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Question
Give a reason.
Food becomes acidic in the stomach.
Solution
Food becomes acidic in the stomach because of the presence of hydrochloric acid. As the food reaches the stomach, it gets mixed with the hydrochloric acid present there. The hydrochloric acid plays the following roles in digestion:
- It initiates protein digestion by activating the conversion of pepsinogen to pepsin.
- It provides an acidic medium for the activity of pepsin and other enzymes present in gastric juice.
RELATED QUESTIONS
Pancreatic juice contains enzymes which digest:
(a) proteins and carbohydrates only
(b) proteins and fats only
(c) fats and carbohydrates only
(d) proteins, fats and carbohydrates
If the teeth are not cleaned regularly, they become covered with a sticky yellowish layer W of food particles and bacteria. Since layer W covers the teeth, the alkaline liquid X secreted by glands Y inside the mouth cannot reach the teeth surface to neutralise the acid formed by the action of organisms Z on sugary food, and hence tooth decay sets in.
(a) What is W known as?
(b) What is (i) X, and (ii) Y?
(c) What are organisms Z?
(d) State one way of removing layer W from the teeth.
Prepare a possible vegetarian menu for your dinner which would provide all the necessary nutrients.
Write short answers
Write the names of three enzymes which are found in pancreatic juice.
Name different steps involved in animal nutrition. Explain.
What is the length of the alimentary canal?
Which sphincter guards the opening of the hepato-pancreatic duct?
In which part of the alimentary canal food is finally digested?
Draw the diagram of the alimentary canal of man and label the following parts. Mouth, Oesophagus, Stomach, Intestine.
______ is the vestigeal organ in human.
