Multiple Choice QuestionsThe true statement about 'green-house effect' is that it is
caused only by CO2
caused by CO2, CFCs, CH4 and NO2 gases
caused by combination of many gases
none of the above
In C4 plants, CO, fixation is done by
mesophyll cells
guard cells
sclerenchyma
chlorenchyma and hypodermis
C4 plants have better productivity because
C4 plants absorb more light
C4 plants absorb more CO2
C4 plants lack photorespiration
all of these
C.
C4 plants lack photorespiration
Presence of photorespiration is considered as a wasteful and energy consuming process in crop plants which ultimately leads to reduction in final yield of crops. It is estimated that during C4 photosynthesis, upto 50% of the CO2 fixed may have to pass through photorespiratory process, thereby resulting in considerable decrease in photosynthetic productivity. In C4 plants, there is some loss of photosynthetic activity on account of photorespiration which is absent in C4 plants and hence they have better productivity.
Assertion: Photorespiration is a wasteful process where there is no synthesis of ATP energy.
Reason: RuBisCO is present in mesophyll cells of C4 plants hence they show more productivity.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
The 1st CO2 fixation product of C4 plant is
Oxaloacetic acid
ribulose biphosphate
phosphoenolpyruvate
phosphoglyceric acid.
Photosynthesis in C4 plants is relatively less limited by atmospheric CO2 levels because
there is effective pumping of CO2 into bundle sheath cells
RuBisCO in C4 plants has higher affinity for CO2
six carbon acids are the primary initial CO2 fixation products
the primary fixation of CO2 is mediated via PEP carboxylase.
The chemiosmotic coupling hypothesis of oxidative phosphorylation proposes that adenosine triphosphate (ATP) is formed because
a proton gradient forms across the inner mitochondrial membrane
there is a change in the permeability of the inner mitochondrial membrane towards adenosine diphosphate (ADP).
high energy bonds are formed in mitochondrial proteins
ADP is pumped out of the matrix into the intermembrane space
Carbon dioxide is necessary for photosynthesis. The chemical used to remove this gas most effectively from entering a control apparatus is
calcium oxide
distilled water
potassium hydroxide solution
sodium carbonate.
Assertion: In light reaction of photosynthesis, light is required for the functioning of PS I and PS II, and production of NADPH and ATP.
Reason: Dark reaction does not occur in light.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Assertion : CAM plants lack structural compartmentation of leaf as found in C4 plants.
Reason : Stomata of CAM plants are open during the day.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
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