivary amylase✓ Correct Answer
   • C.lipase
   • D.trypsin

   Explanation: It converts starch to maltose.

9. Q9.Pepsin, secreted in the stomach, digests:

   • A.fats
   • B.starch
   • C.vitamins
   • D.proteins✓ Correct Answer

   Explanation: It works in acidic conditions.

10. Q10.Bile, which helps in fat digestion, is stored in the:

    • A.pancreas
    • B.gall bladder✓ Correct Answer
    • C.stomach
    • D.spleen

    Explanation: It is made in the liver.

11. Q11.Loss of water vapour from the aerial parts of plants is called:

    • A.translocation
    • B.respiration
    • C.guttation
    • D.transpiration✓ Correct Answer

    Explanation: It mostly occurs through stomata.

12. Q12.The human heart has how many chambers?

    • A.four✓ Correct Answer
    • B.two
    • C.three
    • D.five

    Explanation: Two atria and two ventricles.

13. Q13.The pigment that carries oxygen in human blood is:

    • A.chlorophyll
    • B.melanin
    • C.carotene
    • D.haemoglobin✓ Correct Answer

    Explanation: It is found in red blood cells.

14. Q14.The universal blood donor group is:

    • A.A
    • B.O✓ Correct Answer
    • C.B
    • D.AB

    Explanation: Group AB is the universal recipient.

15. Q15.Anaerobic respiration in yeast produces:

    • A.lactic acid only
    • B.ethanol and carbon dioxide✓ Correct Answer
    • C.oxygen
    • D.water only

    Explanation: This is the basis of fermentation in bread and brewing.

16. Q16.Red blood cells in adults are produced mainly in the:

    • A.liver
    • B.spleen
    • C.bone marrow✓ Correct Answer
    • D.kidney

    Explanation: Red bone marrow is the site of blood cell formation.

17. Q17.ATP is called the:

    • A.energy currency of the cell✓ Correct Answer
    • B.genetic material
    • C.structural protein
    • D.storage fat

    Explanation: Energy is released when it loses a phosphate group.

18. Q18.Glycolysis takes place in the:

    • A.nucleus
    • B.mitochondrial matrix
    • C.cytoplasm✓ Correct Answer
    • D.chloroplast

    Explanation: It breaks glucose into two pyruvate molecules.

19. Q19.The Krebs cycle takes place in the:

    • A.cytoplasm
    • B.nucleus
    • C.mitochondrial matrix✓ Correct Answer
    • D.ribosome

    Explanation: It is also called the citric acid cycle.

20. Q20.The main nitrogenous waste excreted by humans is:

    • A.uric acid
    • B.ammonia
    • C.creatinine only
    • D.urea✓ Correct Answer

    Explanation: Birds excrete uric acid; fishes largely excrete ammonia.