Tag: modern concept of photosynthesis

Questions Related to modern concept of photosynthesis

Refer to the given reaction.
$2H _{2}O \rightarrow 4H^{+} + O _{2} + 4{e^-}$
Where does this reaction take place in the chloroplasts of plants?

botany photosynthesis modern concept of photosynthesis photosystems photosynthesis in higher plants

  1. Outer surface of thylakoid membrane

  2. Inner surface of thylakoid membrane

  3. In the matrix (stroma)

  4. Intermembrane space

Show answer
Correct Option: B
Explanation:
The splitting of water is associated with the PS II. Water is split into $H^{+},[O]$ and electrons. The electrons needed to replace those removed from photosystem I are provided by photosystem II. 
   $2H _{2}O\rightarrow  4H^{+} + O _{2} + 4 _{e^-}$
Water splitting complex is associated with the PSII, which itself is physically located on the inner side of the membrane of the thylakoid.
So the correct answer is 'Inner surface of thylakoid membrane'.

In the light reaction the energy is absorbed by chlorophyll. The absorbed energy is used in splitting the water molecule into its two components and releasing electrons $(H _2O\longrightarrow2H^+ +O _2+2e)$, this reaction is known as :

botany photosynthesis modern concept of photosynthesis photosystems photosynthesis in higher plants

  1. Analysis of water

  2. Photolysis of water

  3. Decomposition of water

  4. All above.

Show answer
Correct Option: B
Explanation:

In the light reaction of photosynthesis, chlorophyll molecule absorbs light energy, results in the splitting of water molecules, results in the release of protons, electrons and nascent oxygen. This process is called Photolysis of water. It occur in the lumen of thylakoid.

So, the correct option is ‘photolysis of water’

The process in which water is split during photosynthesis is

botany photosynthesis modern concept of photosynthesis photosystems photosynthesis in higher plants

  1. Photolysis

  2. Hydrolysis

  3. Plasmolysis

  4. Hemolysis

Show answer
Correct Option: A
Explanation:

Photolysis of water occurs at grana i.e., lumen side of grana thylakoid membrane with the help of water splitting complex or OEC (oxygen evolvong complex). This step is associated with PS- II of Z- scheme.

Three minerals Mn ion, ${Ca}^++,{Cl}^-$ are associated with splitting of water.
So, the correct answer is 'Photolysis'.

Oxygen is released in photosynthesis by

botany photosynthesis modern concept of photosynthesis photosystems photosynthesis in higher plants

  1. photophosphorylation

  2. photolysis of water

  3. photorespiration

  4. photons

Show answer
Correct Option: B
Explanation:

This part of photosynthesis occurs in the granum of a chloroplast where light is absorbed by chlorophyll; a type of photosynthetic pigment that converts the light to chemical energy. This reacts with water (H2O) and splits the oxygen and hydrogen molecules apart. In the first stage of photosynthesis light energy is absorbed by chlorophyll in plant cells. This light energy is then used to produce ATP and to split water into hydrogen and oxygen. The splitting of water is referred to as photolysis. 

So, the correct option is, 'photolysis of water'.