8

Question 1

Photosynthesis is separated into

Answer 1

• light reactions

- calvin cycle

Question 2

the conversion of CO2 into an organic form is called— and how does it work

Answer 2

carbon fixation - a reduction reaction with electrons being added to CO2

Question 3

where does photosynthesis take place in a cell

Answer 3

the cholorplasts

Question 4

After the pigment molecule absorbs a photon of light in photosynthesis, one of three possible events can occur

Answer 4

• the excited electron returns to ground state and releases energy of a longer wavelength
• The energy of the excited electron is transferred to a neighbouring molecule in a process called inductive resonance
• the excited electron is transferred to an electron accepting molecule called a primary acceptor

Question 5

Difference between absorption spectrum and action spectrum

Answer 5

The absorption spectrum shows which wave lengths are absorbed in each individual type of chlorophyll. The action spectrum shows which wavelengths of light are most effective for photosynthesis.

Question 6

function of a photosystem

Answer 6

trap photons of light and use the energy to oxidize a reaction centre chlorophyll, with the electron being transferred to the primary electron acceptor

Question 7

The 3 key events that take place within photosystem II

Answer 7

1. The absorption of photons and energy to the reaction centre result in an electron within P680 being excited- now changed to P680*
2. P680* can be oxidized to P680+ by the primary electron acceptor
3. P680+ is reduced back to P680 by a donation of an electron from H2O

Question 8

Linear electron transport

Answer 8

The pathway of electron flow from photosystem II through photosystem I to synthesize NADPH

Question 9

3 main phases of one turn of the Calvin cycle are

Answer 9

1. Fixation - CO2 is added to RuBP making a rubisco, and then split into two PGA’s
2. Reduction - PGA is phosphorylated and then hydrogen is added to it.
3. Regeneration - in a series of reactions, ATP is used to rearrange 5 G3P into 3 RuBP

Question 10

summary of calvin cycle

Answer 10

CO2 is reduced and converted into carbs by adding electrons and hydrogen carried by the NADPH produced in light dependant reactions, ATP is also used

Question 11

oxygen is a —– of rubisco

Answer 11

competitive inhibitor, it competes with CO2 for the active site

Question 12

In aquatic photoautotrophs

Answer 12

an ATP process pumps bicarbonate into the cell which is converted to CO2 by a enzyme carbonic anhydrase