Question Bank — Structural Organisation in Animals

QUESTION BANK

Class 11 Biology – Chapter 7: Structural Organisation in Animals
(Strictly based on NCERT text)

Section A — MCQs (1 mark each)

1. Which of the following statements about frog skin is correct?
   (a) It is dry and scaly
   (b) It is smooth, slippery and always kept moist by mucus
   (c) It is thick and impermeable
   (d) It lacks blood vessels

2. The heart of frog consists of:
   (a) Two atria and two ventricles
   (b) One atrium and one ventricle
   (c) Two atria and one ventricle
   (d) One atrium and two ventricles

3. Assertion (A): Frogs are called ureotelic animals.
   Reason (R): They excrete nitrogenous waste in the form of urea.
   (a) Both A and R are true and R is the correct explanation of A
   (b) Both A and R are true but R is not the correct explanation of A
   (c) A is true but R is false
   (d) A is false but R is true

4. Assertion (A): Frogs exhibit cutaneous respiration both in water and on land.
   Reason (R): Their skin is highly vascularised and remains moist.
   (a) Both A and R are true and R is the correct explanation of A
   (b) Both A and R are true but R is not the correct explanation of A
   (c) A is true but R is false
   (d) A is false but R is true

5. The cloaca in frog is:
   (a) A chamber that receives only digestive waste
   (b) A common chamber for digestive, excretory and reproductive products
   (c) Absent in both male and female frogs
   (d) Connected directly to the urinary bladder only

6. Which structure joins the right atrium in the frog’s heart?
   (a) Conus arteriosus
   (b) Sinus venosus
   (c) Pericardium
   (d) Bidder’s canal

7. The ability of frog to change colour for protection is called:
   (a) Hibernation
   (b) Aestivation
   (c) Mimicry
   (d) Metamorphosis

8. In frog, hepatic portal system connects:
   (a) Kidney and lower body parts
   (b) Liver and intestine
   (c) Heart and lungs
   (d) Brain and spinal cord

9. Number of cranial nerves in frog is:
   (a) 8 pairs
   (b) 10 pairs
   (c) 12 pairs
   (d) 9 pairs

10. Which of the following is absent in female frog?
    (a) Oviduct
    (b) Vocal sacs
    (c) Urinary bladder
    (d) Cloaca

Section B — Very Short Answer (2 marks each)

1. Define tissue. Give one example from the chapter.
2. What is the difference between aestivation and hibernation in frogs?
3. Name the two special venous connections present in the frog’s circulatory system.
4. State two features that distinguish male frog from female frog.
5. What is the function of the nictitating membrane in frog?
6. Why is the alimentary canal short in frog?

Section C — Short Answer (3 marks each)

1. Describe the morphology of the skin and body of frog as given in the NCERT text.
2. Explain the process of digestion in the stomach and duodenum of frog.
3. Differentiate between pulmonary respiration and cutaneous respiration in frog.
4. Describe the structure of the brain of frog.
5. Write three points about the excretory system of frog.

Section D — Long Answer (5 marks each)

1. Describe the complete digestive system of frog with the help of a labelled diagram. (Diagram – 2 marks; description of parts and functions – 3 marks)
2. Describe the male and female reproductive systems of frog. How does external fertilisation occur?
3. Explain the closed blood vascular system of frog. Add a note on the hepatic portal and renal portal systems.

Section E — Case/Source-Based (4 marks each)

Case 1

During peak summer and winter, frogs are rarely seen in fields or ponds. They remain inactive inside deep burrows. On land they respire through skin, buccal cavity and lungs, while in water only skin is used. Their skin remains moist due to mucus glands.

Sub-questions:
(a) Name the phenomenon of summer sleep and winter sleep in frogs. (1)
(b) Which respiratory organ is common during both aestivation and hibernation? (1)
(c) Why does the frog need to keep its skin moist? (1)
(d) Mention one advantage of cutaneous respiration for an amphibian. (1)

Case 2

A mature female frog can lay 2500–3000 ova at a time. Fertilisation occurs outside the body in water. The larva that hatches is called tadpole, which later undergoes metamorphosis to become an adult frog. Frogs also help farmers by feeding on insects.

Sub-questions:
(a) What type of fertilisation is seen in frog? (1)
(b) Name the larval stage of frog. (1)
(c) State any two ways in which frogs are beneficial to mankind according to the chapter. (1)
(d) Why is the number of ova produced by a female frog so high? (1)