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

Plants get their energy from a process called...

  1. Osmosis

  2. Regeneration

  3. Photosynthesis

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

Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.

Multiple choice biology animal tissues, morphology and anatomy of cockroach specialized cells in animals tissues and types of tissues levels of organisation in animals

Unlike animals, plants get energy in the form of

  1. ATP

  2. Soil

  3. Roots

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

Chloroplasts contain a pigment called chlorophyll. Chlorophyll is able to capture the energy from the sun. In doing this, a series of chemical reactions occur that convert the sun's energy into ATP (energy for the plant). 

Therefore, the correct answer is option A.

Multiple choice botany photosynthesis electron transport system modern concept of photosynthesis photosynthesis in higher plants

Which statement is correct for given reaction for photosynthesis?
$2H _2A+CO _2\overset{light}{\rightarrow}2A+CH _2O+H _2O$.

  1. H donor is oxidisable substrate
  2. $O _2$ evolve from $H _2O$ if reducible compound is $H _2O$
  3. Glucose gain its oxygen from $H _2O$
  4. $(1)$ & $(3)$ both
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In the general equation of photosynthesis, H2A represents the hydrogen donor (like water or hydrogen sulfide), which is oxidized during the process.

Multiple choice botany photosynthesis electron transport system modern concept of photosynthesis photosynthesis in higher plants

Find out correct simplified equation of photosynthesis

  1. $\displaystyle CO _2 + 2H _2O \displaystyle

    \overset { light \, energy }{ \underset { chlorophyll }{ \longrightarrow } } C _5H _{10}O _4 + H _2O + O _2 \uparrow$
  2. $\displaystyle CO _2 + 2H _2O \overset { light \, energy }{ \underset { chlorophyll }{ \longrightarrow } } (CH _{2}O) _n + H _2O + O _2 \uparrow$
  3. $\displaystyle CO _2 + 2H _2O \overset { light \, energy }{ \underset { chlorophyll }{ \longrightarrow } } (CH _{2}O) _n + O _2 \uparrow$
  4. $\displaystyle CO _2 + 2H _2O \overset { light \, energy }{ \underset { chlorophyll }{ \longrightarrow } } C _3H _{6}O _3 + CO _2 + O _2 \uparrow$
  5. $\displaystyle CO _2 + 2H _2O \overset { light \, energy }{ \underset { chlorophyll }{ \longrightarrow } } C _6H _{12}O _6 + O _2 \uparrow$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The simplified equation for photosynthesis is CO2 + 2H2O -> (CH2O)n + H2O + O2, where (CH2O)n represents carbohydrates produced.

Multiple choice botany photosynthesis electron transport system modern concept of photosynthesis photosynthesis in higher plants

Splitting of water molecules during light reaction of photosynthesis is associated with
(a) PS I resulting in the release of $O _2$, protons and transfer of electrons to PS II (b) PS II resulting in release of $O _2$, protons and transfer of electrons to PS I (c) PS II resulting in release of $O _2$, protons and transfer of electrons to PS II (d) PS I resulting in the release of $O _2$, protons and transfer of electrons to PS I.
Of the above statements

  1. a alone is correct

  2. b alone is correct

  3. c alone is correct

  4. d alone is correct

  5. b and c are correct.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Photolysis of water occurs at the oxygen-evolving complex associated with Photosystem II, releasing protons and electrons which are then transferred to the electron transport chain.

Multiple choice botany photosynthesis electron transport system modern concept of photosynthesis photosynthesis in higher plants

The source of oxygen evolved during photosynthesis is

  1. $H _2O$
  2. $C _6 H _{12} O _6$
  3. $CO _2$
  4. $n(CH _2O)$.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
In the light reaction, the splitting of water occurs. The protons and oxygen formed by splitting of water are released within the lumen of the thylakoid. The oxygen produced is released as one of the net products of photosynthesis.
So, the correct option is 'H$ _2$O' 
Multiple choice botany photosynthesis electron transport system modern concept of photosynthesis photosynthesis in higher plants

During light reaction, as electrons move through photosystems, protons are transported across the membrane. This happens because of __________________.

  1. The primary acceptor of $e^-$(located towards the outer surface of the membrane) transfers its electron not to the $e^-$ carrier but to H carrier
  2. The primary acceptor of $e^-$ transfers only its $e^-$ to $e^-$ carrier.
  3. The primary acceptor of $e^-$ transfers only its $H^+$ to the nearest carrier.

  4. NADP - reductase is present in grana
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

As electrons move through the transport chain, protons are pumped into the thylakoid lumen because the primary electron acceptor transfers electrons to a hydrogen carrier, which then releases protons into the lumen.

Multiple choice botany photosynthesis electron transport system modern concept of photosynthesis photosynthesis in higher plants

Cyclic photophosphorylation takes place in the thylakoid which lacks:

  1. Electron transport system

  2. Enzyme FNR(ferredoxin NADP reductase )

  3. Lumen
  4. Photosystem with absorption peak $700nm$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cyclic Photophosphorylation is the process, in which systems (like prokaryotes), just accomplishes the ADP to ATP for immediate energy for the cells. This type of photophosphorylation usually occurs in the thylakoid membrane. So the correct option is ' Electron transport system'.

Multiple choice botany photosynthesis electron transport system modern concept of photosynthesis photosynthesis in higher plants

Consider the following events in the photochemical conversion of light energy into chemical energy by chlorophyll during photosynthesis.
a. Charge separation
b. Absorption of a quantum of energy
c. Ejection of electron
d. Transfer of light energy
The correct sequence of these events is?

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

The correct sequence is: 1. Absorption of light energy (2), 2. Transfer of light energy (4), 3. Charge separation (1), 4. Ejection of electron (3).

Multiple choice botany photosynthesis electron transport system modern concept of photosynthesis photosynthesis in higher plants
Which range of wavelength (in nm) is called photosynthetically active radiation (PAR)? 

  1. 100-390

  2. 390-430

  3. 400-700

  4. 760-10,000
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sunlight or solar radiations reaching the earth have wavelength between 300 nm (in the ultra volt rang) to 2600 nm (in the infa-red range). Part of the spectrum used in photosynthesis has a wavelength between 400-700 nm, it is called as photo synthetically active radiation (PAR). 

Multiple choice botany photosynthesis types of chlorophyll pigments photosynthetic pigments
Accessory photosynthetic pigments in most green plants are 
  1. Chlorophyll $a$
  2. Chlorophyll $b$

  3. Carotenoids and xanthophylls

  4. Both (b) and (c)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Chlorophyll a is found in almost all photosynthetic plants except bacteria it is called primary photosynthetic pigment because it performs primary reactions of photosynthesis which involve the conversion of light energy into chemical energy. other photosynthetic pigments like chlorophyll b, xanthophylls and carotenes are called accessory pigments. They absorb light energy of different wavelengths, broaden the spectrum of light absorption and hand over the energy to chlorophyll aq through electron spin resonance and also protect chlorophyll a from photo-oxidation.
So the correct option is 'both (b) and (c)'.
Multiple choice botany photosynthesis types of chlorophyll pigments photosynthetic pigments

The photosynthetic pigment found in red algae is 

  1. Phycocyanin

  2. Carotene

  3. Phycoerythrin

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

Red algae (Rhodophyta) derive their characteristic red color and light-harvesting capability primarily from the water-soluble accessory pigment phycoerythrin.