Chapter 6 - LIFE PROCESSES

CHAPTER 6 -  LIFE PROCESSES

1. Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?

Answer:- Multicellular organisms such as humans possess complex body designs. They have specialized cells and tissues for performing various necessary functions of the body such as intake of food and oxygen. Unlike unicellular organisms multicellular cells are not in direct contact with the outside environment. Therefore diffusion can not meet their oxygen requirements. 

2. What criteria do we use to decide whether something is alive?

Answer:- Any visible movement such as walking, breathing or growing is generally used to decide whether something is alive or not. However, a living organism can also have movements which are not visible to the naked eye. Therefore the presence of life processes is a fundamental criterion that can be used to decide whether something is alive or not.

3. Water are outside raw materials used for by an organism?

 

Answer :- An organism uses outside raw materials mostly in the form of food and oxygen. The raw materials required by an organism can be quite varied depending on the complexity of the organism and its environment.

 

4. What processes would you consider essential for maintaining life?

 

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

 

5.  What are the differences between autotrophic nutrition and heterotrophic nutrition?

 

 

	Autotrophic nutrition		Heterotrophic nutrition
i	Food is synthesized from simple inorganic raw materials such as carbon dioxide and water.	i	Food is obtained directly or indirectly from autotrophs. This food is broken down with the help of enzymes.
ii	Presence of green pigment chlorophyll is necessary	ii	No pigment is required in this type of nutrition.
iii	Food is  generally prepared during day time	iii	Food can be prepared at all times.
vi	All green plants and some bacteria have this type of nutrition	iv	All animals and fungi have this type of nutrition

 

6. Where do plants get each of the raw materials required for photosynthesis?

 

Answer :- The following raw materials are required for photosynthesis:

 

The raw material carbon dioxide enters from the atmosphere through stomata

 

Water is absorbed from the soil by the plant roots.

 

Sunlight, an important component to manufacture food, is absorbed by the chlorophyll and other green parts of the plants.

 

7. What is the role of the acid in our stomach?

 

Answer :- the hydrochloric acid present in our stomach dissolves because of food and creates an acidic medium.  In this acidic medium, enzyme pepsinogen is converted to pepsin, which is a protein digesting enzyme.

 

8. What is the function of digestive enzymes?

 

Answer :- Digestive enzymes such as amylase, lipase, pepsin, trypsin etc.  help in the breaking down of complex food practicals into simple ones. These simple particles can be easily absorbed by the blood and thus transported to all the cells of the body.

9. How is the small intestine designed to absorb digested food?

Answer :- The small intestine has millions of tiny finger-like projections called villi. These villi increase the surface area for more efficient food absorption. Within these villi, many blood vessels are present that absorb the digested food and carry it to the blood stream. From the blood stream, the absorbed food is delivered to each and every cell of the body.