Cyclic and Non-cyclic photophosphorylation
http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter8/cyclic_and_noncyclic_photophosphorylation.html
Light independent reaction
(k) outline how the products of the light dependent stage are used in the light independent stage (Calvin cycle) to produce triose phosphate (TP) (reference should be made to ribulose bisphosphate (RuBP), ribulose
bisphosphate carboxylase(rubisco) and glycerate 3-phosphate (GP), but no other biochemical detail is
required);(l) explain the role of carbon dioxide in the light-independent stage (Calvin
cycle);
aka Dark Reaction aka Calvin Cycle aka Carbon Fixation Reaction
Photosynthetic electron-transfer
reactions in thylakoid
membrane
ATP NADPH
Carbon-fixation reactions in
stroma
Sugars, amino acids and fatty
acids
Water
Carbon dioxide
Oxygen
+
ChloroplastCytosol
LDR
LIR
Word ladder
• Toad• ----• ----• ----• ----• ----• ----• ----• ----• Frog
• Toad• (street)• (leaf through)• (toward the back)• (phobia)• (achievement)• (level or smooth)• (banner)• (whip)• Frog
• Toad• road• read• rear• fear• feat• flat• flag• flog• Frog
Phase one – carbon fixation
Ribulose bisphosphate (RuBP)
(aka ribulose biphosphate)
(aka ribulose 1,5 bisphosphate)
Ribulose bisphosphate carboxylase (RuBisCo)
Glycerate 3-phosphate
(GP)(aka 3-phosphoglycerate)
2X
Phase two – reduction (part one)
Glycerate 3-phosphate
(GP)(aka 3-phosphoglycerate)
1,3-bisphosphoglycerate
(GP)
Triose Phosphate (TP)
(aka glyceraldehyde-3-phosphate)
(aka G3P)
Phase two – reduction (part two)
1,3-bisphosphoglycerate
(GP)
Regeneration Several steps
Triose Phosphate (TP)
(aka glyceraldehyde-3-phosphate)
(aka G3P)
Ribulose 5-phosphate
Return to the start
Ribulose bisphosphate (RuBP)
(aka ribulose biphosphate)
(aka ribulose 1,5 bisphosphate)
Ribulose 5-phosphate
Glycerate 3-phosphate
2. Reduction
1. Carbon fixation
6x Triose phosphate
1x Triose phosphate
5x Triose phosphate
3. RuBP is regenerated from triose phosphate
Calvin Cycle/LIR
Glucose
Glycerate 3-phosphate
2. Reduction
1. Carbon fixation
6x Triose phosphate
1x Triose phosphate
5x Triose phosphate
3. RuBP is regenerated from triose phosphate
Calvin Cycle/LIR
Glucose
The role of Carbon Dioxide
Useful Animation
• http://www.science.smith.edu/departments/Biology/Bio231/calvin.html
• http://highered.mcgraw-hill.com/sites/007337797x/student_view0/chapter7/animation_quiz_-_how_the_calvin_cycle_works.html
Summary test…• The light independent reaction is also
known as the (1) cycle. In the process, carbon dioxide combines with a 5-carbon compound called (2) to form a 6-carbon intermediate that immediately splits into 2 molecules of (3). By the addition of (4) and (5) formed in the (6) reaction, each of these molecules is converted into a (7) molecule. These combine to form a (8) sugar that can then be made into starch by a process called (9).
Glycerate 3-phosphate
2. Reduction
1. Carbon fixation
6x Triose phosphate
1x Triose phosphate
5x Triose phosphate
3. RuBP is regenerated from triose phosphate
Calvin Cycle/LIR
Glucose
Can be used to make carbohydrates, lipids or amino acids
Cyclic photophosphorylation