Biology

Photosynthesis in Plants

1,508 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 hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

Production of $NADPH _2$ is not linked with ATP generation in

  1. Photorespiration

  2. Light recation

  3. Hexose monophosphate pathway

  4. Dark reaction
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Hexose monophosphate pathway (HMP) or pentose phosphate shunt is an alternate glucose metabolism that occurs in adipose tissues, liver, erythrocytes, testes, adrenal glands, mammary glads etc. This pathway is performed to generate the $NADPH _2$ to facilitate the cholesterol synthesis, steroid and lipid production and fatty acid synthesis. Thus signifying that HMP pathway readily takes place in tissues associated with lipogenesis like liver and adipose tissue. It is not linked with ATP generation. Also, the ribose sugars generated are used in DNA and RNA and many nucleotides like $ATP$, $FADH _2$ $CoA$ etc.

Photorespiration, light reaction and dark reaction are associated with phosphorylation.
Hence, the correct answer is 'Hexose monophosphate pathway'

Multiple choice bio-chemistry respiration in organisms glucose metabolism the need for energy in living organism respiratory function

In which of the following steps dehydrogenate occurs? 

  1. glucose $\rightarrow$ glucose 6-phosphate
  2. 3 - PGA $\rightarrow$ 2 - PGA
  3. PEPA $\rightarrow$pyruvate
  4. PGAL $\rightarrow$ 1, 3diPGA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The G6PDwhich is glucose dehydrogenate gene provides instructions for making an enzyme called glucose-6-phosphate dehydrogenase. This enzyme, which is active in virtually all types of cells, is involved in the normal processing of carbohydrates. This enzyme helps protect red blood cells from damage and premature destruction.
So, the correct answer is glucose $\rightarrow$ glucose 6-phosphate

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
Which of the following scientists concluded by his experiments that green plant play a role in  purifying the noxious air only in the presence of sunlight?

  1. Priestley

  2. Ingenhousz

  3. Sachs

  4. Engelmann
Reveal answer Fill a bubble to check yourself
B 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 different types of nutrition in plants experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

The leaf is boiled in alcohol for a few minutes using water bath, it is essential because

  1. Alcohol is highly volatile

  2. Alcohol dissolves the chlorophyll and decolourises the leaf.

  3. Alcohol cleans the leaf

  4. Alcohol gives the nutrients to the leaf
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Boiling a leaf in alcohol is a standard procedure in photosynthesis experiments to extract chlorophyll, which allows for the subsequent detection of starch using iodine solution.

Multiple choice biology different types of nutrition in plants experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

Consider the following pigments.
a. Carotenoids
b. Chlorophyll
c. Phycoerythrin
d. Phycocyanin
e. Phytochrome
The most likely sequence of the order in which they appeared during the process of evolution is?

  1. $1, 2, 3, 4, 5$
  2. $1, 2, 4, 3, 5$
  3. $1, 4, 3, 5, 2$
  4. $1, 4, 2, 3, 5$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The evolutionary sequence of pigments is generally accepted as starting from simpler light-harvesting molecules like carotenoids, followed by chlorophyll, then phycobilins (phycoerythrin/phycocyanin), and finally regulatory pigments like phytochrome.

Multiple choice biology plant nutrition experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

When the rate of translocation is slow, the rate of photosynthesis shall:

  1. Decrease

  2. Increase

  3. Remain unchanged

  4. Become zero
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Water in the plant is transported using a pressure flow mechanism. Translocation is the transport of nutrients and carbohydrates from source to sink, which is performed by the phloem. Pholem and xylem are present adjacent to each other in the vascular bundle of the plant. When the sugar ie sucrose is produced in the mesophyll of the leaves is produced it is transferred to the phloem to be transported. As the sugar concentration in the phloem increases water is diffused in the phloem from the xylem and this is what we call ascent of sap. When the water is diffused in the cells due the rigid wall the pressure in the cell increases. due to increase in the pressure at the source and low pressure at the sink the water along with the sugar is transported. As the sugar reaches the sink and leaves the cell water also moves out of the cell. Therefore the rate of photosynthesis is dependent on translocation rate. As the rate of translocation decreases the rate of photosynthesis also decreases.

  • Therefore, option A is correct. 
Multiple choice biology photosynthesis and respiration experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

Which of the following is the least effective in photosynthesis?

  1. Red light

  2. Blue light

  3. Green light

  4. Violet
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Green is the least effective color of light in driving photosynthesis. Photosynthesis occurs in plants and algae using chlorophyll, and because chlorophyll reflects rather than absorbs green light, green light cannot be used in the photosynthetic process.
So, the correct answer is option C.
Multiple choice biology photosynthesis and respiration experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

The pigment that absorbs red and far red light in plant is 

  1. Cytochrome.

  2. Xanthophyll.

  3. Phytochrome.

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

Phytochrome is a photoreceptor, a pigment that plants, and some bacteria and fungi, use to detect light. It is sensitive to light in the red and far-red region of the visible spectrum. Many flowering plants use it to regulate the time of flowering based on the length of day and night (photoperiodism) and to set circadian rhythms. It also regulates other responses including the germination of seeds, elongation of seedlings, the size, shape, and number of leaves, the synthesis of chlorophyll, and the straightening of the epicotyl or hypocotyl hook of dicot seedlings. 

So, the correct answer is option C.

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

During photosynthesis, oxygen in glucose comes from

  1. oxygen in air

  2. water

  3. carbon dioxide

  4. both (B) and (C).
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Isotope labeling experiments (using O-18) have demonstrated that the oxygen released during photosynthesis comes from the splitting of water molecules (photolysis), not from carbon dioxide.

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

It is advantageous to use a water plant to demonstrate photosynthesis other than a land plant because

  1. It photosynthesize rapidly

  2. It respires slowly

  3. It does not transpire
  4. O$ _2$ bubbles from cut water plant can be collected over H$ _2 $O
Reveal answer Fill a bubble to check yourself
C Correct answer
Multiple choice biology photosynthesis and respiration experiments on photosynthesis - light importance of light for photosynthesis photosynthesis necessities- experiments

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

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

The term dark reaction for the biosynthetic phase of photosynthesis is a misnomer because these reactions do not actually require darkness or occur exclusively at night. Instead, they can and do occur during the day, relying on the ATP and NADPH produced during the light-dependent reactions.

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.