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Question
Two groups (A & B) of bean plants of similar size and same leaf area were placed in identical conditions. Group A was exposed to the light of wavelength 400-450 nm & Group B to light of wavelength of 500-550 nm. Compare the photosynthetic rate of the 2 groups giving reasons.
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Solution
‘A’ group of plants exposed to light of 400 - 450nm. Chlorophyll a shows maximum absorption peak at 450nm (blue region). Hence rate of photosynthesis was high.
‘B’ group of plants exposed to light of 500 - 550nm. This wavelength refers to green region of the spectrum. Chlorophyll does not absorb light in the green region but reflects green. So plants appear green rate of photosynthesis was negligible in these plants.
RELATED QUESTIONS
Short answer question.
Why do leaves generally look green?
Short answer question.
Which four of the following are needed for photosynthesis in a leaf:
(i) Carbon dioxide:
(ii) Oxygen:
(iii) Nitrates :
(iv) Water:
(v) Chlorophyll:
(vi) Soil:
(vii) Light:
Suppose we compare the leaf with a factory, match the items in Column A with those in Column B.
| Column A | Column B | ||
| Left | Factory | ||
| 1 | Cells in the leaf | a | Raw materials |
| 2 | Chloroplast | b | Power |
| 3 | Sunlight | c | Machinery |
| 4 | Oxygen and water | d | End product |
| 5 | Carbon dioxide and water | e | By product |
| 6 | Glucose | f | Workroom |
State whether the following statement is True or False:
Green plants prepare their food by using two raw materials, oxygen and water.
State whether the following statement is True or False:
The chlorophyll enables the plants to use light energy.
State whether the following statement is True or False:
Photosynthesis occurs only in chlorophyll-containing parts of the plant.
Long answer question.
Do plants need oxygen? If so, what is its source?
Answer the following in one word.
Which organ is called the voice box?
Tick the most appropriate answer.
Exhaled air contains
Identify the false statement and rewrite it correctly by changing the first or last word only.
Photosynthesis requires enzymes.
Identify true statement regarding light reaction of photosynthesis.
When there is plenty of light and a higher concentration of O2, what kind of pathway does the plant undergo? Analyse the reasons.
Process of photosynthesis is ______.
Photorespiration is favoured by :
Why does the rate of photosynthesis decrease at higher temperatures?
The figure shows the effect of light on the rate of photosynthesis. Based on the graph, answer the following question:
- At which point/s (A, B or C) in the curve is light a limiting factor?
- What could be the limiting factor/s in Region A?
- What do C and D represent on the curve?
Graph of light intensity on the rate of photosynthesis
The optimum temperature for the process of photosynthesis is ______.
