Unit 4 Review AP

A signaling molecule is also called a(n)

• enzyme

• protein kinase

• ligand

• cAMP

Since most receptors are membrane proteins, which of the following is usually true?

• they change their conformation after binding with a ligand

• they open and close in response to protein signals

• they lead to changes in intracellular ion concentrations

• they are only attached to either the exterior or interior

Since steroid receptors are located intracellularly, which of the following is true?

• the receptors themselves are lipids or glycolipids

• the steroid/receptor complex can cross the nuclear membrane

• the unbound steroid receptors are recycled by lysosomes

• the receptor molecules are free to move into most organelles

Which of the following is the best explanation of why most STPathways have multiple steps?

• most steps were already in place in other pathways

• multiple steps requires the least amount of ATP

• multiple steps allow for greater amplification of a signal

• each step can remove excess phosphate groups from the cell

What happens during the first step of a STP?

• activation of a cellular response

• relay proteins and secondary messengers pass the signal

• a ligand binds to the receptor

• cells talk to each other

What is a G-protein?

• a protein that synthesizes GTP

• a protein activated by the transfer of a phosphate from GTP

• a protein that phosphorylates another protein

• a ligand that binds to GTP

In a ligand-gated ion channel, what triggers a cellular response?

• g proteins

• kinases

• the incoming ions

• the ligand

What is a second messenger?

• another ligand that binds to the outside of the cell

• the molecule that causes the signal to stop

• a tyrosine kinase signal

• internal signal molecules released due to external signal

Which of the following is not one of the steps in a STP?

• cellular response

• phosphorylation

• reception

• transduction

What is the process of amplification as it applies to a STP?

• active relay protein is able to activate many relay protein

• AMP is converted into cAMP

• a protein is phosphorylated

• a cellular response is minimized