Photosynthesis (Biology)

Question 1

What is a light dependent reaction ?

Answer 1

• Light dependent reaction needed light.
• They are located in tharlokoid membrane of the chloroplast.
• During light independent reaction, light is used to add a phosphate group to ADP t form ATP, and reduce NADP to NADPH.
• Water is also oxidised to Oxygen.

Question 2

Please tell me the process of chemiosmosis in light dependent reaction

Answer 2

• First light energy hit the photosystem II, this causes the electrons in the photosystem 2 to be excited and they go started moving along the electron chain, to PSII
• During this time the electron started losing its energy, this is because all the energy went to actively transport protons from the stroma to the thylakoid membrane.
• Then, the protons in the tharlakoid membrane are transport down their concentration gradient via ATP synthase ( enzyme ) —-> allow phosphorylation to happens ADP+ Pi —-> ATP

Question 3

What happens in photosystem 1?

Answer 3

During photosystem 1, the light hit again and the electron become excited and they combine with the protons in the stroma and redice NADP to NADPH.

Question 4

What is the cyclic phosphorylation ?

Answer 4

During this time, electron produced by the PSI is move back to the electron chain in PSII, when this happens only ATP can be produced.