LIFE PROCESSES
Answer the following:
1. How are fats digested in our bodies? Where does this process take place?
Ans. The site of fat digestion is small intestine. Digestion of fat includes its emulsification
and then chemical digestion. Emulsification of fat is done by bile juice produced by liver.
During emulsification, larger fat drops are converted into small droplets of fats. These
fine droplets provide large surface area for the action of fat digesting enzymes. The site
of this process is small intestine. The emulsified fats are acted upon by lipase enzymes
produced by pancreas.
2. What is the role of saliva in the digestion of food?
Ans. Saliva is a watery fluid which contains salivary enzyme and mucus. Saliva moistens
and softens the food. Its amylase enzyme converts the starch of the food into a sugar.
Starch -------------------------> Sugar
Salivary amylase
Mixing of food with saliva makes swallowing easy.
3. What are the necessary conditions for autotrophic nutrition and what are its byproducts?
Ans. In autotrophic nutrition, green plants make their food by the process of
photosynthesis. This food is prepared from simple, inorganic raw materials. The
requirements for autotrophic nutrition are;
a) CO2 and H2O
b) Green coloured pigment chlorophyll for trapping energy
c) Source of energy – sunlight
By-products of photosynthesis is oxygen and water.
4. How are the alveoli designed to maximise the exchange of gases?
Ans. Structural features of alveoli to maximise the exchange of gases:
a)
b)
c)
d)
There are millions of alveoli in lungs and they have vast surface area.
Their walls are just one cell thick to facilitate diffusion.
The alveoli are richly supplied by blood they are covered by a network of capillaries.
They are kept moist and are permeable to gases.
5. What would be the consequences of a deficiency of haemoglobin in our bodies?
Ans. Haemoglobin is a respiratory pigment of our body and its function is to transport
oxygen from lungs to various parts of our body. In the deficiency of haemoglobin, the
transportation of oxygen will be affected. Tissues will not get proper amount of oxygen
and their metabolism will be affected adversely. Persons suffering from the deficiency of
haemoglobin (anaemia) get easily tired, show breathlessness and turn pale.
(will be continued….)