Chapter 11

Question 1

site of the light-dependant reaction

Answer 1

thylakoid membrane

Question 2

site of the light-independent reaction

Answer 2

stroma

Question 3

Photosynthesis equation

Answer 3

6CO2 + 6H20 ——> C6H12O6 + 602

Question 4

Light - dependant reaction key points

Answer 4

light is absorbed by chlorophyll, this boosts the energy of the electron so they leave the chloroplast ionising the chloroplast (photoionisation), the electron is taken up by an electron carrier in the thylakoid membrane, the electrons are then passed along a number of electron carriers, as the electrons travel along they give off bits of energy to the carrier, this energy is used to pump H+ ions from the stroma into thylakoid space, this creates a concentration gradient of protons across the membrane, the only place the H+ ions can diffuse back through is through ATP synthase, as the H+ ions diffuse through ATP synthase they catalyse the combination of ADP and phosphate to make ATP and the H+ ions reduce NADP

Question 5

Photolysis of water

Answer 5

2H20 —–> 4H+ + 4e- + 02

Question 6

Light independent reaction simply defined

Answer 6

carbon dioxide is absorbed and is used to synthesise organic molecules via the Calvin Cycle

Question 7

Calvin Cycle

Answer 7

Carbon dioxide reacts with RuBP catalysed by rubisco to form glcerate-3-phosphate, GP is then reduced to triose phosphate using ATP and reduced NADP from the light dependant reaction, some triose phosphate is used to regenerate RuBP and the rest is used to make useful compounds

Question 8

Saturation point definition

Answer 8

the point at which changing a particular factor no longer has an effect as another limiting factor takes over

Question 9

result of lower C02 concentrations

Answer 9

less CO2 can react with RuBP so less GP is made. As a result of less GP, less TP is made but the TP there was is converted into RuBP reducing TP and increasing RuBP

Question 10

result of lower light intensity

Answer 10

less light results in less TP being formed due too there being less reduced NADP and ATP from light dependent reaction to reduce GP to TP. Due to this GP levels increase and TP levels decrease. Due to there being no TP no RuBP can become synthesised

Question 11

result of change in temp

Answer 11

enzymes can become inactive at low temperatures or denature at high temperatures. As a result less GP is synthesised as rubisco will be less effective, less TP more RuBP