Question

1. Answer the following questions in 10–20 words: (2 marks)

a) Mehaa filled a container with dough and added yeast to it. She kept it aside for a few

days. Write down the reaction that will take place in the container.

b) How does the diaphragm move during inhalation?

2. Choose the correct option: (2 marks)

a) The primary function of enzymes in the saliva is to convert:

(i) fats into fatty acids and glycerol (ii) starch into simple sugars

(iii) proteins into amino acids (iv) complex sugars into simple sugars

b) The cell membrane of an amoeba changes its shape to trap food. What are these

structures called?

(i) cud (ii) vacuole

(iii) pseudopodia (iv) cell wall

3. Answer the following questions in 30–40 words: (8 marks)

a) Rahul placed his potted plant in a dark room. A few days later, he noticed that the

plant had died. Why do you think this happened?

b) Describe two differences between the digestive system of grass-eating animals and

humans.

c) Adi measured his breaths per minute when at rest and when playing football, as

shown below. Why does the number of breaths per minute change?

d) Distinguish between aerobic and anaerobic respiration.​

Answer 1

Answer:

3)d:Aerobic respiration:

It is a set of metabolic reactions that take place in the presence of oxygen occuring in a cell to convert chemical energy into ATPs.

Anaerobic respiration:

It is the process of cellular respiration where the high energy electron acceptor is neither oxygen.