1 Under what conditions will the activity of Glucose 6phosph

1) Under what conditions will the activity of Glucose 6-phosphate dehydrogenase be inhibited?

None of the choices listed

The cellular concentration of NADPH is high

The cell is experiencing low oxidative stress

The cellular concentration of NADP⁺ is high

More than one of these choices

2)

When blood glucose is below 5mM, which enzyme is most likely to convert it to glucose 6-phosphate?

Hexokinase I

Glucokinase

Hexokinase IV

All of the above

More than one of these choices

3)

Which of the following controls the total activity of an enzyme?

All of the choices listed

Ubiquitination

Phosphorylation/Dephosphorylation

mRNA translation on Ribosomes

Transcription of a specific gene

Solution

1). d). The cellular concentration of NADP+ is high

High ratio of NADPH/NADP+ inhibits Glucose-6-phosphate dehydrogenase (G6PDH), the usual ratio of NADPH/NADP+ is 100/1. Increased levels of NADP+ stimulates G3PDH.

Pentose phosphate pathway: In pentose phosphate pathway, NADP+ is reduced to NADPH during the oxidation phase. Glucose-6-phosphate dehydrogenase is the rate limiting enzyme of pentose phosphate pathway; it is activated by the NADP+, while NADPH inhibits the pentose phosphate pathway.