Photosynthesis in Higher Plants — Page 5 | NEET Biology

Q41

In Kranz anatomy, the bundle sheath cells have

A thin walls, many intercellular spaces and no chloroplasts

B thick walls, no intercellular spaces and large number of chloroplasts

C thin walls, no intercellular spaces and several chloroplasts

D thick walls, many intercellular spaces and few chloroplasts

Correct Answer

Option B

Solution

(b) Bundle sheath cells: thick walls, no intercellular spaces, numerous agranal chloroplasts.

Q42

CAM helps the plants in :

A conserving water

B secondary growth

C disease resistance

D reproduction

Correct Answer

Option A

Solution

(a) CAM plants open stomata at night, fixing CO2 as malic acid, to conserve water.

Q43

The correct sequence of cell organelles during photorespiration is :

A Chloroplast-Golgibodies-mitochondria

B Chloroplast-Rough Endoplasmic reticulum, Dictyosomes

C Chloroplast-peroxisome-mitochondria

D Chloroplast-vacuole-peroxisome

Correct Answer

Option C

Solution

(c) Photorespiration: Chloroplast → peroxisome → mitochondria.

Q44

Bundle sheath cells in C4 plants

A Are rich in RuBisCo

B Are rich in PEP carboxylase

C Lack RuBisCo

D Lack both RuBisCo and PEP carboxylase

Correct Answer

Option A

Solution

(a) Bundle sheath cells in C4 plants are rich in RuBisCO (Calvin cycle site).

Q45

A plant avoids photorespiratory losses, has improved water use efficiency, shows high rates of photosynthesis at high temperatures and has improved efficiency of nitrogen utilisation. In which physiological group would you assign this plant?

A C3

B C4

C CAM

D Nitrogen fixer

Correct Answer

Option B

Solution

(b) C4 plants lack photorespiration, have Kranz anatomy, and are adapted to hot dry conditions.

Q46

With reference to factors affecting the rate of photosynthesis, which of the following statements is not correct?

A Increasing atmospheric CO2 concentration up to 0.05% can enhance CO2 fixation rate

B C3 plants respond to higher temperatures with enhanced photosynthesis while C4 plants have much lower temperature optimum

C Tomato is a greenhouse crop which can be grown in CO2-enriched atmosphere for higher yield

D Light saturation for CO2 fixation occurs at 10% of full sunlight

Correct Answer

Option B

Solution

(b) C4 plants have higher temperature optimum (not lower); C3 plants show more photorespiration at high temperatures.

Q47

The oxygenation activity of RuBisCo enzyme in photorespiration leads to the formation of

A 1 molecule of 3-carbon compound

B 1 molecule of 6-carbon compound

C 1 molecule of 4-C compound and 1 molecule of 2-C compound

D 2 molecules of 3-carbon compound

Correct Answer

Option A

Solution

(a) Oxygenation of RuBP by RuBisCo yields one 3-C (PGA) and one 2-C (phosphoglycolate).

Q48

Which fractions of the visible spectrum are primarily absorbed by carotenoids?

A Violet and blue

B Blue and green

C Green and red

D Red and violet

Correct Answer

Option A

Solution

(a) Carotenoids absorb mainly in the violet-blue range (400-480 nm).

Q49

Plants adapted to low light intensity have

A larger photosynthetic unit size than the sun plants

B higher rate of CO2 fixation than the sun plants

C more extended root system

D leaves modified to spines

Correct Answer

Option A

Solution

(a) Shade plants have larger photosynthetic units to capture more low-intensity light.

Q50

Photosystem II occurs in

A Stroma

B Cytochrome

C Grana

D Mitochondrial surface

Correct Answer

Option C

Solution

(c) PS II is located in the appressed thylakoid membranes of the grana.