The video tutorial explains the IP3 pathway, detailing the roles of first and second messengers in cellular responses. It describes how extracellular ligands bind to G protein-coupled receptors, leading to the activation of phospholipase C, which cleaves PIP2 into IP3 and DAG. IP3 facilitates calcium release from the endoplasmic reticulum, while DAG and calcium activate protein kinase C, resulting in phosphorylation of target proteins and a cellular response.

What is the role of the first messenger in the IP3 pathway?

• It acts as an intracellular molecule.

• It binds to a G protein-coupled receptor.

• It cleaves PIP2 into IP3 and DAG.

• It releases calcium from the endoplasmic reticulum.

Which molecule acts as a precursor for DAG and IP3?

• PIP2

• Calcium

• Protein kinase C

• Phospholipase C

Which of the following is NOT a second messenger in the IP3 pathway?

• IP3

• Phospholipase C

• DAG

• Calcium

What is the function of phospholipase C in the IP3 pathway?

• It binds to the G protein-coupled receptor.

• It releases calcium from the endoplasmic reticulum.

• It cleaves PIP2 into IP3 and DAG.

• It phosphorylates target proteins.

How does IP3 contribute to calcium release in the cell?

• It opens the IP3 calcium channel on the endoplasmic reticulum.

• It phosphorylates target proteins.

• It binds to the G protein-coupled receptor.

• It activates protein kinase C.

What is the role of DAG and calcium in the activation of protein kinase C?

• They bind to the G protein-coupled receptor.

• They cleave PIP2 into IP3 and DAG.

• They lead to the activation of protein kinase C.

• They activate phospholipase C.

What is the ultimate result of protein kinase C activation in the IP3 pathway?

• Binding to the G protein-coupled receptor.

• Opening of the IP3 calcium channel.

• Cleaving PIP2 into IP3 and DAG.

• Phosphorylation of target proteins.