C4 pathway is advantageous over C3 pathway in plants as it from

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 Multiple Choice QuestionsMultiple Choice Questions

231.

Chlorophyll molecules are located in the

  • thylakoid membrane

  • thylakoid lumen

  • stroma

  • inner chloroplast membrane


232.

The correct sequence of organelles in which glycolate and glyoxylate are produced sequentially in photorespiration is

  • chloroplast and mitochondria

  • chloroplast and peroxisome

  • peroxisome and mitochondria

  • peroxisome and chloroplast


233.

Identify the correct statements in relation to C4 photosynthesis.

  • Kranz anatomy is an essential feature for C4 plants

  • C4 plants have higher water use efficiency than C3 plants

  • Photorespiration can be minimised when C3 pathway is in operation

  • Conversion of oxaloacetate to malate occurs in the bundle sheath cells


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234.

C4 pathway is advantageous over C3 pathway in plants as it

  • occurs in relatively low CO2 concentration

  • uses more amount of water

  • occurs in relatively low O2 concentration

  • is less efficient in energy utilisation


A.

occurs in relatively low CO2 concentration

Plants with the C4 pathway has many advantages over a plant with a C3 pathway. When the weather is hot, acid, dry, the leaves close their stomata to eliminate water less whereas in C3 plants this closure results in low carbon dioxide concentrations and ultimately both loss of RuBP and inhibition of the Calvin-Benson cycle by photorespiration.

There are no such disadvantages in a C4 plant during hot, dry weather. Even with its stomata are closed, carbon dioxide is fixed because of the efficiency of REP carboxylase in trapping and concentrating carbon dioxide. Consequently, the Calvin-Benson cycle continues to produce glucose and there is no loss of chemical energy through photorespiration.


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235.

Opening and closing of stomata is controlled by

  • abscisic acid

  • CO2 concentration

  • O2 concentration

  • light intensity


236.

As compared to sun plants, the plants, which are adopted to low light intensity possess

  • more extended root system

  • very high rate of CO2 fixation

  • larger photosynthetic units

  • more extended shoot system


237.

How many pigment molecules constitute a single photosystem?

  • 2500

  • 250-400

  • 2000

  • 2


238.

Oxygen released in photosynthesis comes outby

  • photophosphorylation

  • photolysis of water

  • photorespiration

  • Kelvin cycle


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239.

Glycolate accumulates in chloroplast there is

  • low CO2

  • high CO2

  • bright light

  • low temperature


240.

Which of the following inhibits O2 release in light phase?

  • Zeatin

  • PMA

  • DCMU

  • None of these


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