The synthesis of complex organic compounds from simple organic compounds like water and carbondioxide by green plants in the presence of chlorophyll using sunlight is called photosynthesis.

6CO₂+ 6H₂O CHO+6O

The pigments present in the plant cell that absorb sunlight and are responsible for photosynthesis are called photosynthetic pigments. For example:- chlorophyll, xanthophyll, carotene, etc.

Light reaction also called Light-dependent reaction or Hill's reaction is the first phase of photosynthesis in which production of chemical energy like NADPH2 and ATP take place in the presence of light. This reaction takes place in the grana membranes of the chloroplast.

Dark reaction, also called calvin cycle is an anabolic process in which 3-Carbon sugar called glyceraldehyde-3-phospate is produced. This is a light independent process.

Differences between cyclic and non-cyclic photophosphorylation are given below:-

It is the reaction which occurs in the stroma of chloroplast in absence of light or in dark condition. In this ATP and NADPH₂produced during light reaction are utilized as source of energy. It is studied in the following steps:-

1. Assimilation of carbondioxide or carboxylation:- It is the fixation of carbondioxide by RuBP in presence of RuBISCO enzyme. When RuBP reacts with carbondioxide, 6-carbon compound is formed which is unstable and converted into 3-carbin compound PGA phosphoglyceric...

When during hot, arid days, stomata opens only a little, enough carbon dioxide is not taken, so rubisco takes up oxygen and uses it in the Calvin cycle instead of carbon dioxide, this process of light dependent uptake of carbon dioxide and release of oxygen is called photorespiration.

The utilization of oxygen and release of carbondioxide in presence of light during high temperature and low concentration of CO₂is called photorespiration.

It proceed in the following mechanism:-

1. During high temperature, high concentration of O₂and low concentration of CO₂, the affinity of Ribulose bi-phosphate (RuBP) carboxylase for CO decreases and for O increases and form oxyɡenase which catalyse the oxidation of RuBP to form 3-PGA(3-phospgoglyceric acid) and 2-phosphoglycolate.

RuBP +O...

Differences between C3 cycle and C4 cycle are as follows:-

The major role of light during photosynthesis is toprovides energy for the synthesis of glucose from carbon dioxide and water. During light reaction, the chlorophyll entraps light and the solar energy is converted into chemical energy in the form of ATP molecules.

It is also a pathway for fixation and reduction of carbondioxide. It was discovered by Hatch and Slack in 1977. The first acceptor of CO₂is phosphoenol pyruvic acid and the first stable compound is oxalo acetic acid which is 4-carbon compound. So, this cycle is called C4 cycle. The anatomy of leaf of C4 plants is called krantz anatomy.

It is completed in the following ways:-

1. Fixation of CO takes place in mesophyll cell. In mesophyll cell, the affinity of PEP carboxylase (Phosphoenol pyruvic...

The significances of C4 plants are as follows:-

1. C4 plants have very low photorespiration.

2. C4 plants are more efficient in fixation of CO in low concentration of CO, because of high affinity of PEP.

3. Concentric arrangement of mesophyll cells produces a smaller area in relation to volume for better utilization of available water and reduces intensity of light.

4. They are adapted to high temperature (30 - 45C), intense radiation and saline condition.

5. Generally their product is higher than...

In photosynthesis, the source of oxygen is indeed water, but carbon dioxide (CO2) also plays a crucial role, the process and clarify the relationship between water and carbon dioxide in photosynthesis.

Photosynthesis is the biochemical process by which green plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose. It occurs in the chloroplasts of plant cells, specifically in the thylakoid membranes.

During the light-dependent reactions of...