Tag: biology

Questions Related to biology

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'.

Choose the correct answer from the alternatives given.
Carbon becomes available to crop plants in the form of:

c3, c4 and cam plants photosynthesis in higher plants biology

  1. elemental carbon

  2. carbonates

  3. carbon dioxide

  4. carbohydrates

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Correct Option: C
Explanation:

Plants use carbon dioxide during photosynthesis, the process whereby the plant converts the energy from the sun into a chemical carbohydrate molecule.

So the correct answer is "carbon dioxide".

Photosynthesis in C$ _4$ plants is relatively less limited by atmospheric C$O _2$ levels because 

c3, c4 and cam plants photosynthesis in higher plants biology

  1. effective pumping of CO2 into bundle sheath calls

  2. RuBisCo in C4 plants has higher affinity for CO2

  3. four carbon acids are the initial CO2 fixation products

  4. the primary fixation of CO2 is mediated via PEP carboxylase.

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Correct Option: D
Explanation:

Plants such as sugarcane and sorghum fix atmospheric carbon dioxide into phosphoenol pyruvic acid to produce oxaloacetic acid( a C$ _4$ acid) in the presence of phosphoenol pyruvate carbooxylase(PEP carboxylase). Such plants are called C$ _4$ plants.

In C$ _4$ plants, the primary product of OAA is mediated by PEP carboxylase, so it is relatively less limited by atmospheric CO$ _2$ levels.

So, the correct answer is 'The primary fixation of CO$ _2$ is mediated via PEP carboxylase'.

...............fixes carbon in green plants as simple sugars

c3, c4 and cam plants photosynthesis in higher plants biology

  1. Denitrification

  2. Photosynthesis

  3. Carbonation

  4. Bacteria.

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Correct Option: B
Explanation:

Photosynthesis is a process that converts $CO _2$ into organic compounds and starch (carbohydrate) using energy from sunlight. $O _2$ is also released during this process.

The saturation point of $CO _2$ in $C _4$ plants is?

c3, c4 and cam plants photosynthesis in higher plants biology

  1. $390$ $\mu l/L$

  2. $450$ $\mu l/L$

  3. $460$ $\mu l/L$

  4. $360$ $\mu l/L$

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Correct Option: D

Calculate the death rate if $6$ individuals in a lab population of $60$ fruit flies died during a particular week?

c3, c4 and cam plants photosynthesis in higher plants biology

  1. $0.2$

  2. $0.1$

  3. $1$

  4. $5$

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Correct Option: A

Freshwater protozoans react to a/an __________ environment by removing water through

basics of management of water environmental science conservation of resources food production: soil and water management biology

  1. hypotonic, turgor pressure

  2. isotonic, a contractile vacuole

  3. hypertonic, a contractile vacuole

  4. hypotonic, a contractile vacuole

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Correct Option: D