Friday, June 13, 2014

Life Process CBSE Test Paper - 02 for class 10

Trend setter CBSE TEST PAPER-02
SCIENCE & TECHNOLOGY (Class-10) Chapter 6 : Life Process
1. Point out of differences between an artery and vein. (1 mark)
Ans: Any one:
Artery
1. Vessels which carry blood from the heart to various body parts
2. Arteries carry oxygenated blood from the heart except pulmonary artery
3. Arteries have thick elastic muscular walls
4. Valves are absent
5. Blood flows under high pressure
Vein
1. Vessels which carry blood from the various body parts to the heart
2. Veins carry deoxygenated blood from the various body parts except pulmonary vein
3. Veins have thin non elastic walls
4. Valves are present to prevent the backward flow of blood
5. Blood flows under low pressure

2. Write the two functions of kidneys. 

Ans.  Osmoregulation and excretion.

3. Name the largest artery in human body. (1 mark)

Ans: The largest artery in the human body is the aorta. It carries oxygenated blood to the whole body from the heart.

4. What is the difference between stroma and grana? (2 marks)
Ans:
Grana
Stroma
The stacks of thylakoids are called grana.
Grana are connected by intergrana or stroma thylakoids
Grana contribute to chloroplasts' large surface area to volume ratio.
It carries all the enzymes, e.g., RUBISCO, needed to carry out the "dark" reactions of photosynthesis

5. Write two differences between the transport of materials in xylem and phloem. (2 marks)
Ans: 
Xylem
Phloem
(i) Functional xylem ells are dead.
(i) Functional phloem cells are alive.
(ii) It carries mineral salts, water and traces of organic molecules
(ii) An organic solution of sugars and amino acids is
translocated.
(iii) The movement is only upward.
(iii) The movement can be upward or downward.

6. What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration? (2 marks)

Ans: In the aquatic habitat the concentration of oxygen is good up to a certain depth only. Moreover, as oxygen is available as dissolved in water, so taking oxygen from there is not a very efficient method to that.
In terrestrial habitat oxygen is available in free form so it is easier to absorb by organisms. This is more efficient so terrestrial organisms can facilitate better utilization of food by way of respiration.

7. Differentiate between osmoregulation and excretion?

Ans: Excretion is the elimination of metabolic waste  products from the body.
Osmoregulation is regulating osmotic pressure of the body fluids by controlling the amount of water and salts in the body

8. Name any two autotrophic plants which also show heterotrophic mode of nutrition. Why do they need to do so? (2 marks)

Ans: All green plants are autotrophic but some of them also show heterotrophic nutrition like Venus fly trap and pitcher plant as their nutritional requirement is not fulfilled by photosynthesis like nitrogen and phosphorus as in some areas, the soil is deficient in nitrogen.

9. Name 3 kinds of blood vessels of human circulatory system. Write function of each. (3 marks)
Ans:
Arteries
Veins   
Capillaries
1.
Carry Oxygen rich blood from heart to all parts of the body.

Carry carbon dioxide rich blood from all parts of the body back to the heart.

Capillaries act as a link between arteries and veins.

2.
Since blood flow is rapid and at high pressure they have thick elastic walls.

They have thin walls

Consists of just a single layer of endothelial cells. 
Water and other small-molecule substances can pass through this wall.

3.
Valves are absent.

Valves present to prevent back flow of blood.

No valves are found

10. Name the constituents of blood. Why are WBC called ‘soldiers of the body’? (3 marks)

Ans: The constituents of blood are
1. Red blood cells or RBCs (erythrocytes)
 2. White blood cells or WBCs (leucocytes)
 3. Blood platelets (thrombocytes)
WBC is called ‘soldiers of the body’ because
(a) White blood cells protect the body from infec on. If germs like bacteria or viruses enter the body, these cells surround the germs and destroy them by digesting.
 (b) They also produce an bodies (blood proteins) which kill the germs and foreign particles entering our body.

11. Explain the process by which inhalation occurs during breathing in human beings. (3 marks)

Ans: he process by which oxygen rich air is taken up through the nostril into the body is known as inhalation. During inhalation, the chest cavity increases in size due to the downward movement of the diaphragm (dome shaped muscular sheet that separates chest from abdomen). As a result air from outside rushes into the lungs to fill the extra space.

Exhalation is the process by which carbon dioxide rich air comes out of the body. It occurs when the diaphragm moves up and the chest cavity becomes narrower. This creates a pressure on the air inside the lungs. As a result the air comes out of the lungs to the atmosphere due to lack of space inside. Both the process of inhalation and exhalation is commonly known as breathing.

12. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning. (3 marks)
Ans:

Alveoli
Nephron
Structure 
Structure
(i) Alveoli are tiny balloon-like structures present inside the lungs.
(i) Nephrons are tubular structures present inside the kidneys.
(ii) The walls of the alveoli are one cell thick and it contains an extensive network of blood capillaries.
(ii) Nephrons are made of glomerulus, bowman’s capsule, and a long renal tube. It also contains a cluster of thin-walled capillaries.
Function
Function
(i) The exchange of O 2 and CO2 takes place between the blood of the capillaries that surround the alveoli and the gases present in the alveoli.
(i) The blood enters the kidneys through the renal artery which branches into many capillaries in the glomerulus. The water and solute are transferred to the nephron at Bowman’s capsule. Then the filtrate moves through the proximal tubule and then down into the loop of henle. From henle’s loop, filtrate passes into the distal tubule and then to the collecting duct. The collecting duct collects the urine from many nephrons and passes it to the ureter. During the flow of filtrate, some substances such as glucose, amino acids, and water are selectively re-absorbed.
(ii) Alveoli are the site of gaseous exchange.
(ii) Nephrons are the basic filtration unit.

13. Draw a diagram of human alimentary canal showing duodenum, small intestine, liver and pancreas. (3 marks)
OR
State the two vital function of the human kidney.
Name the procedure used in the working of artificial kidney. (3marks)
Ans: (a) Function of Kidneys:
  • Absorption of water and salt
  • Removal of waste materials like urea, ammonia etc from blood
  • Blood pressure control

  (b) Artificial kidney works on the principal of dialysis. It is also known as haemodialysis.
In hemodialysis, only a few drops of blood are allowed to flow, through a special filter that removes wastes and extra fluid. The detoxified blood is then returned to the body.
The special filter used in dialysis consists of a number of tubes with semi-permeable lining, suspended in a tank filled with the dialysis fluid.

14. What are the methods used by plants to get rid of excretory products? (5 marks)

Ans:
Plants get rid of carbon dioxide and oxygen through diffusion. Old branches and leaves are shed off when they become useless. Plants release some waste products through roots also. Some waste products are deposited near bark as raisins or gums.

15. (i) State two structural differences between an artery and a vein. (5 marks)
(ii) Name a non-nucleated cell present in human blood and state one functions of this cell.
Ans: RBC. Their chief function is to transport oxygen to different parts of the bod
(iii) Draw a labelled diagram of human heart.
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