Question1.Choose the correct option
A. The type of nutrition in which animals consume the solid or liquid food which is later broken down by the body is called _______
(i)parasitic nutrition (ii) saprotrophic nutrition (iii) symbiotic nutrition (iv) holozoic nutrition
Answer. holozoic nutrition
b. organism X is a parasite. It obtains its nutrition from inside the body of the host. Identify ORGANISM x
(a) Tick (b) Hookworm (c) Leech (d) Mite
Answer. Hookworms
c. Which part of the human teeth that is richly supplied with blood vessels and nerves?
(a) Dentine (b) Crown (c) Pulp (d) Root
Answer. (c) Pulp
d. Which part of the stomach stores cud in ruminants?
(a) Rumen (b)Reticulum (c)Omasum (d) Abomasum
Answer. (b)Reticulum
Question2.Assertion- reasoning questions.
for questions number (i) to (iii) two statements are given one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (a), (b), (c), (d) as given below
(a)both assertion and reason are true, and reason R is the correct explanation of the assertion (A).
(b) both assertion and reason are true and reason R is not the correct explanation of the assertion (A).
(c) Assertion (A) Is true, but Reason (R) is false.
(d) Assertion (A) Is false, but Reason (R) is true.
(i)Assertion: Gastric juices secreted by the stomach contains hydrochloric acid.
Reason: Hydrochloric acid provides the acidic environment necessary for digestion of food.
(ii)Assertion: (A) Our mouth has the salivary glands which secrete saliva.
Reason (R) The saliva has no action on the food we eat.
(iii) Assertion:(A)Bacteria present in our mouth act on the food particles present in the gaps between our teeth and form plaque.
Reason (R) Plaque converts sugar and starch in the food items into acids.
(a) is correct: both assertion and reason are true, and reason R is the correct explanation of the assertion (A). means this option (i)Assertion: Gastric juices secreted by the stomach contains hydrochloric acid.
Reason: Hydrochloric acid provides the acidic environment necessary for digestion of food.
Question3.Answer the following question in one sentence
(a). What is chemical digestion ?
Answer. Chemical digestion is the process in which enzymes break down food molecules into smaller, absorbable nutrients.
(b)State the function of the epiglottis
Answer. The function of the epiglottis is to prevent food or liquid from entering the trachea during swallowing by covering the opening of the windpipe.
(c ) In which part of the alimentary canal does the absorption of water takes place?
Answer. Absorption of water primarily takes place in the large intestine of the alimentary canal.
Question4. Answer the following question in 2-3 sentences.
- Name the organ that secretes bile and the one that stores it. State the function of bile.
Answer. The liver secretes bile, which is stored in the gallbladder. Bile aids in the digestion and absorption of fats by breaking down them into smaller droplets, increasing their surface area for enzymes to act upon, and facilitating their breakdown and absorption in the small intestine.
- What is mastication? How does it help in the process of digestion?
Answer. Mastication is the process of chewing food in the mouth. It helps in the process of digestion by mechanically breaking down food into smaller particles, which increases its surface area and facilitates the action of enzymes in the digestive system. This makes it easier for enzymes to access and break down the food, aiding in the overall digestion and absorption of nutrients.
Question5. Answer the following question in 3-4 sentences.
- How is digestion in human beings different from that in grass-eating animals?
Animals.
Digestion in human beings differs from that in grass-eating animals primarily in the structure of the digestive system and the types of enzymes involved. Human beings have a relatively short digestive tract compared to grass-eating animals like cows, which have a complex stomach with multiple chambers for fermentation. Additionally, humans rely more on enzymatic breakdown of food in the stomach and small intestine, while grass-eating animals use fermentation in their specialized stomach compartments to break down cellulose from plant material into digestible nutrients like volatile fatty acids.
(b). What do the gastric juices secreted by the stomach contain? State their role in the chemical digestion of food.
Answer. The gastric juices secreted by the stomach primarily contain hydrochloric acid (HCl) and pepsin. Hydrochloric acid helps to maintain the acidic pH of the stomach, which is crucial for activating pepsinogen into its active form, pepsin. Pepsin then breaks down proteins into smaller peptides, helping their digestion. Additionally, the acidic environment created by gastric juices helps to kill bacteria and other pathogens present in food, aiding in food safety. These components work together to initiate the breakdown of ingested food, particularly proteins, into simpler molecules for absorption in the intestines.