(a) The
main steps of nutrition in humans are __________, __________, ___________,
__________ and __________
(b) The
largest gland in the human body is __________.
(c) The
stomach releases hydrochloric acid and ________ juices which act on
food.
(d) The
inner wall of the small intestine has many finger-like outgrowths called __________.
(e)
Amoeba digests its food in the __________.
Answer
1: (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.
Question 2: Mark ‘T’ if the statement is true and
‘F’ if it is false:
(a)
Digestion of starch starts in the stomach. (T/F)
(b) The
tongue helps in mixing food with saliva. (T/F)
(c) The
gall bladder temporarily stores bile. (T/F)
(d) The
ruminants bring back swallowed grass into their mouth and chew it for some
time. (T/F)
Answer 2: (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)
Question 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
Answer 3 (a) Fat is completely
digested in the
(i) stomach
(ii) mouth
(iii) small intestine √
(iv) large intestine
Answer 3 (b) Water from the
undigested food is absorbed mainly in the
(i) stomach
(ii) food pipe
(iii) small intestine
(iv) large intestine √
Question 4: Match the items of Column I with those given in Column II:
Column
I
|
Column
II
|
Food components
|
Product(s) of digestion
|
Carbohydrates
|
Fatty acids and glycerol
|
Proteins
|
Sugar
|
Fats
|
Amino acids
|
Answer 4:
|
|
Food
components
|
Product(s)
of digestion
|
Carbohydrates
|
Sugar
|
Proteins
|
Amino
acids
|
Fats
|
Fatty
acids and glycerol
|
Question 5: What are villi? What
is their location and function?
Answer 5: 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.
Structure of a villus
Question 6: Where is the bile produced? Which component
of the food does it help to digest?
Answer 6: Liver secretes the bile
juice which is stored in the gall bladder. Bile plays an important role in the
digestion of fats.
Question 7: Name the type of carbohydrate that can
be digested by ruminants but not by humans. Give the reason also.
Answer 7: Cellulose is a type of
carbohydrate that can be digested by ruminants and not by humans. Ruminants
have a large sac-like structure between small and large intestine where the
food containing cellulose is digested by the action of certain bacteria. On the
other hand, humans cannot digest cellulose, as the cellulose digesting enzymes
are absent in them.
Question 8: Why do we get instant energy from
glucose?
Answer 8: 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.
Question 9: Which part of the digestive canal is
involved in:
(i)
absorption of food ____.
(ii)
chewing of food ____.
(iii)
killing of bacteria ____.
(iv)
complete digestion of food ____.
(v)
formation of faeces ____.
Answer 9: (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.
Question 10: Write one similarity and one
difference between the nutrition in Amoeba and human beings.
Answer 10: Similarity between nutrition in Amoeba and human beings:
Both Amoeba
and humans require energy for the growth and maintenance of their bodies. This
energy is derived from the food that they eat. The food that they consume is
always in a complex form and is therefore broken down into simpler forms by the
process of digestion. Hence, both these organisms are heterotrophs.
Differences
between nutrition in Amoeba and human beings:
Digestion in Humans
|
Digestion in Amoeba
|
||
(i)
|
Humans
have a mouth and a complex digestive system.
|
(i)
|
Mouth
and digestive system are absent in Amoeba.
|
(ii)
|
Digestive
juices are secreted in the buccal cavity, stomach, and small intestine.
|
(ii)
|
Digestive
juices are secreted in the food vacuole.
|
(iii)
|
Digestion
of carbohydrates, proteins, and fats starts in separate regions.
|
(iii)
|
All the
food components are digested in the food vacuole.
|
Question 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 completed
|
|||
(f)
|
Large intestine
|
(vi)
|
Absorption of water
|
|||
-
|
-
|
(vii)
|
Release of faeces
|
|||
Answer
|
11:
|
|||||
-
|
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
|
Question 12: Label the following figure of the
digestive system.
A part of human digestive system
Answer
12:
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