LDR

Question 1

Where does the light dependant reaction occur

Answer 1

-thylakoid membranes or grana

Question 2

Where does the light independent reaction occur

Answer 2

-the stroma

Question 3

What happens during the LDR

Answer 3

-light energy and water are used to create ADP and reduced NADP

Question 4

What happens during photolysis

Answer 4

Light energy is absorbed by chlorophyll and splits water into oxygen, H+ and e-
-The H+ is picked up by NADP to form NADPH and is used in the LIT
-The e- is passed along a chain of electron carrier proteins
-The oxygen is used for either respiration or diffuses out of the lead through the stomata

Question 5

What is the equation for photolysis

Answer 5

-H2O > 1/2 O2 + 2e- + 2H+

Question 6

What happens during photoionisation of chlorophyll?

Answer 6

• Light energy is absorbed by the chlorophyll and energy results in electrons (raising up in an energy level) to leave chlorophyll

Question 7

What has chlorophyll been ionised by?

Answer 7

-Light

Question 8

What is the energy from the released electrons used for?

Answer 8

-to make ATP and reduced NADP in chemiosmosis

Question 9

What happens during chemiosmosis

Answer 9

-The electrons that gained energy and left the chlorophyll move along a series of proteins embedded within the thylakoid membrane
-as they move along they release energy and some of the energy from the electrons is used to pump the protons along the chloroplast membranes
-an electrochemical gradient is created. The protons pass through the enzyme ATP synthase which results in the production of ATP

Question 10

What happens at the end of chemmiosmosis

Answer 10

-The protons combine with the co-enzyme NADP to become reduced NADP.

Question 11

Why is this stage known as chemiosmosis

Answer 11

-Because the protons move from a high to low concentration gradient

Question 12

What does photolysis of water produce?

Answer 12

Protons, electrons and oxygen

Question 13

In photosynthesis, which chemicals are needed for the light-dependent
reaction?

Answer 13

NADP, ADP, Pi and water

Question 14

Describe the method the student used to separate the pigments after the
solution of pigments had been applied to the origin.

Answer 14

Level of solvent below origin/line;
Remove/stop before (solvent) reaches top/end

Question 15

The pigments in leaves are different colours. Suggest and explain the
advantage of having different coloured pigments in leaves.

Answer 15

-absorbs different wavelengths for photosynthesis