Lecture 6 and 7: Receptors and Signal Transduction

A set of flashcards covering key concepts and mechanisms related to receptors and signal transduction from the lecture notes.

What role does phosphorylation/dephosphorylation play in metabolic pathways?

It controls key enzymes in metabolic pathways.

What is unique about the phosphorylation event on enzymes?

Whether it activates or deactivates an enzyme is enzyme specific.

How do receptor/signal transduction pathways respond to stimuli?

They provide specific responses by activating select enzymes, amplifying signals, and inducing multiple intracellular changes simultaneously.

What are some major signaling pathways influenced by nutrition?

Cyclic AMP, AMP-Activated Protein Kinase, MAPK, DNA damage (ATM/ATR), Cell Cycle, Wnt / β-Catenin, and nuclear receptors.

What is the function of glycogen synthase in the liver?

It helps store excess carbohydrates as glycogen during nutrient consumption.

What happens in the liver during fasting?

The liver releases glucose from glycogen stores to supply the brain and heart.

What regulates glycogen phosphorylase activity in the liver?

cAMP which phosphorylates glycogen phosphorylase.

What hormones mediate the covalent regulation of glycogen phosphorylase?

Glucagon, catecholamines, epinephrine, and norepinephrine.

How is AMP related to glycogen phosphorylase's activation?

AMP acts as an allosteric activator, increasing the binding of glycogen when energy levels are low.

What is the role of AMPK in cellular energy sensing?

AMPK acts as a glucose sensor and becomes activated in low energy states, switching on ATP-generating pathways.