How are fats digested in our bodies? Where does this process take place?

During the respiration of an organism A, 1 molecule of glucose produces 2 ATP molecules whereas in the respiration of another organism B, 1 molecule of glucose produces 38 ATP molecules.

1. Which organism is undergoing aerobic respiration?
2. Which organism is undergoing anaerobic respiration?
3. Which type of organism, A or B, can convert glucose into alcohol?
4. Name one organism which behaves like A.
5. Name two organisms which behave like B.

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

1. Glucose → Respiration → Respiration Ethanol + Carbon-dioxide + Energy.
2. Glucose → Respiration → Respiration Carbon-dioxide + Water + Energy.
3. Glucose → Respiration → Respiration Lactic acid + Energy.

1. Name one organism which respires according to equation (i) above.
2. Name one organism which respires according to equation (ii) above.
3. When and where does respiration represented by equation (iii) above take place?
4. Which equation/ equations represent aerobic respiration?
5. Which equation/ equations represent anaerobic respiration?
6. Which of the above reactions produces the maximum amount of energy?

Draw a neat labelled diagram of the human excretory system.

Mention the major events during photosynthesis.

1. Define excretion.
2. Name the basic filtration unit present in the kidney.
3. Draw excretory system in human beings and label the following organs of excretory system which perform following functions:

1. Form urine.
2. Is a long tube which collects urine from kidney.
3. Store urine until it is passed out.

What are the different modes of nutrition? Explain with one example of each mode of nutrition.

A unicellular animal P having no fixed shape ingests a food particle by forming temporary finger-like projections Q. The food particle is engulfed with a little surrounding water to form a temporary stomach R inside it. The chemicals S from surrounding cytoplasm enter into R and break down food into small and soluble molecules by chemical reactions. The digested food is absorbed directly into cytoplasm by the process T. The undigested food is thrown out of the body by the rupture of a cell organelle U in a process called V.

1. Name the unicellular animal P.
2. What are (i) Q, and (ii) R?
3. Name (i) chemical S, and (ii) process T.
4. Name (i) organelle U, and (ii) process V.

An organism X having breathing organs A lives on land. When organism X goes under water, it cannot survive for a long time unless carrying an oxygen cylinder. On the other hand, the organism Y having breathing organs B always lives in water and if taken out of water, it dies after a short while. A third organism Z having breathing organs C and D which lives on the banks of ponds, lakes and rivers can survive on land as well as in water equally well.

1. What could organism X be? Name the breathing organs A.
2. What could organism Y be? Name the breathing organs B.
3. What could organism Z be? Name the breathing organs C and D.
4. Out of X, Y and Z, which organism is.

1. Amphibian,
2. Aquatic,
3. Terrestrial?

Describe double circulation in human beings. Why is it necessary?