Q. Why do you think:
a. curd set faster in summer than in winter.
b. Curd turns sour faster in summer than in winter
Answer: (a) Bacteria grow faster in summer, as they require warm temperatures to grow. Thus, they set curd faster in summer than in winter.
(b) Curd turns sour faster in summer than in winter because during summer, the temperature is high, which allows the bacteria to grow and multiply faste
Q. The sealed packets in which food items such as chips are sold are usually filled with nitrogen. How do you think that help?
Answer : Nitrogen prevents the growth of microorganisms as microorganisms need oxygen for their growth and survival. In this way, the food items are prevented from being spoilt by microorganisms.
Q. Why should you always wash our hands before handling food and after using the toilet
Answer: We should always wash our hands before handling food and after using the toilet to remove the germs from our hands. If we eat food without washing our hands, there is a chance that the germs may enter our body, causing infections.
Q. why does bacterias become resistant to antibiotics within our own life time
Answer : Evolution occurs quickly in bacteria, as bacteria reproduce faster than other organisms. Some bacteria may reproduce as fast as every 20 minutes, which is halfamillion times faster than humans. This is the reason why bacteria become resistant to antibiotics within our own life time.
Q. How do viruses caused diseses?
Answer : A virus enters the living cell of an organism and uses the resources inside the host cell for its reproduction. It duplicates itself and then the host cell dies and finally bursts. The newly formed virus released from that cell starts invading the other cells. This process is repeated and in this way, many cells of the host organism are destroyed. As large numbers of host cells are destroyed, the person becomes ill.
Q. Which organism act as decomposer? How is this activity helpful to us?
Answer : Bacteria, protozoa and fungi act as decomposers. These decomposers break down organic matter present in the bodies of dead plants and animals into simple substances and mix them in the soil. A plant growing in this soil absorbs the nutrients and passes them to the animals that consume the plant products. Thus, these microorganisms act as decomposers and help in recycling the nutrients in the soil.
More solved Questions Visit
Micro organism class 8 laboratory experiment