Page 24 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

• Egestion : The food that remains undigested in the small intestine moves into the

large intestine. The large intestine absorbs water and salts from the undigested

food. The remaining waste passes into the rectum and remains there as semi-
solid faeces. The faecal matter is removed through the anus timely.

2. Write a short note on digestion in grass-eating animals.

Ans. Digestion in grass- eating animals
Grass-eating animals are also called ruminants. They have unique digestive system

adapted to break down cellulose, which is present in grass.
The process starts when ruminants eat grass and chew it briefly before swallowing

it into the first chamber of the stomach, the rumen. In the rumen, bacteria and

microbes help in breaking down the cellulose in the grass. This partially digested
food then moves to the reticulum, where it forms small lumps called cud. The cud is

regurgitated, re-chewed and swallowed again. The food then passes into the omasum,
where water and nutrients are absorbed. Finally the food reaches the abomasum,

the true stomach, where digestive enzymes and acids break down proteins and kill

microbes from the rumen, making the remaining nutrients more accessible. The
digested material them moves into the intestines, where most nutrient absorption

occurs.

3. Write one similarity and one difference between the nutrition in Amoeba and human
beings.

Ans. Similarity: Both amoeba and human beings obtain nutrients through the process of

digestion. In amoeba, food particles are engulfed and digested within food vacuoles,
whereas in humans food is ingested and broken down in the digestive system into

simpler substances that can be absorbed by the body.
Difference : Amoeba digests food intracellularly. It means digestion occurs within

individual calls, specifically with in food vacuoles. In contrast, human beings digest

food outside the cells within the digestive tract, which includes organs such as the
stomach and intestines.

4. Name the glands associated with alimentary canal and write their role in digestion.
Ans. The glands associated with the alimentary canal and their roles in digestion are as

follows?

Salivary glands : These glands secrete saliva into the mouth. Saliva contains the
enzyme amylase, which begins the process of breaking down starch into simple

sugar. Saliva also moistens food, making it easier to chew and swallow.

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