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प्रश्न
Answer the following in detail.
Explain the process of transpiration. Describe some factors that affect it.
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उत्तर
Large quantities of water are absorbed by plants for photosynthesis and other processes. Excess of water is lost in the form of water vapour through the stomata and lenticels from the aerial parts of the plant by transpiration. It helps plants to maintain the concentration of sap inside the plant body. If plants do not remove excess water through transpiration, the dilute sap will prevent further absorption of water and minerals from the soil.
Factors affecting the rate of transpiration are :
- Sunlight: Rate of transpiration is more during the day as stomata are open. Stomata remain closed at night and thus no transpiration takes at night.
- Temperature: Transpiration is more on hot days than on cold days.
- Wind: Blowing wind removes water vapour faster from the leaves and hence transpiration rate increases.
- Humidity: If the air is humid, the rate of transpiration is low.
In the rainy season, transpiration is less since humidity is more.
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संबंधित प्रश्न
The diagram given below shows a section of human kidney. Study the diagram carefully and answer the questions that follow :
(i) Label the parts numbered 1 to 4.
(ii) Why does part ‘2’ have a striped appearance?
(iii) What is the fluid that passes down part ‘4’? Name the main nitrogenous waste present in it.
(iv) Mention the structural and functional units of kidneys.
(v) Name the two major steps in the formation of the fluid mentioned in Q.5 (a) (iii).
The given diagram represents a nephron and its blood supply. Study the diagram and answer the following questions:
(i) Label parts 1, 2, 3 and 4.
(ii) State the reason for the high hydrostatic pressure in the glomerulus.
(iii) Name the blood vessel which contains the least amount of urea in this diagram.
(iv) Name the two main stages of urine formation.
(v) Name the part of the nephron which lies in the renal medulla.
Name the two parts of a plant through which its gaseous waste products are released into the air.
A dialysis machine contains long tubes coiled in a tank containing dialysing solution
Name the main waste which passes into the dialysing solution.
Draw a neat labelled diagram of the human excretory system.
In humans, urea is formed in
Define the following term:
Osmoregulation
The diagram below represents a mammalian kidney tubule (nephron) and its blood supply. Parts indicated by the guidelines 1 to 8 are as follows:
1. U-shaped loop of Henle
2. Proximal convoluted tubule with blood capillaries
3. Bowman’s capsule
4. Afferent arteriole from the renal artery
5. Glomerulus
6. Venule to the renal vein
7. Collecting tubule
8. Distal convoluted tubule with blood capillaries Study the diagram and answer the following questions in each case:
(i) Where does ultrafiltration take place?
(ii) Which structure contains the lowest concentration of urea?
(iii) Which structure contains the highest concentration of urea?
(iv) Which structure contains the lowest concentration of glucose?
(v) Where is the most water reabsorbed?
Choose the correct option.
Visceral layer : Podocytes :: PCT : ________.
When uric acid is produced in excess, it gets deposited in joints, resulting in ____________.
