Biology

Photosynthesis in Plants

1,492 Questions

Photosynthesis is the biological process by which plants convert light energy into chemical energy. This page contains practice questions covering essential topics like chlorophyll, light reactions, and the pathways specific to plants. This material is crucial for medical entrance exams and academic assessments.

Chlorophyll and pigmentsLight reactionsCalvin cycleCAM plantsElectron transportPhotosynthesis factors

Photosynthesis in Plants Questions

Multiple choice botany plant nutrition experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments various experiments on photosynthesis experiments on photosynthesis - gases

The chemical compound used in the experiment to show that oxygen is evolved during photosynthesis is

  1. KOH.

  2. NaOH.
  3. KHCO$ _{3}$.

  4. All of the above.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Potassium bicarbonate (KHCO3) is commonly used in photosynthesis experiments to provide a controlled source of carbon dioxide for aquatic plants. When the plant performs photosynthesis, the oxygen evolved can be collected and observed.

Multiple choice botany how plants grow experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments various experiments on photosynthesis experiments on photosynthesis - gases

Hydrilla leaf is used in an experiment to test that

  1. Chlorophyll is necessary for photosynthesis.

  2. Light is necessary for photosynthesis.
  3. CO$ _{2}$ is necessary for photosynthesis.

  4. Oxygen is evolved during photosynthesis.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

To test that oxygen is evolved during photosynthesis few fresh Hydrilla plants in a glass beaker filled with water. A pinch of KHCO$ _{3}$ is added to it. It is kept in sunlight. After some time some bubbles (oxygen) escapes from the plant. This proves that oxygen is produced during the photosynthesis. It is evolved during the light reaction of the photosynthesis.

So, the correct answer is option D.

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

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? 

  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
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

(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?

  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)
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

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

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Photosynthesis relies on the absorption of visible light by chlorophyll pigments. UV and X-ray radiations have much higher energy levels than visible light and are not effectively absorbed by chlorophyll to drive the photochemical reactions, often causing damage to biological molecules instead.

Multiple choice botany how plants grow experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments various experiments on photosynthesis experiments on photosynthesis - gases

Oxygen evolution takes place during photosynthesis in green plants but not in bacterial photosynthesis, because _________________.

  1. Bacteria are prokaryotic and green plants are eukaryotic

  2. Only photo system I is present in bacterial photosynthesis

  3. Bacterial cell wall composition is different from green plant cell wall
  4. Rate of $O _2$ consumption in bacteria is higher than that in green plants
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice botany how plants grow experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments various experiments on photosynthesis experiments on photosynthesis - gases
Ingenhousz in an experiment showed that in bright sunlight, small bubbles were formed around the green parts of the plant, while in the dark, they did not. He identified these bubbles to be of ____________.
  1. $CO _{2}$
  2. $H _{2} O $
  3. $O _{2} $
  4. $H _{2} $
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Jan Ingenhousz (1730-1799), in his experiment with an aquatic plant, showed that in bright sunlight, small bubbles were formed around the green parts while in the dark, no such bubbles formed. He found out these bubbles to be of oxygen. He thus, confirmed that purification of air or formation of dephlogiston is carried out by green plants only in presence of sunlight. 

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

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?

  1. Arnon

  2. Emerson

  3. Warburg

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

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

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.

  1. Sunlight

  2. Iodine

  3. Starch

  4. Darkness
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice biology cell structure plant and animal cell cell structure and micro-organisms organisation of the organism

Which is incorrect for chloroplast

  1. Presence in algae and plants
  2. Release $O _2$

  3. Occurs only in cells with aerobic respiration

  4. None
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chloroplasts are found in photosynthetic organisms and do not require aerobic respiration to function; they are the site of photosynthesis, which is independent of the cell's respiratory state.

Multiple choice biology cell structure plant and animal cell cell structure and micro-organisms organisation of the organism

Chloroplast contains maximum quantity of _________________.

  1. Pyruvic carboxylase

  2. Hexokinase

  3. RUDP caboxylase

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

Pyruvate carboxylase is a mitochodrial enzyme that catalyzes carboxylation of pyruvate into oxaloacetate. Hexokinase is an enzyme of glycolysis and is present in the cytoplasm. RUBP carboxylase catalyzes carboxylation of RuBP during photosynthetic carbon fixation. Chloroplasts is the site of photosynthesis and contain maximum quantity of RUBP carboxylase. The correct answer is C.

Multiple choice biology cell structure plant and animal cell cell structure and micro-organisms organisation of the organism

In a chloroplast, what is the ration of chl a : chl b and carotenes : xanthophylls respectively?

  1. 3 : 1 and 2 : 1

  2. 2 : 1 and 3 : 1

  3. 3 : 2 and 1 : 1

  4. 1 : 1 and 3 : 2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • A chloroplast is the site of photosynthesis, it contains all the pigments required for the process of photosynthesis. Pigments are of two types: Chlorophylls and Carotenoids.
  • Chlorophylls are the green photosynthetic pigments, they are of mainly five types - chlorophyll a, b, c, d, and e. The amount of chlorophyll b is one-fourth of the total chlorophyll content while chlorophyll a is the universal or primary photosynthetic pigment and present in abundance.
  • Carotenes are hydrocarbons, they may be yellow, brown or reddish pigments.
  • Xanthophylls are oxygen-containing carotenes, yellowish brown in color.
So, the correct option is '3: 1 and 2: 1'.