Question

Which describes the light-dependent stage of photosynthesis?
(Select all that apply.)

A) Hydrogen ions (H+) are moved against their concentration gradient.

B) Water is split, which produces oxygen.

C) Carbon dioxide is incorporated into a preexisting sugar molecule.

D) Photosynthetic pigments absorb energy from light.

Answer 1

Hi,
The anwer is: B and D.
In the light dependent photosyntesis stage the light is absorbed by the photosystems. The H2O is split to produce H+ and Oxygen. The H+ builds up with each successsiv round of water split. THe electrons from oxygen are transfered ultimately to NADP+ which gets reduced to NADPH. The H+ions move out of concentration gradient via ATP synthase thus producing ATP.
The addition of CO2 to sugar happens in light independent cycle also called Calvin cycle.