Nutrition in Animals

1. Fill in the blanks:a. The main steps of digestion in humans are ingestion, digestion, absorption, assimilation andegestion.b. The largest gland in the human body is liver.c. The stomach releases hydrochloric acid and digestive juices which act on food.d. The inner wall of the small intestine has many finger-like outgrowths called villi.e. Amoeba digests its food in the food vacuole.

2. Mark ‘T’ if the statement is true and ‘F’ if it is false:a. Digestion of starch starts in the stomach. Falseb. The tongue helps in mixing food with saliva. Truec. The gall bladder temporarily stores bile. Trued. The ruminants bring back swallowed grass into their mouth

and chew it for some time. True

3. Tick () mark the correct answer in each of the following:a. Fat is completely digested in the-

i. Stomach ii. Mouth iii. Small intestine iv. Large intestine

b. Water from the undigested food is absorbed mainly in the-i. Stomach ii. Food pipe iii. Small intestine iv. Large intestine

4. Match the items of Column I with those given in Column II:Column I Column IIFood components Product(s) of digestionCarbohydrates Fatty acids and glycerolProteins SugarFats Amino acids

5. What are Villi? What is their location and function?Villi are small finger like out growths in the inner walls of the smallintestine. These villi increase the surface area for proper absorption of thefood.

6. Where is the bile produced? Which component of the food does it digest?Bile juice is produced in the liver. Bile does not digest any food but it helps in digestion of fatsand oils by breaking them into fine droplets for easy digestion.

8. Name the type of carbohydrate that can be digested by ruminants but not by humans.Give the reason also.Cellulose is a complex carbohydrate, which can be digested byruminants but not by humans. Ruminants have a large sac like structurecalled rumen in which cellulose containing food is digested by the actionof bacteria.

Rumen9. Why do we get instant energy from Glucose?We get instant energy from Glucose because in the cells, glucose breaks down with the help ofoxygen into carbon dioxide and water, and energy is released. The process can be shown in thefollowing manner- In Cells

Glucose + Oxygen Carbon dioxide + Water + Energy

10. Which part of the digestive canal is involved in?i. Absorption of food- Small Intestine.ii. Chewing of food- Teeth in the mouth.iii. Killing of bacteria- Acid in the stomach.iv. Complete digestion of food- Small Intestine.v. Formation of faeces- Large Intestine.

11. Write one similarity and one difference between the nutrition in Amoeba and humanbeings.Similarity between nutrition in Amoeba and Human beings-a. Both Amoeba and Human beings are heterotrophic i.e., they cannot make their own food andtake food from outside.b. In both Amoeba and Human beings the steps of nutrition are the same i.e., ingestion,digestion, absorption, assimilation and egestion.c. Both Amoeba and Humans consume solid food.Difference between nutrition in Amoeba and Human beings-In human beings food is digested in different parts such as- stomach, small intestine, largeintestine etc.

12. Match the items of Column I with suitable items in Column IIColumn I Column IIa. Salivary gland i. Bile juice secretionb. Stomach ii. Storage of undigested foodc. Liver iii. Saliva secretiond. Rectum iv. Acid releasee. Small intestine v. Digestion is completedf. Large intestine vi. Absorption of water

vii. Release of faeces

13. Label Fig. 2.11 of the digestive systemOesophagus

Gall Bladder Stomach

Pancreas

Small Intestine

Large Intestine

RectumAnus

14. Can we survive only on raw, leafy vegetables/grass? Discuss.No, we cannot survive only on by eating raw, leafy vegetables/grass because by eating raw leafyvegetables we would get sufficient amounts of vitamins, minerals and fibre but our body alsoneeds proteins, carbohydrates and fats, which are in very little amounts in raw leafy vegetables.So, we have to eat other food materials such as rice, wheat, potatoes, pulses, milk, butter andghee, which would supply us sufficient amounts of proteins, carbohydrates and fats.

We cannot eat grass as food because grass contains cellulose as carbohydrate, which we cannotdigest. Only herbivore animals like cows and buffaloes can use grass as food because they candigest cellulose with the help of bacteria in their stomach.

15. What do you mean by digestion?The breakdown of complex components of food into simpler substances is called digestion. Forexample- Proteins are complex components of food. They are digested to amino acids, which areabsorbed by the small intestine.

16. What organs does the human digestive system consist of?The human digestive system consists of the alimentary canal and secretory glands. It consists of-a. Buccal Cavity (Mouth)b. Oesophagusc. Stomachd. Small Intestinee. Large Intestine ending in rectum andf. Anus.The main digestive glands, which secrete digestive juices, are-a. The Salivary Glandsb. The Liver andc. The Pancreas.

17. What is Ingestion?The process of taking food into the body (mouth) is called ingestion.

18. Explain the process of feeding and digestion in Amoeba.Amoeba ingests its food with the help of its false feet or Pseudopodia. The food is digested in thefood vacuole. The digested food is absorbed and the undigested waste of the food is removedoutside by the vacuole.

Food VacuolesFood Particle

Egested Waste (Ingestion)

Nucleus Pseudopodium

19. What is assimilation?The absorbed substances are transported by the blood vessels to different organs of the bodywhere they are used to build complex substances such as the proteins required by the body. Thisis called assimilation.

20. Name the nutrient digested in the stomach? FoodProteins are digested in the stomach.

Oesophagus21. What is the shape of the stomach?The stomach is a thick walled bag. Its shape is like a flattenedU and it is the widest part of the alimentary canal.

Stomach22. What is Cud?The partially digested food stored in the rumen is called cud.

23. What is Rumination?In ruminants such as cows and buffaloes the cud returns to the mouth in small lumps and theanimal chews it. This process is called rumination.K. P. Singh, Biology Department, Delhi Public School, Mathura Refinery Nagar, Mathura