NCERT In Text

What processes would you consider essential for maintaining life?

Life processes such as nutrition, respiration, transportation, excretion, etc. are essential for maintaining life.

Related Questions Life Processes

The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm.
(b) mitochondria.
(c) chloroplast.
(d) nucleus.

Ans: (b) mitochondria.

Aerobic respiration  

Anaerobic respiration

1. Oxygen is utilised for the breakdown of respiratory substrate. 1. Oxygen is not required.
2. It takes place in cytoplasm (glycolysis) and inside mitochondria (Krebs cycle) 2. It takes place in cytoplasm only.
3. End products are carbon dioxide and water 3. End products are lactic acid or ethanol and carbon dioxide.
4. More energy is released. 4. Less energy is released.

This is an incorrect statement. All plants carry on respiration throughout 24 hours and thus give out carbon dioxide throughout the 24 hours. But photosynthesis happens only in presence of sunlight and oxygen is released during daytime.

Enzymes break-down the various complex components of food into simple and soluble components so that they can be absorbed easily.

Alveoli provide a surface for the exchange of gases. An extensive network of blood vessels is present in the wall of the alveoli. By lifting our ribs and flatten the diaphragm, the chest cavity becomes spacious. Air is sucked into the lungs and alveoli. The oxygen from the breath, diffuses into the blood and CO2 from the blood brought from the body, diffuses out into the air.