Tag: phases of photosynthesis

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Multiple choice botany metabolism, cell respiration, and photosynthesis light dependent or hill reaction phases of photosynthesis emerson's experiments & hill's reaction

Light phase consists of

  1. Two photochemical reactions

  2. Two photosynthetic units

  3. Two chloroplast parts

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

Light phase is also known as a photochemical phase because it is a light dependent phase. During this phase, the formation of high-energy chemical intermediates ATP and NADPH$ _{2}$ takes place. ATP and NADPH$ _{2}$ are the assimilatory power of photosynthesis. Light phase also includes light absorption, water splitting and release of oxygen. Two photosynthetic units called Photosystem I and Photosystem II are also involved in light phase. Light phase consists of two photochemical reactions, i.e. non-cyclic photophosphorylation and cyclic photophosphorylation.

Non-cyclic phosphorylation involves both Photosystem I and Photosystem II. These two photosystems work in series, first PS II and then PS I. NADPH is synthesized by this kind of electron flow. 
Cyclic photophosphorylation is performed by photosystem I independently. It produces ATP only. It does not involve the formation of NADPH. 

Multiple choice botany metabolism, cell respiration, and photosynthesis light dependent or hill reaction phases of photosynthesis emerson's experiments & hill's reaction

Light reaction of photosynthesis occur in 

  1. Only absence of light

  2. Only presence of light

  3. Presence and absence of light

  4. Absence of light in maximum intensity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In photosynthesis, the light-dependent reactions take place on the thylakoid membranes. The light-independent reactions take place in the stroma. The thylakoid membrane contains some integral membrane protein complexes that catalyze the light reactions. There are four major protein complexes in the thylakoid membrane Photosystem II (PSII), Cytochrome b6f complex, Photosystem I (PSI), and ATP synthase. These four complexes work together to ultimately create the products ATP and NADPH.

So, the correct answer is option B.

Multiple choice botany metabolism, cell respiration, and photosynthesis light dependent or hill reaction phases of photosynthesis emerson's experiments & hill's reaction

The products of photochemical reaction are

  1. $O _2$, ATP and NADPH
  2. $O _2$

  3. ATP and NADPH

  4. Organic compounds especially carbohydrates.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Light reactions of photosynthesis which takes place in thylakoids membranes of chloroplast utilize sunlight and water to produce oxygen, ATP and NADPH.

The energy from the sun is converted to ATP and NADPH which is later utilised in the dark reaction to produce organic compound glucose, hence organic compound is a byproduct of the dark reaction.  
Therefore option A is the ans 

Multiple choice botany metabolism, cell respiration, and photosynthesis light dependent or hill reaction phases of photosynthesis emerson's experiments & hill's reaction

In photosynthesis light energy is utilized in 

  1. Converting ATP into ADP
  2. Changing CO$ _{2}$ into carbohydrate

  3. Converting ADP into ATP

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

Photosynthesis is a process in which phosphorylation occurs. Phosphorylation is a process in which phosphate group is added, and in the case of photosynthesis it happens in the presence of light, thus called as 'photophosphorylation'. ADP is converted to ATP, the energy currency as the main product of this process. In photosynthesis, cyclic and non-cyclic photophosphorylation takes place in the light phase and generate ATP and NADPH.

So, the correct answer is option C.

Multiple choice botany metabolism, cell respiration, and photosynthesis light dependent or hill reaction phases of photosynthesis emerson's experiments & hill's reaction

The phenomenon of re-irradiation of absorbed light is called

  1. Photoluminescence

  2. Chemiluminescence

  3. Phosphorescence

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

Photoluminescence is the phenomenon of light emission after absorption of photons in the form of electromagnetic radiation. Chemiluminescence is the phenomenon of emission of light from a chemical reaction. Phosphorescence is a type of photoluminescence which is related to fluorescence. It does not re-irradiate the absorbed light immediately like fluorescence. Fluorescence is the phenomenon of re-irradiation of light absorbed light or electromagnetic radiation.

Thus, the correct answer is option D.

Multiple choice botany metabolism, cell respiration, and photosynthesis light dependent or hill reaction phases of photosynthesis emerson's experiments & hill's reaction

Raw materials required for light reactions are

  1. ADP and $H _2O$
  2. ADP, $H _2O$ and NADP
  3. ADP and $NADPH _2$

  4. ATP and NADP.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A) ADP and ${ H } _{ 2 }O$ are required in addition to NADP.

B) ADP, ${ H } _{ 2 }O$ and NADP are the raw materials used to produce ATP and NADPH.
C) NADPH is a product of the light reaction.
D) ATP is a product of the light reaction.
So the correct answer is 'ADP, ${ H } _{ 2 }O$ and NADP'.

Multiple choice botany metabolism, cell respiration, and photosynthesis light dependent or hill reaction phases of photosynthesis emerson's experiments & hill's reaction

PS I and PS II occur over

  1. Grana of chloroplast

  2. Matrix of mitochondria

  3. Stroma of chloroplast

  4. Inner membrane of mitochondrion
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The process that converts light energy into chemical energy takes place in a multi-protein complex called a photosystem. Two types of photosystems are embedded in the thylakoid membrane:- photosystem II ( PSII) and photosystem I (PSI). Each photosystem plays a key role in capturing the energy from sunlight by exciting electrons. These energized electrons are transported by “energy carrier” molecules, which power the light-independent reactions.


So, the correct option is 'Option A'.

Multiple choice botany metabolism, cell respiration, and photosynthesis light dependent or hill reaction phases of photosynthesis emerson's experiments & hill's reaction

Excitation of chlorophyll by light is

  1. Exergonic reaction

  2. Anabolic reaction

  3. Photochemical reaction

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

The first and foremost step of photosynthesis is the excitation of chlorophyll molecule which occurs with the absorption of light. This reaction is photochemical reaction since involves light and results in chemical change by transfer of electrons. The pigments present in the photosystems absorb photon of light. The photons excite electrons in the chlorophyll which then move through the electron transport chain and results in the production of carbohydrates and energy packets NADPH, ATP with the release of oxygen.

Multiple choice botany metabolism, cell respiration, and photosynthesis light dependent or hill reaction phases of photosynthesis emerson's experiments & hill's reaction

Light reaction of photosynthesis is also called

  1. Calvin cycle

  2. Hill reaction

  3. TCA cycle

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

The Hill reaction implies that the light-dependent reaction of photosynthesis is a result of a series of redox reactions and a suitable terminal electron acceptor is required for that reaction to occur. Hence, solar energy is converted to chemical energy by the reduction of NADP to NADPH.


So, the correct option is 'Hill reaction'.