2.
Justify the following statements:
(a) Crow is an omnivore.
(b) It is said that the mode of nutrition, in human beings and Amoeba, is quit similar.
3.
Give reasons for the following:
(a) Ingestion of food is difficult without teeth.
(b) If we chew rice, or bread, for a few minutes, it starts tasting sweet.
(c) Bacteria are present in the caecum of ruminants.
4. Explain how digested food gets absorbed into the blood.
5. State, in one/two sentence/s each, the various processes involved in nutrition in ruminant animals.
6.Explain ingestion of food, in Amoeba, through a diagram.
Answers
Answer:
Justifications -
a. Crows are omnivores. They are scavengers as well as predators and will eat virtually anything they can find. They will hunt small animals like rats and mice, smaller birds, reptiles, and eggs. Another favorite food that the crows simply love to devour is corn and sunflower seeds―especially cracked corn.
b. The basic process of digestion of food and release of energy is the same in amoeba as well as in human beings. In amoeba, digestive juices are secreted into the food vacuole. They act on the food and break it down into simpler substances.
Reasons -
a. Teeth help a lot in mechanical digestion. One of the main purposes of teeth is to break down food into smaller pieces. That is what we call mechanical digestion. They also help in chemical digestion. Chemical enzymes break down the food into even scantier bits. This process is very important to digestion. It won't be done properly without teeth as the pieces won't be small enough for the enzymes.
b. Digestion of food starts in the mouth and salivary glands present in the mouth produces digestive fluid which is called as saliva. The watery substance present in the mouth that helps in digestion is called as saliva. Saliva makes good soft and moist by mixing with it. Saliva produces an enzyme called salivary amylase that changes insoluble starch in food into soluble sugar. Rice and bread are made up of starch and when we chew rice or bread then salivary amylase changes starch into sugar. Starch is tasteless and sugar is sweet in taste. Therefore, rice or bread tastes sweet after chewing for some time.
c. Yes, it is true that bacteria are present in the caecum of ruminants. Many bacteria are present in the caecum of cows, which help in the digestion of a nutrient called cellulose which is contained by plants.
4. Digested molecules of food, as well as water and minerals from the diet, are absorbed from the cavity of the upper small intestine. The absorbed materials cross the mucosa into the blood, mainly, and are carried off in the bloodstream to other parts of the body for storage or further chemical change.
5. Not sure
6. No option to draw..