Tag: botany

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Questions Related to botany

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 results in products like

  1. Starch and O$ _2$.
  2. ADP, NADPH + H$^+$ and electrons.
  3. ATP, NADPH + H$^+$ and O$ _2$.
  4. Glucose and O$ _2$.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The light reaction takes place in the grana of the chloroplast. This is also known as the cyclic and non-cyclic form of photophosphorylation in which the ATP and NADPH + H$^+$ are produced. In the non-cyclic photophosphorylation, there is splitting of the water molecules which results in the production of oxygen molecule. 

Thus, 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

ATP formation during photosynthesis is known as

  1. Phosphorylation.

  2. Photophosphorylation.

  3. Oxidative phosphorylation.

  4. Substrate level phosphorylation.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Photophosphorylation refers to the use of light energy from photosynthesis to ultimately provide the energy to convert ADP to ATP, thus replenishing the universal energy currency in living things. Light generally provides energy to form the bonds. It is an endothermic reaction.

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

What percentage of usable radiant energy entering a reaction site of photosynthesis is converted to potential energy _________.

  1. 10%

  2. 20%

  3. 35%

  4. 42%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In photosynthesis, only a small fraction of the total incident solar energy is converted into chemical energy. Scientific literature typically cites values in the range of 1% to 5% for overall efficiency, but specific textbook contexts sometimes use 35% as a theoretical maximum for specific wavelengths or specific reaction steps.

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

In light phase of photosynthesis there is formation of

  1. $ATP$
  2. $NADPH _2$
  3. Both $ATP$ and $NADPH _2$

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

In light-dependent reactions, the energy from sunlight is absorbed by chlorophyll and converted into chemical energy in the form of electron carrier molecules like ATP and NADPH.

Light energy is harnessed in Photosystems I and II, both of which are present in the thylakoid membranes of chloroplasts.
Just as the name implies, light-dependent reactions require sunlight. In the light-dependent reactions, energy from sunlight is absorbed by chlorophyll and converted into stored chemical energy, in the form of the electron carrier molecule NADPH (nicotinamide adenine dinucleotide phosphate) and the energy currency molecule ATP (adenosine triphosphate). The light-dependent reactions take place in the thylakoid membranes in the granum (stack of thylakoids), within the chloroplast.

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'.