Question

How do autotrophs capture the energy in sunlight?

Answer 1

Sunlight is absorbed by the green pigment, chlorophyll and the solar energy is converted into chemical energy in the form of `"ATP"`.

Explanation:

Autotrophs capture sunlight by the pigment chlorophyll and is used for the synthesis of glucose `(C_6H_12O_6)` from simple, inorganic substances like `CO_2` and `H_2O` during photosynthesis.

Photosynthesis occurs in 2 steps:

1. Hill's reaction

2. Dark reaction

Light reaction or Hill's reaction involves capturing sunlight and converting solar energy into chemical energy in the form of `"ATP"`. This occurs by breakdown of water into `H^+` ions and `O^(2-)` ions. This is termed by photolysis of water. Excited electrons from `O^(2-)` pass through a series of electron carriers, losing energy during their passage. This energy is converted into `"ATP"`. The remaining`H^+` ions reduce `"NADP"` to `"NADPH"`.

`"ATP"` and `"NADPH"` produced during light reaction are used in the dark reaction for reduction of `CO_2` to `C_6H_12O_6`.