Biosignaling - G-protein-coupled Receptors cAMP & Adenylate Cyclase

The video tutorial explores bio signaling pathways, focusing on G protein-coupled receptors (GPCRs) and their role in signal transduction. It explains how external signals like epinephrine bind to receptors, causing conformational changes that activate G proteins. This activation leads to the production of cyclic AMP, which in turn activates protein kinase A, initiating a cascade of phosphorylation events. The video also discusses the regulation of G protein activity and the importance of cyclic AMP in cellular responses.

What is the primary function of bio signaling pathways?

• To break down proteins into amino acids

• To store energy in the form of ATP

• To convert external signals into cellular responses

• To transmit signals from inside the cell to the outside

Which receptor is an example of a G protein-coupled receptor discussed in the video?

• Thyroid hormone receptor

• Estrogen receptor

• Beta adrenergic receptor

• Insulin receptor

What happens to the G protein alpha subunit when it binds GTP?

• It becomes inactive

• It degrades into smaller peptides

• It binds more tightly to the receptor

• It dissociates from the beta and gamma subunits

What is the role of adenylate cyclase in the signaling pathway?

• To convert ATP into cyclic AMP

• To phosphorylate proteins

• To bind to epinephrine

• To degrade cyclic AMP

How does cyclic AMP activate protein kinase A?

• By binding to its regulatory subunit

• By binding to its catalytic subunit

• By degrading it

• By phosphorylating it

What is the function of protein kinase A in the signaling cascade?

• To bind to GTP

• To phosphorylate other proteins

• To convert ATP into cyclic AMP

• To degrade glycogen

What is the inactive form of glycogen phosphorylase called?

• Phosphorylase B

• Glycogen hydrolase

• Phosphorylase A

• Glycogen synthase

What intrinsic activity does the G protein alpha subunit possess?

• Phosphatase activity

• Kinase activity

• GTPase activity

• ATPase activity

How is the G protein alpha subunit turned off?

• By binding to ATP

• By hydrolyzing GTP to GDP

• By binding to cyclic AMP

• By dissociating from the receptor

What is the purpose of having a regulatory mechanism in the G protein cycle?

• To ensure continuous activation of the pathway

• To prevent the pathway from being activated

• To allow the pathway to be turned off when necessary

• To increase the production of cyclic AMP