TEXTBOOK ANSWERS AND SOLUTIONS OF CBSE CLASS VII SCIENCE Chapter 2 Nutrition in Animals

1) Fill in the blanks:
(a) The main steps of nutrition in
humans are ingestion,
digestion
, absorption,
assimilation and egestion .
(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:
ANSWER 🙁 a) Digestion of starch starts in the stomach. (F)
(b) The tongue helps in mixing food with saliva. (T)
(c) The gall bladder temporarily stores bile. (T)
(d) The ruminants bring back swallowed grass into their mouth and chew
it for some time. (T)
3) Tick (P) 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
ANSWER: –   a..(iii) Small intestine
 b..Large intestine



4) Match the items of Column I with those given in Column II :
ANSWER:-
Carbohydrates                                       Sugar
Proteins                                   Amino acids
Fats                                          Fatty acid and glycerol
5) What are villi? What is their
location and function?
ANSWER:Villi are tiny finger-like projections originating from the walls
of the small intestine. They increase the surface area for absorption of the
digested food. The blood vessels present inside the villi can absorb the
nutrients
from the
digested food.
6) Where is the bile produced?
Which component of the food does it help to digest?
ANSWER:-Liver secretes the bile juice which is stored in the gall bladder.
Bile plays an important role in the digestion of fats.
7) Name the type of carbohydrate
that can be digested by ruminants but not by humans. Give the reason also.
ANSWER:-Cellulose is a type of carbohydrate that can be digested by ruminants
and not
by humans.


8) Why do we get instant energy
from glucose?
ANSWER:-Glucose is a simple sugar. Carbohydrates, when consumed, have to
be digested into glucose. As glucose can be easily absorbed in blood, it
provides energy to the body. Hence, when glucose is directly taken, it does not
have to be digested and thus acts as an instant source of energy.
9) Which part of the digestive canal is involved in?
(i) Absorption of food small
intestine
(ii) Chewing of food buccal
cavity
(iii) Killing of bacteria stomach
(iv) Complete digestion of
food small intestine
(v) Formation of faeces large
intestine
10) Write one similarity and one difference
between the nutrition in Amoeba and human beings.
ANSWER:-
Similarity: The basic process of digestion of food and release of energy is
the same in
amoeba as well
as in human beings. In amoeba, Digestive juices are secreted into the food
vacuole. They act on the food and break it down into simpler substances.
Gradually the digested food is absorbed. Similarly, in human beings various
digestive juices (mouth, stomach, intestine
etc.) act on food and break it down to simpler substances.
Difference: The digestion process in amoeba is simple while in human beings
it s a complex
process. The
process of ingestion and egestion are also quite different. Amoeba engulfs its
food by surrounding the food particle with its
pseudopodia. The undigested food which is largely carbon dioxide gas is
expelled outside by the vacuole. While in human beings, the food (which is
complex substance) is taken inside the mouth and undergoes a complex process of
digestion and absorption. Finally the undigested food it expelled in the form
of faeces.


11) Match the items of Column I
with suitable items in Column II
ANSWER:-
– Column I                                              Column II
(a) Salivary gland                              (iii) Saliva secretion
(b) Stomach                                       (iv) Acid release
(c) Liver                                              (i) Bile juice secretion
(d) Rectum                                          (ii) Storage of undigested food
(e) Small intestine                              (v) Digestion is completed
(f) Large intestine                              (vi) Absorption of water
12) Label the following figure of the digestive system.
ANSWER:-