Photosynthesis And The Calvin Cycle

Question 1

•plants are photoautotrophs= use light and chemical energy to fix carbon

OILRIG= oxidation is loss, reduction is gain (of electrons)

• inorganic= non-living (oxidised)
• organic= living (reduced)

Answer 1

CHLOROPLASTS:
•their job is to carry out photosynthesis. The membrane of each thylakoids contains chlorophyll
•light-dependant reactions happen in thylakoid membranes
•Calvin cycle happens in stroma
•chlorophyll absorbs blue and red light but reflects green light, so green light is visible to human eye

Question 2

LIGHT-DEPENDANT REACTION:
(non-cyclic phosphorylation)
= electrons flow in straight lines and ADP—> ATP

•photosynthesis= 6CO2+ 6H2O+ light—> C6H12O6

Answer 2

• water is split into 1/2 O2 and 2H at P680
• an electron is transferred to P680, gaining energy as it enters
• light energy gives the electron more energy and it leaves travelling the membrane through membrane proteins
• it looses energy as it goes, driving the H+ pump
• arrives at P700 and gains energy again from light, passes through intrinsic protein releasing electron to reduce NAD+ to NADH
• the H+ ions from the H+ pump move back through the enzyme ATPase and hydrolyse ADP to ATP

Question 3

CALVIN CYCLE:
•ATP and NADH (products from the Light dependant reaction) are used to fix carbon into sugars

• carbon atoms from CO2 are fixed
• 3 stages: carbon fixation, reduction, regeneration

Answer 3

Broken down:

CARBON
• 3CO2 + 3RuBP= 6G3P
•1G3P leaves to make glucose
•5G3P recycled for 3RuBP

ATP
•9ATP—> 9ADP (altogether)
•6ATP—> 6ADP (reduction)
•3ATP—> 3ADP (regeneration)

NADPH
•6NADPH—> 6NADP (reduction)

Question 4

•takes 3 turns of Calvin cycle to produce 1 G3P molecule

2x G3P molecules= 1 molecule of glucose

So 6 turns of Calvin cycle= 1 molecule of glucose

Answer 4

F