Time: 1 hr
Marks: 30
Section-A Choose the Correct Option 5 x 1=5
1. The inner lining of the stomach is protected from hydrochloric acid by which of the following.
a. Salivary amylase
b. Pepsin
c. Mucus
d. Bile
2. In which medium Pepsin is active
a. basic
b. acidic
c. neutral
d. sometimes acidic and sometimes basic
3. Enzyme pepsin helps in the digestion of
a. starch in mouth
b. protein in stomach
c. fat in stomach
d. protein in pancreas
4. The small intestine receives the digestive enzymes from
a. Mouth and Stomach
b. Stomach and liver
c. Liver and Pancreas
d. All the above
5. Assertion (A): Digestion breaks down large complex molecules into easily absorbable simple smaller molecules.
Reason (R): Digestion is necessary for the absorption of molecules.
a. (A) and (R) are correct and (R) is the correct explanation of (A)
b. (A) and (R) are correct but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true
Section-B Very Short Answer Questions 3 x 2=6
6. What will happen if we kill all the organisms of one trophic level?
7. What happens if the system of blood vessels develops a leak?
8. Name the blood vessel that brings oxygenated blood to the human heart. Which chamber receives oxygenated blood?
Section C- Short Answer Questions 3 x 3 = 9
9. Answer the following.
- a. Name the basic filtration unit of kidneys.
- b. Name the substances that are reabsorbed from the initial filtrate in the tubular part of this filtration unit
- c. Under what conditions are hemodialysis (artificial kidney) carried out in a person?
10. During respiration pyruvic acid is formed from glucose. State the end products formed from it on the further breakdown in each of the following cases.
- i) In the absence of oxygen in yeast.
- ii) Lack of oxygen in muscles
- iii) In the presence of oxygen in mitochondria
11. List three characteristics of the lungs that make it an efficient respiratory surface.
Section D- Short Answer Questions 2 x 5 = 10
11. Discuss the mechanism of respiration in humans. 12. How is the structure of leaves suited to its function?
