Tag: light dependent or hill reaction

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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

First reaction in photosynthesis is

  1. Photolysis of water

  2. Excitation of chlorophyll molecules

  3. Formation of ATP
  4. Fixation of CO$ _2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

During the first stage of photosynthesis, called the light-dependent reaction, sunlight excites the electrons in the chlorophyll pigment. The organism uses this energy to create the energy carrier molecules ATP and NADPH, which are crucial for carbon fixing during the second stage.


So, the correct option is 'Excitation of chlorophyll molecules'.

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

How much oxygen is formed from 264 g of $CO _2$ and 216 g of $H _2O$?

  1. 96 g

  2. 216 g

  3. 264 g

  4. 192 g.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

  • Moles = Weight in gms/molecular weight
So, moles of CO$ _2$ =264/44 = 6 moles.
  • In same way moles of H2O = 216/18 = 12 moles.
In a reaction of photosynthesis, 6 moles of CO$ _2$ and 6 moles of water lead to the production of 6 moles of oxygen. Here, CO$ _2$ is a limiting reactant. So only 6 moles of oxygen will be formed.So, 6 moles of O$ _2$ = weight in gms/32 (molecular weight of O$ _2$). Weight in gms = 6 x 32 = 192 gms.

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

Fluoroscence differs from phosphorescence in being

  1. Delayed emission

  2. Instant emission

  3. Bioluminescence

  4. Chemiluminescence
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Fluorescence is the phenomenon of absorption of energy by molecule or atom and instant emission of a photon of light or electromagnetic radiation after being excited to a higher quantum state. In this, time interval between absorption and emission of energy is very short. Unlike fluorescence, phosphorescence does not show instant emission of radiation. In this, excitation of electrons is accompanied with the change of a spin state. In this, the time interval between absorption and emission of energy is comparatively longer.
Thus, 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

In plants, food formation during photosynthesis takes place

  1. In root

  2. In leaf

  3. In stem

  4. In flower
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Photosynthesis is the process by which plant utilizes the energy obtained from sunlight to produce glucose from carbon dioxide and water. During this process, oxygen is released as the by product. It takes place in leaf cells. Leaf cells contain chloroplasts. The chloroplasts contain green pigment chlorophyll which prepares the food during photosynthesis.

Thus, the correct answer is 'In leaf'.

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

Red drop and Emerson effect have proved the existence of ______________.

  1. Light and dark reactions is photosynthesis

  2. Two distinct photo systems is photosynthesis

  3. The supply of electrons from oxygen evolving complex
  4. Electron transport from water to NDAP$+$ across thylakoids
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice botany metabolism, cell respiration, and photosynthesis light dependent or hill reaction phases of photosynthesis emerson's experiments & hill's reaction

When sun light hits the chloroplast, then

  1. Increase in $pH$ of thylakoid lumen relative to stroma occurs
  2. A measurable decreases in $pH$ in the thylakoid lumen relative to stroma occurs
  3. A measurable decrease in $pH$ in the stroma relative to thylakoid lumen occurs
  4. The $pH$ of both stroma and thylakoid luman becomes equal
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the light hits the chloroplast, the chemiosmotic potential is established by thylakoid membrane. The carriers in the electron transport chain use some of the electron’s energy to actively transport protons from the stroma to the lumen. During photosynthesis, the lumen becomes acidic, as low as pH 4, compared to pH 8 in the stroma. Therefore answer B is correct.

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

In plants, light-dependent reactions proceed at the

  1. cytoplasm

  2. stroma

  3. plasma membrane

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

In plants, the light reactions take place in the thylakoid membranes of organelles called chloroplasts. The light-dependent reactions use light energy to make two molecules needed for the next stage of photosynthesis: the energy storage molecule ATP and the reduced electron carrier NADPH. 

So, the correct option is, 'thylakoid membrane'.

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

Choose the correct answer from the alternatives given.
The first step in photosynthesis is

  1. formation bf $NADPH _2$

  2. photolysis of water

  3. formation of ATP

  4. excitation of an electron of chlorophyll by a photon of light
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

During the first stage of photosynthesis, called the light-dependent reaction, sunlight excites the electrons in the chlorophyll pigment. The organism uses this energy to create the energy carrier molecules ATP and NADPH, which are crucial for carbon fixing during the second stage. 

Thus, the correct answer is 'Excitation of an electron of chlorophyll by a photon of light.'

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

Photophosphorylation in chloroplast requires movement of:

  1. electrons across the membrane

  2. ions across the membrane

  3. protons across the membrane

  4. electrons and protons across the membrane
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Phosphorylation in the electron-transport chain in the mitochondrion.

Hence the correct answer is A.

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

Choose the correct answer from the alternatives given.
In a plant cell, which of the following pigments participates directly in the light reaction of photosynthesis

  1. chlorophyll a

  2. chlorophyll b

  3. carotenes

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

Green pigments are located within the chloroplasts of plant. Chlorophyll a can participate directly in light reaction which convert solar energy to chemical energy.

Thus, the correct answer is 'Chlorophyll a.'