Biochem lecture 23- Citric Acid Cycle Part 1

When is insulin secreted?

In response to INCREASED BLOOD glucose levels

What does the uptake of insulin by the cells lead too?

It triggers the protein kinase cascade that leads to glycogen synthesis or stimulates the reaction of GLUT4

What I what does the insulin signaling pathway do?

It regulates glycogen synthase

What is the first step of the insulin signaling pathway?

insulin binds to its insulin receptor on the cell membrane, triggering protein kinase cascade

What is the second step in the insulin signaling pathway?

The pathway promotes the insertion of GLUT4 (a glucose transporter) into the plasma membrane and allows glucose to enter the cell from the bloodstream. Glucose is also phosphorylated to G6P in this step

What is the third step in the insulin signaling pathway?

Insulin signaling inactivates GSK3 via phosphorylation. When GSK3 is inactivated it allows glycogen synthase to remain active

What is the fourth step in the insulin signaling pathway?

Phosphatase-1 (PP1) plays a role in activating glycogen synthase by dephosphorylating it promoting glycogen synthase

What is the fifth step in the insulin signaling pathway?

Allosteric activation through glucose-6-phosphate enhances synthesis, allowing the cell to store excess glucose

In its active form what does glycogen synthase promote?

Glycogen synthesis, allowing the cell to store excess glucose

What are the products of the Pentose phosphate pathway?

NADPH and ribose-5-phosphate

what are some characteristics of NADPH?

-electron donor

-reductive biosynthesis of fatty acids and steroids

-repairs oxidative damage

What are some characteristics of ribose-5-phosphate?

-biosynthetic precursor of nucleotides

-used in DNA and RNA synthesis

-synthesis of select coenzymes