Tag: importance of light for photosynthesis

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Multiple choice biology nutrition and respiration importance of light for photosynthesis various experiments on photosynthesis experiments on photosynthesis - gases

A student sets up the apparatus for the experiment to show that $CO _{2}$ is released during
respiration. After two hours he would observe :

  1. KOH turning milky

  2. water level rising in the bent tube in the beaker.

  3. water level decreasing in the bent tube

  4. no change in water level in the bent tube.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

As the germinating seeds respire, they consume oxygen. The KOH pellets absorb the CO2 released. This consumption of gas inside the airtight flask creates a pressure drop, causing the water level in the bent tube to rise.

Multiple choice biology nutrition and respiration importance of light for photosynthesis various experiments on photosynthesis experiments on photosynthesis - gases

What happens if the process of photosynthesis in plants for the formation of carbohydrate ?

  1. Reduction of $O _2$
  2. Reduction of $N _2$
  3. Reduction of $CO _2$
  4. Oxidation of $H _@$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Formation of glucose by the unitlization of 6 molecules of carbon dioxide and 12 molecules of water in presence of sunlight in chloroplast is called Photosynthesis. In this process Water is oxidized (loses electrons) in  and carbon dioxide is reduced(gains electrons).
So, the correct option is 'Reduction of CO2'.
Multiple choice biology nutrition and respiration importance of light for photosynthesis various experiments on photosynthesis experiments on photosynthesis - gases

In the experiment to show that $CO _{2}$, is given out during respiration the chemical filled in the small test tube is :

  1. alcohol

  2. KOH

  3. lime water

  4. iodine solution
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

KOH (potassium hydroxide) is used in the experiment because it effectively absorbs carbon dioxide gas, which allows the student to observe the change in pressure.

Multiple choice biology nutrition and respiration importance of light for photosynthesis various experiments on photosynthesis experiments on photosynthesis - gases

Moll's half experiment is performed to show that

  1. Light is needed for photosynthesis.

  2. Chlorophyll is needed for photosynthesis.

  3. Oxygen is evolved during photosynthesis.
  4. CO$ _{2}$ is needed for photosynthesis.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

CO$ _{2}$ is needed for photosynthesis is shown by Moll's half leaf experiment. In this experiment, only that part of the leaf will show blue color which was present outside the bottle because they are able to take carbon dioxide from the stomata of the leaf.

So, the correct answer is option D.

Multiple choice biology nutrition and respiration importance of light for photosynthesis various experiments on photosynthesis experiments on photosynthesis - gases

In Moll's half leaf experiment, only that part of leaf will show blue colour which was ........... the bottle.

  1. Inside

  2. Outside

  3. Whole leaf shows blue coloration

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In Moll's half-leaf experiment, the part of the leaf inside the bottle is deprived of CO2, preventing photosynthesis. The part outside has access to CO2, allowing photosynthesis to occur and starch to be produced, which turns blue with iodine.

Multiple choice biology nutrition and respiration importance of light for photosynthesis various experiments on photosynthesis experiments on photosynthesis - gases

Path of carbon in photosynthesis was found by using 

  1. Centrifugation

  2. Radio isotopes

  3. Fractionation

  4. Chromatography
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Calvin cycle is used for the fixation of carbon dioxide to produce glucose. Radioactive isotopes of carbon (C-14) and phosphorus (P-32) was used to trace the path for the carbon assimilation. A photosynthesizing plant does not strongly discriminate between the most abundant natural carbon isotope C-12 and C-14. During photosynthesis in the presence of 14$CO _2$, the compounds formed become labeled with the radioisotope.

So, the correct answer is option B.

Multiple choice biology nutrition and respiration importance of light for photosynthesis various experiments on photosynthesis experiments on photosynthesis - gases

Given below are assertions and reasons. Point out if both are true with reason being correct explanation (A), both true but reason is not correct explanation (B), assertion true but reason is wrong (C), both are wrong (D).
Assertion. Under conditions of high intensity and limited $CO _2$ supply, photorespiration has a useful role in protecting the plants from photo-oxidative damage.
Reason. If enough $CO _2$ is not available to utilise light energy for carboxylation to proceed, the excess energy may not cause damage to plants

  1. A

  2. B

  3. C

  4. D
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The assertion is true because photorespiration dissipates excess light energy when CO2 is limiting, preventing photo-oxidative damage. The reason is false because if CO2 is not available for carboxylation, the excess energy is precisely what causes damage, which photorespiration helps mitigate.