Pentose Phosphate Pathway Flashcards
Which other metabolic process does the PPP mirror?
The Calvin Cycle
What are the two key Phases of the PPP?
Phase 1 = oxidative generation of NADPH
Phase 2 = non-oxidative (reversible)
Which organisms does the PPP take place?
ALL!
Where does the PPP take place?
Cytoplasm
What is the starting molecule in the PPP?
Glucose-6-Phosphate G6P
(Simply) Why are there different fates of G6P?
Dependent on cell’s requirements
What are the 2 main products of the first phase of the PPP?
Ribose 5-phosphate and Xylulose-5-phosphate
What are the intermediates between the oxidative decarboxylation of glucose 6-phosphate to ribulose 5-phosphate (6C to 5C)? PPP?
6-phsphoglucono-delta-lactone
then phosphogluconate
What carriers and small molecules are produced in the 1st, 2nd and 3rd step of converting G6P to ribulose 5-phosphate? PPP
1st = NADPH
2nd = H2O used to produce H+
3rd = NADPH and CO2
What enzyme is used in the first step of the conversion of G6P to ribulose 5-phosphate?
glucose 6-phosphate dehydrogenase
What enzyme is involved in the 2nd step in the oxidative decarboxylation of G6P to ribulose 5-phosphate?
lactonase
What enzyme is involved in the 3rd step in the oxidative decarboxylation of G6P to ribulose 5-phosphate?
6-phosphogluconate dehydrogenase
Which product of the first phase of the PPP can be diverted to other pathways?
Ribose -5- phosphate
Which enzyme is used in the reversible reaction producing ribose 5-phosphate in the first stage of the PPP?
phosphopentose isomerase
Which reaction does the enzyme phosphopentose epimerase catalyse in the PPP?
ribulose 5-phosphate to xylulose 5-phosphate
How many reactions are involved in phase 2 of the PPP?
3
What is the name of the 7C and 3C molecule produced in phase 2 of the PPP?
Sedoheptulose 7-phosphate
Glyceraldehyde 3-phosphate
What’s the name of the 4C molecule produces in phase 2 of the PPP?
erythrose 4-phosphate
What’s the name of the 6C molecule produced in phase 2 of the PPP?
fructose 5-phosphate
Ribose 5-phosphate (5C) and Xylulose 5-phosphate (5C) combine at the end of phase 1 of the PPP, does this produce 7C and 3C then 4C and 6C or the other way round?
Correct way round
In phase 2 of the PPP, 4C and 5C combine to produce which two molecules? (name and carbon number)?
3C GLyceraldehyde 3-phosphate
6C Fructose 6-phosphate
Which two enzymes are involved in phase 2 of the PPP?
Transketolase and Transaldolase
Which enzyme in phase 2 of the PPP has a coenzyme? and what is the coenzyme?
Transketolase has a TPP coenzyme
Which products of phase 2 of the PPP are glycolysis intermediates?
Glyceraldehyde 3-phosphate (3C)
Fructose 6-phosphate (6C)
Which 5C product of phase 1 of the PPP combines with the phase 2 4C molecule erythrose 4-phosphate to produce 3C and 6C?
Xylulose 5-phosphate
