Page 91 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

4. Name and write about the two types of respiration.

Ans. Anaerobic respiration

During aerobic respiration, glucose is completely broken down. Carbon dioxide, water
and energy is released in this process. This breakdown of glucose occurs because of

oxygen.

C H O + 6O  6CO + 6H O + 38 ATP
6 12 6 2 2 2
(Glucose (food)) + (Oxygen)  (Carbon dioxide) + (Water) + (Energy)

This type of respiration releases maximum amount of energy.

Anaerobic respiration
Anaerobic respiration refers to the breakdown of glucose to release energy in the

absence or lack of oxygen. Energy released in anaerobic respiration is much less than

energy released in aerobic respiration.
Anaerobic respiration in yeast: Yeast breaks down glucose in the absence of oxygen

to release energy along with the production of ethanol and carbon dioxide.

C H O  2C H OH + 2CO + 2ATP
6 12 6 2 5 2
(Glucose)  (Ethanol) + (Carbon dioxide) + (Energy)
5. It is not wise to sleep under a tree at night. Why?

Ans. Plants respire throughout the day and also at night. In the daytime, the released

carbon dioxide is used by plants for photosynthesis. However at night, only carbon
dioxide is released into the atmosphere through stomata as no photosynthesis

occurs.

6. Write the difference between anaerobic respiration in plants and in human beings.
Also write the equation for both.

Ans. Plants can perform anaerobic respiration, primarily in roots under certain conditions

like water logging, where oxygen availability is limited. The end products of anaerobic

respiration in plants are usually ethonol and carbon dioxide.
C H O  2C H OH + 2CO + 2 ATP
6 12 6 2 5 2
Glucose Ethanol Carbon dioxide Energy

Human beings perform anaerobic respiration particularly in muscle cells during
intense exercise when oxygen demand is not fulfilled. The end product of anaerobic

respiration in humans is lactic acid.

C H O  Lactic Acid + 2 ATP
6 12 6
Glucose (Energy)

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