Q. 94.0( 5 Votes )
The enzymes present in the saliva convert
A. fats into fatty acids and glycerol.
B. starch into simple sugars.
C. proteins into amino acids.
D. complex sugars into simple sugars.
The salivary glands present in the buccal cavity release an enzyme known as salivary amylase (ptylin). This enzyme is responsible for the breakdown of starch into simpler sugars. Hence, the process of digestion starts in our mouth itself. Further sugar digestion occurs in the stomach.
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Cellulose-rich food substances are good source of roughage in human beings becauseNCERT - Exemplar Science
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.
d. The ruminants bring back swallowed grass into their mouth and chew it for some time.NCERT Science
Label figure of the digestive system:
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 faces ________.NCERT Science
Label the following parts in Figure 2.2 and name them.
(a) The largest gland in our body.
(b) The organ where protein digestion starts.
(c) The organ that releases digestive juice into the small intestine.
(d) The organ where bile juice gets stored.NCERT - Exemplar Science
Read the following passage carefully and answer the questions that follows it. Bile juice is stored in a sac called, gall bladder, located near its organ of secretion, liver. The gall bladder releases the bile juice into the small intestine whenever food reaches there. Though bile juice is devoid of any digestive enzymes, it is required for the digestion of fats. The fats cannot be digested easily because they are insoluble in water and are present as large globules. Bile juice breaks down big fat droplets into smaller droplets. These are then easily digested by the enzymes released from the pancreas.
(a) Which organ secretes the bile juice?
(b) Why is digestion of fats difficult as compared to that of other nutrients?
(c) How does bile juice help in digestion of fat?
(d) Where is the digestion of fat completed?
(e) Does bile juice digest fat completely?NCERT - Exemplar Science
Match the organs in Column I with the words listed in Column II.
NCERT - Exemplar Science
Open your mouth, look into a mirror and try to count the different types of teeth in your mouth. Compare them with Figure 2.3 on page 13 of your NCERT textbook. Record your observations in the table below:
(a) Did you observe any difference in the number of teeth? If yes, could you identify which type of teeth showed the difference?
(b) Compare the number and type of teeth in an adult (say your parents or cousins who have reached the age of 25–30 or more). Note your observation.NCERT - Exemplar Science
Label the below given Figure 2.1 as directed below in (i) to (iv) and give the name of each type of teeth.
(i) The cutting and biting teeth as ‘A’
(ii) The piercing and tearing teeth as ‘B’
(iii) The grinding and chewing teeth as ‘C’
(iv)The grinding teeth present only in adult as ‘D’NCERT - Exemplar Science