Photosynthesis

Question 1

What is chlorophyll

Answer 1

A group of photosynthetic pigments

Question 2

role of chlorophyll

Answer 2

absorbs light energy at specific wavelengths of light (for photoionisation)

Question 3

describe photoionisation

Answer 3

• chlorophyll absorbs light energy
• Electrons in chlorophyll get excited to a higher energy level

Question 4

Role of accessory pigments

Answer 4

helps channel light energy to primary pigments

Question 5

What is the absorption spectra

Answer 5

absorbance of specific wavelengths of light by specific pigments

Question 6

describe the absorption spectra in regards to multiple pigments

Answer 6

• more pigments
• more wavelengths of light absorbed
• more efficient photosynthesis

Question 7

What is the action spectra

Answer 7

the effectiveness of different wavelengths of light on the rate of photosynthesis

Question 8

at what point on the action spectra is photosynthesis most effective

Answer 8

when both pigments are absorbing their peak wavelength of light

Question 9

what time of pigment should light energy be channeled to

Answer 9

primary pigment

Question 10

describe reduction

Answer 10

gain of electrons + hydrogen ions

Question 11

describe oxidation

Answer 11

loss of electrons + hydrogen ions

Question 12

Summarise LDR (6)

Answer 12

• occurs in thylakoid membrane/grana
• light energy is absorbed by pigments
• photolysis splits water molecules into hydrogen ions, electrons and oxygen
• electrons energised to a higher energy level
• high energy electrons generate ATP through phosphorylation
• high energy electrons reduce NADP to reduced NADP

Question 13

photolysis equation

Answer 13

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

Question 14

describe photolysis

Answer 14

water molecules split into H+ Ions, electrons and oxygen. low energy electrons released from photolysis to replace those that left the reaction center

Question 15

Describe the process of chemiosmosis (6)

Answer 15

• electrons move down electron transfer chain, lose energy
• energy from electrons used to actively pump protons into the thylakoid space
• sets up a proton gradient across the thylakoid membrane
• facilitated diffusion of protons through channel protein down their concentration gradient into stroma
• flows through ATP synthase
• lead to photophosphorylation of ADP to form ATP (ADP + Pi)

Question 16

what is another name for the LIR

Answer 16

the calvin cycle

Question 17

Describe the Calvin Cycle

Answer 17

• Enzyme rubisco (ribulose bisphosphate carboxylase) catalyses the reaction between CO2 and the 5C compound RuBP (ribulose bisphosphate)
• forms unstable 6C compound, breaks down into 2,3C compounds of glycerate-3-phosphate (GP)
• Reduced NADP oxidised, energy released from hydrolysis of ATP allows for the reduction of GP into triose phosphate (TP)
• energy from hydrolysis of ATP converts some TP into glucose, amino acids, and lipids
• 5/6 of TP regenerated back into RuBP using energy from the hydrolysis of ATP.