D. Short Answer Type Questions
1. How does Amoeba capture food?
2. What is the role of hydrochloric acid in the stomach?
3. (a) Which movements are produced in the wall of alimentary canal?
(b) How are they produced?
(c) What is their role in digestion?
4. How does bile juice help in digestion of food?
5. (a) Why are cows and buffaloes called ruminants?
(b) Where does digestion of cellulose take place?
6. Name the parts of ruminant stomach. Which of these represents the true stomach?
7. What are saprophagous animals? Give their examples.
8. What is meant by assimilation? How are different nutrients assimilated?
9. How is cellulose digested in ruminants?
Answers
Explanation:
1.Amoeba envelops their food through endocytosis or phagocytosis, where the flexibility of the plasma membrane creates pseudopodia. The pseudopodia are the temporary arm-like projection in the amoeba that helps collect nutrition, alter its size and shape, and act as a locomotion organ.
2.The hydrochloric acid in the gastric juice breaks down the food and the digestive enzymes split up the proteins. The acidic gastric juice also kills bacteria. ... Together with the bicarbonate, this ensures that the stomach wall itself is not damaged by the hydrochloric acid.
3.(a)The movements produced in the alimentary canal are called peristaltic movements.
(b) Human digestive system comprises the alimentary canal and various digestive glands. The alimentary canal is a muscular tube, which extends from the mouth to the anus. The human digestive system comprises mouth, pharynx, oesophagus, stomach, small intestine, large intestine, and anus.
(c) The alimentary canal performs the function of digesting food. It breaks it down to smaller pieces and aids in the absorption of the digested food.
4.Bile is a fluid that is made and released by the liver and stored in the gallbladder. Bile helps with digestion. It breaks down fats into fatty acids, which can be taken into the body by the digestive tract.
5.(a)Cows are known as “ruminants” because the largest pouch of the stomach is called the rumen. ... This process of swallowing, “un-swallowing”, re-chewing, and re-swallowing is called “rumination,” or more commonly, “chewing the cud.” Rumination enables cows to chew grass more completely, which improves digestion.
(b) The rumen is the first compartment where ingested food containing cellulose is stored temporarily and later regurgitated to chew their cud. They are able to digest cellulose because of the presence of bacteria and enzymes in the rumen where anaerobic bacterial digestion occurs.
6.The true ruminant stomach consists of four compartments: the rumen, reticulum, omasum, and abomasum.
7.Saprophages are organisms that obtain nutrients by consuming decomposing dead plant or animal biomass. ... Typical saprophagic animals include sedentary polychaetes such as amphitrites (Amphitritinae, worms of the family Terebellidae) and other terebellids. The eating of wood, whether live or dead, is known as xylophagy
8.The absorption and digestion of food or nutrients by the body or any biological system is called assimilation.
Assimilation is the process of absorbing nutrients during digestion and distributing them to the body for growth and repair. The small intestine uses microvilli to absorb nutrients. ... The large intestine moves water by osmosis to the blood. The blood then carries water to the rest of the body.
9.Ruminant Digestion. Like other vertebrates, ruminant Artiodactyla (including cattle, deer, and their relatives) are unable to digest plant material directly, because they lack enzymes to break down cellulose in the cell walls. Digestion in ruminants occurs sequentially in a four-chambered stomach.