Some sugar solution is taken in a test-tube and a little of substance X in powder form is added to it. The mouth of test-tube is closed with a cork and allowed to stand for some time. On opening the cork, a characteristic smell of substance Y is obtained and a gas Z is also observed to be formed. The gas Z extinguishes a burning matchstick.

(a) What could be (i) X, (ii) Y, and (iii) Z ?

(b) What is the process of converting sugar into substance Y by the action of X known as? (c) What type of respiration is exhibited by X in the above process ?

A, Band Care three living organisms. The organism A is a unicellullar fungus which can live without air. It is used in the commercial production of an organic compound P from molasses. The organism B is a unicellular animal which lives in water and feeds and moves by using pseudopodia. It breathes through an organelle Q. The organism C is a tiny animal which acts as a carrier of malarial parasite. It breathes and respires through a kind of tiny holes Rand air-tubes Sin its body.

(a) What are organisms (i) A (ii) B, and (iii) C?

(b) Name (i) P (ii) Q (iii) R, and (iv) S.

(c) Which organism/ organisms undergo aerobic respiration?

(d) Which organism/ organisms undergo anaerobic respiration?

There are five animals P, Q R, S and T. The animal P always lives in water and has gills for breathing. The animal Q can stay in water as well as on land and can breathe both, through moist skin and lungs. The animal R lives in soil and breathes only through its skin. The animal S lives on land and breathes through spiracles and tracheae. And animal T lives in water and breathes through its cell membrane.

(a) Which of the animals could be Amoeba?

(b) Which of the animals could be frog?

(c) Which animal could be fish?

(d) Which animal could be grasshopper?

(e) Which animal could be earthworm?

Consider the following chemical reactions which take place in different organisms/tissues under various conditions:

(i) Glucose Ethanol + Carbon dioxide + Energy

(ii) Glucose Carbon dioxide + Water + Energy

(iii) Glucose Lactic acid + Energy

(a) Name one organism which respires according to equation (i) above.

(b) Name one organism which respires according to equation (ii) above.

(c) When and where does respiration represented by equation (iii) above take place?

(d) Which equation/equations represent aerobic respiration ?

(e) Which equation/equations represent anaerobic respiration ?

(f) Which of the above reactions produces the maximum amount of energy ?

When a person breathes in air, the air enters into his body through an organ A having two holes B in it. The air then passes through pharynx and larynx and enters into a tube C. The tube C divides into two smaller tubes D at its lower end. The two smaller tubes are attached to two respiratory organs E. Each smaller tube divides inside the organs E to form a large number of still smaller tubes called F. The smallest tubes F have air-sacs G at their ends in which gaseous exchange takes place in the body of the person. What are A, B, C, D, E, F and G?