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Only need help with Question 1. Biochemistry 361 Quiz #4 Chapters 8, 9 and 10 1.

ID: 548288 • Letter: O

Question

Only need help with Question 1.

Biochemistry 361 Quiz #4 Chapters 8, 9 and 10 1. (4 pts) What pathway do the following allosteric enzymes regulate and what molecule (substrate) goes into the enzyme's catalyzed reaction: Pathway Molecules ) produced by this a . glycogen phosphorylase b. pyruvate carboxylase c. glucose-6-phosphate dehydrogenase d phosphofructokinase-1 (PFK-1) 2. (2pts) In the electron transport chain, a pair of electrons are transferred from NADH to Oxygen to make Water: NADH + H +0.50 ,– NAD +HO The standard reduction potentials for the halfreactions are given below: NAD + 2e +H – NDH E= -0320V 0.50, + 2 +2H – H20 EQ >. = 0.816V

Explanation / Answer

A.Glycogen phosphorylasecatalyzes the rate-limiting step in glycogenolysis in animals by releasing glucose-1-phosphate from the terminal alpha-1,4-glycosidic bond.

B. Pyruvate carboxylase (PC) is an enzyme of the ligase class that catalyzes (depending on the species) the physiologically irreversible carboxylation of pyruvate to form oxaloacetate (OAA).

C.

D-glucose 6-phosphate + NADP+ {displaystyle ightleftharpoons } [ ightleftharpoons] 6-phospho-D-glucono-1,5-lactone + NADPH + H+

This enzyme participates in the pentose phosphate pathway (see image), a metabolic pathway that supplies reducing energy to cells (such as erythrocytes) by maintaining the level of the co-enzyme nicotinamide adenine dinucleotide phosphate (NADPH).

D.PFK-1 catalyzes the important "committed" step of glycolysis, the conversion of fructose 6-phosphate and ATP to fructose 1,6-bisphosphate and ADP.