photosynthesis 6 light independent reaction

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

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