Nutrition in Animals
Chapter 2
1. Fill in the blanks:
(a) The main steps of nutrition in humans are __________ . ____________ . _____________. ___________and ______________. .
Ans: Ingestion, Digestion, Absorption, Assimilation, Egestion .
(b) The largest gland in the human body is ____________.
Ans: liver .
(c) The stomach releases hydrochloric acid and _____________juices which act on food .
Ans: digestive .
(d)The inner wall of the smalls intestine has many finger -like outgrowths called____________.
Ans: villi.
(e)Amoeba digest its food in the ______________.
Ans: food vacuole.
2. Mark ''T'' if the statement is true and "F" if it is false:
(a) Digestion of starch starts in the stomach. (T/F)
Ans: False .
(b) The tongue helps in mixing food with saliva .(T/F)
Ans: True .
(c) The gall bladder temporarily stores bile. (T/F)
Ans: True .
(d) The ruminants bring back swallowed grass into their mouth and chew it for some time. (T/F)
Ans: 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
Ans: (iii) small intestine
(b) Water from the undigested food is absorbed mainly in the
(i) stomach (ii) foodpipe (iii) small intestine (iv) large intestine
Ans: (iv) large intestine
4.Match the items of Column I with those given in Column II:
Column I Column II
i) Food components a)Product(s) of digestion
ii)Carbohydrates b)Fatty acids and glycerol
iii) Proteins c)Sugar
iv) Fats d)Amino acids
Ans:
| i)Food components | a)Products of digestion |
|---|---|
| ii)Carbohydrates | c)Sugar |
| iii)Proteins | d)Amino acids |
| iv)Fats | b)Fatty acids and glycerol |
5. What are villi? What is their location and function?
Ans: Villi are tiny finger-like projections that line the inner wall of the small intestine. They are microscopic, but incredibly numerous, with estimates ranging from 10 to 40 villi per square millimeter of tissue! Their main function is to maximize the surface area available for absorption of nutrients from digested food into the bloodstream. The increased surface area created by these villi is crucial for efficient nutrient uptake.
Here's a closer look at villi and their role in nutrient absorption:
- Structure: Each villus is covered in a single layer of epithelial cells, further enhancing the surface area for absorption. Within these villi are also tiny blood vessels and a lacteal, a specialized lymphatic vessel that absorbs fats.
- Nutrient Absorption: As digested nutrients like sugars, amino acids, and fatty acids pass through the small intestine, they are absorbed by the villi. The sugars and amino acids enter the bloodstream directly through the capillaries within the villi. Fatty acids and glycerol take a slightly different route; they are packaged into chylomicrons and absorbed by the lacteal, entering the lymphatic system before eventually reaching the bloodstream.
6. Where is the bile produced? Which component of the food does it help to digest?
Ans: 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.
7. Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.
Ans: The type of carbohydrate that can be digested by ruminants but not by humans is cellulose.
Here's why:
- Cellulose Structure: Cellulose is a complex carbohydrate with a strong beta-1,4 glycosidic linkage between its glucose units. This linkage is difficult for human digestive enzymes to break down.
- Human Digestive System: Humans lack the enzymes necessary to break down these beta-1,4 glycosidic linkages in cellulose. As a result, cellulose passes through our digestive system largely undigested.
- Ruminant Digestive System: Ruminants, on the other hand, have a unique digestive system adapted for processing tough plant material like grass. Their complex stomach compartments house specialized microbes that can break down cellulose. These microbes produce enzymes like cellulase, which can break down the beta-1,4 glycosidic linkages in cellulose, allowing ruminants to extract energy from this carbohydrate source.
9. Which part of the digestive canal is involved in:
(i)) absorption of food ________________.
Ans: small intestine.
(ii) chewing of food ________________.
Ans: Mastication .
(iii) killing of bacteria ________________.
Ans: bactericide.
(iv) complete digestion of food ________________.
Ans: small intestine.
(v) formation of faeces ________________.
Ans: large intestine.
10.Write one similarity and one difference between the nutrition in amoeba and human beings
and human beings.
Ans: Similarity: Both amoeba and humans are heterotrophs, meaning they obtain their nutrients from other organisms. They cannot produce their own food and must consume other living things or organic matter.
Difference: The complexity of their digestive systems is vastly different. Amoeba uses a simple method where it engulfs food particles with its pseudopodia (finger-like projections) into a food vacuole inside its cell. There, digestive enzymes break down the food. Humans have a complex digestive system with specialized organs like the mouth, stomach, and intestines. Food travels through this system, undergoing mechanical and chemical breakdown before nutrients are absorbed and waste is eliminated.
11. Match the items of Column I with suitable items in Column II
Column I Column II
(a) Salivary gland (i) Bile juice secretion
(b) Stomach (ii) Storage of undigested food
(c) Liver (iii) Saliva secretion
(d) Rectum (iv) Acid release
(e) Small intestine (v) Digestion is co
Ans: Column I Column II
(a) Salivary gland (iii) Saliva secretion
(b) Stomach (iv) Acid release
(c) Liver (i) Bile juice secretion
(d) Rectum (vii) Release of faeces
(e) Small intestine (v) Digestion is completed
1. Visit a doctor and find out:
(i) Under what conditions does a patient need to be on a drip of glucose?
Ans: Hypoglycemia and Dehydration .
(ii) Till when does a patient need to be given glucose?
Ans: The patient should be given a glucose drip until his or her normal blood glucose level is restored,
(iii) How does glucose help the patient recover?
Write the answers in your notebook
Ans: It provides instant energy to all the organs of the body to perform their functions. Thus, it helps the patient to recover fast.
2.Find out what vitamins are and get the following information.
(i) Why are vitamins necessary in the diet?
Ans: Vitamins and minerals are essential for bodily functions such as helping to fight infection, wound healing, making our bones strong and regulating hormones.
(ii) Which fruits or vegetables should be eaten regularly to get vitamins?
Write a one-page note on the information collected by you. You may take
help of a doctor, a dietician, your teacher or any other person, or from
any other source.
Ans: Oranges, spinach, carrots, berries, and broccoli are just a few examples of fruits and vegetables that are rich in vitamins and should be consumed regularly. By incorporating these nutritious foods into our daily meals, we can ensure that our bodies receive the necessary vitamins to maintain optimal health.
3. Collect data from your friends, neighbours and classmates to know more about “milk teeth”.
Tabulate your data. One way of doing it is given below:
Find out from at least twenty children and find the average age at which children lose the milk teeth. You may take help of your friends.
Type by Jyotishna Hazarika
