Tag: biology

Questions Related to biology

Word dark reaction for biosynthetic phase of photosynthesis is misnomer word because ___________________.

biology photosynthesis and respiration experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

  1. Dark reaction occur during dark

  2. Dark reaction occur during day

  3. Dark reaction is completely free from light

  4. Dark reaction occur during short dark intervals

Show answer
Correct Option: A

A green plant bends towards the source of light when exposed to the light on only one side, it bends towards the source of light as it grows. Which of the following is the best explanation of the phenomenon 

biology photosynthesis and respiration experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

  1. The apices of their stems are attracted by light

  2. They need light for photosynthesis

  3. Some auxins accumulates on the shaded side to induce greater cell elongation on that side

  4. Light stimulates the cells on the illuminated side to increase in length

Show answer
Correct Option: C
Explanation:

Accumulation of auxin as the apex of the plant, which is responsible for the phototropism movement so that plant cells are elongated.

So the correct option is C.

Two green plants are kept separately in oxygen free containers, one in the dark and the other in continuous light. Which one will live longer? 

biology photosynthesis and respiration experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

  1. The plant kept in dark

  2. The plant kept in light

  3. Both the plants will live for the same time

  4. None of the above

Show answer
Correct Option: B
Explanation:

The plant kept in continuous light will live longer, because it will be able to produce oxygen required for its respiration by the process of photosynthesis.

Oxygen is evolved as a by-product of photosynthesis during photolysis of water.
So, the correct answer is option B.

(i) Pluck the leaf to be experimented
(ii) Cover a portion of leaf on both sides by using strips of black paper
(iii) Keep the plant in dark place for three days to destarch its leaves.
(iv) Test the experimental leaf the the presence of starch 
(v) Expose the plant to sunlight for four hours 
(vi) Remove the black paper strip from the leaf

Given in the box are steps written randomly for the experiment to show that light is essential for photosynthesis. Which of the following sequences of steps is to be followed by the successful run of the experiment?

biology photosynthesis and respiration experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

  1. (i), (iii), (ii) (iv), (v), (vi)

  2. (ii), (i), (v), (vi), (iii), (iv)

  3. (iii), (ii), (v), (i), (vi), (iv)

  4. (v), (ii), (i), (iii), (iv), (vi)

Show answer
Correct Option: C
Explanation:

The starch in the leaves is eliminated by keeping the plant in a dark place for 3 days. A leaf is selected and covered with a black strip on both sides. The plant is kept in sunlight for 4 hours. The experimental leaf is plucked and the strip is removed from it to perform the starch test. It is found that he leaf covered with black paper will turn brown and the part of the exposed leaf will turn blue-black. This result proves that starch is formed in the leaf where sunlight is available and is not formed in absence sunlight. Thus the correct answer is option  C.

UV or X-ray radiation is NOT suitable for photosynthesis is green plants because such a radiation.

biology photosynthesis and respiration experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

  1. Is not visible

  2. Is not absorbed by chlorophyll

  3. Causes ionization of chlorophyll

  4. Leads to an increase in rotational and vibration energy of chlorophyll

Show answer
Correct Option: A

Who observed that when chlorella cells are exposed to continuous light, the rate of  photosynthesis was less as compared to those exposed in intermittent light?

biology photosynthesis and respiration experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

  1. Arnon

  2. Emerson

  3. Warburg

  4. Ruben

Show answer
Correct Option: B
Explanation:

  • Warburg discovered that a decrease in photosynthesis by increasing the oxygen concentration. Oxygen is the competitive inhibitor of the carbon dioxide fixation by RuBisCo, which initiates photosynthesis. Furthermore, oxygen stimulates photorespiration which reduces photosynthetic output. These two mechanisms working together are responsible for the Warburg effect. So, this option is incorrect.
  • Arnon discovered the photosynthetic phosphorylation. So, this option is incorrect.
  • Samuel Ruben discovered that oxygen, which is released during photosynthesis came from a water molecule. So, this option is incorrect.
  • Emerson observed that when Chlorella cells are exposed to continuous light, the rate of photosynthesis was less as compared to those exposed to the intermittent light. 

So, the correct answer is option B.

What screens out 99% of harmful rays of sunlight?

biology photosynthesis and respiration experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

  1. $CO$

  2. $CO _{2}$

  3. $O _{3}$

  4. $O _{2}$

Show answer
Correct Option: C

A plant was kept in a dark room for a week. When its leaves are tested with iodine solution, it did not show the presence of starch. From this experiment we can conclude that _____ is required for photosynthesis.

biology photosynthesis and respiration experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

  1. Sunlight

  2. Iodine

  3. Starch

  4. Darkness

Show answer
Correct Option: A
Explanation:

Sunlight is essential for photosynthesis as the plant is kept in dark room for a week there is a lack of sunlight hence photosynthesis has not taken place.

In aeroponics, which one of the following absorbs required nutrients to the plant?

biology mineral nutrition in plants hydroponics hydroculture essential and non-essential mineral elements

  1. Roots

  2. Stem

  3. Leaves

  4. External factors

Show answer
Correct Option: A
Explanation:
Aeroponics is the process of growing plants in an air or mist environment without the use of soil or an aggregate medium. In aeroponics, growing plants are suspended in a closed or semi-closed environment by spraying the plant's roots with an atomized or sprayed, nutrient-rich water solution. 
So the correct option is "roots". 

Which of the following technique/s of agriculture is gaining significance in developing space foods?

biology mineral nutrition in plants hydroponics hydroculture essential and non-essential mineral elements

  1. Aeroponics

  2. Hydroponics

  3. Somatic hybridization

  4. Both A and B

Show answer
Correct Option: D
Explanation:

 A.Aeroponics is growing a plant in air or mist environment.This technique is gaining significance in developing space foods because it do not require soil to grow the plant.

 B.hydroponic is growing plant in nutrient-enriched water without soil. This technique is gaining significance in developing space foods because it do not require soil to grow the plant.
C.Somatic hybridization - Fusion of protoplasts of two different plants.
So the correct option is "both A and B".