a What is the 2fold purpose of the Pentose Phosphate Pathway

a. What is the 2-fold purpose of the Pentose Phosphate Pathway (production of what 2 molecues)? b. Under what conditions is this pathway (PPP) extremely active? c. What is the typical ratio NAD^+. NADH in a cell, and what is the primary function of this coenzyme? d. What is the typical ratio NADP+: _ NADPH in a cell, and what is the primary function of this coenzyme?

Solution

ANSWER= a] The two fold purpose of pentose phosphate pathway is

1] NADPH = For the reductive biosynthesis .NADPH serves as a source of electrons for the reduction of molecules during biosynthesis

2] Ribose 5 phosphate = for nucleotide & nucleic acid biosynthesis

b] When the substrate NADP + is present then the ppp is extremely active

Glucose 6 - phosphate is converted into 6- phosphogluconolactone by the enzyme glucose 6 phosphate dehydrogenase (G6PD)

G6PD is an NADP dependend enzyme that converts glucose 6-phosphate to 6- phosphogluconolactone

c] the ratio of NAD : NADH = 3.1 TO 3.6

the primary function of NAD is

IN GLYCOLYSIS = NAD accepts 2 H+ & converts into NADH

in crebs cycle = NAD accepts 2 H+ & converts into NADH2

NAD is the main coenzyme of electron transport system i.e.ETS

NAD acts as a main electron carrier during ETS

as the electrons are transport through ETS there is synthesis of ATP takes place

d] Functions of NADP =IS a cofactor used in anabolic reactions such as lipid 7 nucleic acid synthesis which require NADPH as reducing agent

in photosynthetic organism NADPH is produced by ferredoxin NADP -Reductase in the last step of electron chain of light reactions of photosynthesis

it is used as a reducing power for the fixation of CO2 during calvin cycle

it is used to turn the carbon dioxide into glucose

also used to reduction of nitrate into ammonia for plant assimilation in nitrogen cycle