Nutrition in Animals
Nutrition in Animals - NCERT Guide Science Class 7
Q1: Fill in the blanks:
- The main steps of digestion in humans are _________ and ___________.
- The largest gland in the human body is _________.
- The stomach releases hydrochloric acid and ______ juices which act on food.
- The inner wall of the smaller intestine has many finger-like outgrowths called
_________.
- Amoeba digests its food in the ____________.
View Answer
Ans:
- buccal cavity, oesophagus, stomach, small intestine and large intestine
- liver
- digestive juices
- villi
- food vacuole
Q2: Mark ‘T’ if the statement is true and ‘F’ if it is false:
- Digestion of starch starts in the stomach.
- The tongue helps in mixing food with saliva.
- The gall bladder temporarily stores bile.
- The ruminants bring back swallowed grass into their mouth and chew it for sometime.
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Q3: Choose the correct option::
- Fat is completely digested in the
(i) stomach (ii) mouth (iii) small intestine (iv) large intestine
- Water from the undigested food is absorbed in the
(i) stomach (ii) food pipe (iii) small intestine (iv) large intestine
View Answer
Q4: Match the items in column I with those in column II:
| Column I |
Column II |
|
Food components
Carbohydrates
Proteins
Fats |
Products of digestion
Fatty acids and glycerol
Sugar
Amino acids
|
View Answer
Ans:
Carbohydrates ---- Sugar.
Proteins --- Amino acids.
Fats --- Fatty acids and glycerol.
Q5: What are villi ? What is their location and function ?
View Answer
Ans:
The inner wall of the small intestine has thousands finger-like outgrowths called villi.
These are found in small intestine. The villi increase the surface area for absorption of food.
Q6: Where is the bile produced ? Which component of the food does it digest ?
View Answer
Ans:
Bile is produced in liver and is stored in a sac called the gall bladder.
The bile plays an important role in the digestion of fats
Q7: Name the type of carbohydrates that can be digested by ruminants but not by humans. Give the reasons also.
View Answer
Ans:
Cellulose is the carbohydrate that can be digested by ruminants. Ruminants have large sac like structure between the small intestine and large intestine. The cellulose of the food is digested by the action of certain bacteria which are not present in human beings.
Q8: Why do we get instant energy from glucose ?
View Answer
Ans:
Because glucose easily breakdown in the cell with the help of oxygen and give carbon dioxide, water and energy
Q9: Which part of the digestive canal is involved in:
- absorption of food __________.
- chewing of food __________.
- killing of bacteria _________.
- killing of bacteria _________.
- formation of faeces ____________.
View Answer
Ans:
- small intestine
- mouth
- stomach
- small intestine
- large intestine
Q10: Write one similarity and one difference between the nutrition in amoeba and human beings.
View Answer
Ans:
Similarity: During the digestion of food, in amoeba digestive juices are secreted into the food vacuole. They act on the food and break it into simpler substances. In human being, the inner walls of stomach and the small intestine also secrete the digestive juices. The digestive juices convert complex substances of food to simpler ones.
Difference: Amoeba feeds on some microscopic organisms. When it senses food, it pushes out pseudopodia around the food particle. The food is trapped in a food vacuole. Human beings take food through the mouth, digest and utilize it. The food is gradually digested as food travels through the various compartments.
Q11: Match the items of column I with suitable items of column II:
| Column I |
Column II |
|
salivary gland
stomach
liver
rectum
small intestine
large intestine |
bile juice secretion
storage of undigested food
saliva secretion
acid release
digestion is completed
absorption of water |
View Answer
Ans:
Carbohydrates ---- Sugar.
stomach --- acid release.
liver --- bile juice secretion.
rectum --- storage of undigested food.
small intestine --- digestion is completed.
large intestine --- absorption of water.
Q12: Can we survive only on raw, leafy vegetables / grass? Discuss.
View Answer
Ans:
We know that including all animals, fungi, many bacteria, non-green plants and human being do not possess the ability to synthesize their own food. Therefore depend upon autotrophs for their food supply either directly or indirectly. The green plants (leafy vegetables / grass) trap solar energy and manufacture their food in the form of glucose. So, leafy vegetables and grass can provide sufficient energy required for the survival of human being.
