Tag: c3, c4 and cam plants

Questions Related to c3, c4 and cam plants

$C 3$ and $C _4$ and CAM plant species are found in _________.

c3, c4 and cam plants photosynthesis in higher plants biology

  1. Crassulaceae

  2. Cactaceae

  3. Euphorbiaceae

  4. Poaceae

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Correct Option: A

Reductional division involves _________________.

c3, c4 and cam plants photosynthesis in higher plants biology

  1. Separation of non-sister chromatins

  2. Reduction of chromosome number

  3. Separation of sister chromatics

  4. Crossing over

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Correct Option: A

The fixation of $CO 2$ to malate and its decarboxylation are conunon to both $C _4$ and  $CAM$ plants, but in $CAM$ plants these events _____________.

c3, c4 and cam plants photosynthesis in higher plants biology

  1. Are separated spatially

  2. Are separated temporally

  3. Require high light intensity

  4. Require high $CO _2$ concentration

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Correct Option: A

Choose the correct answers from the alternatives given.
Cyanobacteria, unlike other types of bacteria that photosynthesize, do:

c3, c4 and cam plants photosynthesis in higher plants biology

  1. not have a cell wall

  2. not have chlorophyll

  3. give off oxygen

  4. not give off oxygen

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Correct Option: C
Explanation:
Cyanobacteria, also called blue-green algae, were among the earliest organisms on Earth. These primitive bacteria produce oxygen during photosynthesis as they fix CO$ _2$ dissolved in the water. So the correct option is 'Give off oxygen’.

If 24G-3-P molecules are formed in ${ C } _{ 3 }$ plants.Calculate a) the number of $CO _{ 2 }$ used and b) the number of G3P used for regeneration RuBP molecules

c3, c4 and cam plants photosynthesis in higher plants biology

  1. $a=12, b=20$

  2. $a24, b=48$

  3. $a=12, b=24$

  4. $a=20, b=12$

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Correct Option: A
Explanation:

In carbon fixation 5 molecules of C)@ are combines or fixed with 6 molecules; Ribulose Bisphosphate(RuBP) to make 12 molecules of PGA.

The remaining 20 G3P molecules regenerate RuBP, which enables the system to prepare for the carbon fixation step.
So, the correct option is 'a = 12, b = 20'.

Kranz anatomy is not exhibited by which of the following plants?
c3, c4 and cam plants photosynthesis in higher plants biology

  1. Maize

  2. Sorghum

  3. Sugarcane

  4. Sunflower

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Correct Option: D
Explanation:

Kranz anatomy is observed in $C _4$ grasses like Maize, Sorghum and Sugarcane. This is to reduce the inefficiencies of RuBisCO that can catalyse the reaction with $O _2$ rather than $CO _2$ resulting in photorespiration than photosynthesis. To overcome this, $CO _2$ is first as a four carbon compound and then made available to RuBisCO, This is a spatial and temporal separation of reactions into bundle sheath cells and a ring of mesophyll cells surrounding the bundle sheath. Sunflower has only $C _3$ cycle of photosynthesis and does not exhibit Kranz anatomy.

So, the correct answer is 'Sunflower'


How many quanta are required to reduce one molecule of $CO _2$ and produce one molecule of $O _2$ in green plant photosynthesis?

c3, c4 and cam plants photosynthesis in higher plants biology

  1. 1

  2. 8

  3. 16

  4. 32

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Correct Option: A

In $C _4$ plants, agranal chloroplasts are found in?

c3, c4 and cam plants photosynthesis in higher plants biology

  1. Mesophyll cells

  2. Epidermal cell chloroplasts of green stem

  3. Bundle sheath cells

  4. Chloroplasts of guard cells

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Correct Option: C

The $C _4$ plants are photosynthetically more efficient than $C _3$ plants because.

c3, c4 and cam plants photosynthesis in higher plants biology

  1. The $CO _2$ compensation point is low

  2. $CO _2$ generated during photorespiration is trapped and recycled through PEP carboxylase

  3. The $CO _2$ efflux is not prevented

  4. They have more chloroplasts

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Correct Option: A
Explanation:

In C$ _3$ plants, three molecules of ribulose monophosphate (RuMP), 5C compound, are phosphorylated by ATP to form three molecules of ribulose bisphosphate (RuBP). RuBP is the first CO$ _2$ acceptor. It absorbs CO$ _2$ in presence of enzyme RuBP-carboxylase to form transitory or additive 6C compound, which is unstable. Three molecules of additive 6C compound immediately split up by hydrolysis into six molecules of 3C compound called 3-phosphoglyceric acid (3-PGA). C$ _3$ plants can do photosynthesis only at high concentrations of CO$ _2$. In  C$ _4$ plants, the CO$ _2$ is not directly absorbed by RuBP in presence of enzyme RuBP carboxylase as this enzyme helps to absorb CO$ _2$ having concentration of 50 ppm or more. However, C$ _4$ plants, due to high temperature and high light intensity, keep their stomata partially closed due to which the CO$ _2$ concentration goes down to 2 ppm. Hence the C$ _4$ plants can conduct photosynthesis at low concentrations of CO$ _2$.

So the correct option is 'the CO$ _2$ compensation point is low'.

State whether the following statements are true or false.
Oxygen liberation is absent in bacterial photosynthesis.

c3, c4 and cam plants photosynthesis in higher plants biology

  1. True

  2. False

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Correct Option: A
Explanation:

Oxygen liberation is absent in bacterial photosynthesis as they have pigment bacteriochlorophyll for photosynthesis and this pigment does not work in the presence of oxygen. Cyanobacteria are the only bacteria which performs oxygenic photosynthesis. 

So, the correct option is 'True'.