Quiz 16

10 Questions

The first step in a signaling pathway that responds to a molecule that stays in the extracellular space is

binding of the signal molecule to a receptor.

What type of cell response would take the longest amount of time (on the scale of minutes to hours) to execute?

one that involves a change in gene expression

Which of the following is NOT an intracellular signaling protein activated by an RTK?

G-protein

Steroid hormones trigger transcription of target genes by

binding to nuclear receptors that act as transcription factors for specific genes.

Which of the following types of cell signaling is long range and uses hormones as signals?

endocrine

The active form of a monomeric GTP-binding protein is the

GTP-bound form.

Which of the following describes negative feedback regulation?

A component late in the pathway inhibits an enzyme early in the pathway.

Enzymes that add a phosphate group to a switch protein are called

kinases.

How does the binding of a signal molecule activate an RTK for downstream signaling?

The RTK forms a dimer and cross-phosphorylates itself.

Shown below is a diagram of how theoretical intracellular signaling pathways could integrate incoming signals to produce a coordinated cell response.

signals A and D

Study Notes

Cell Signaling

Signaling pathways that respond to molecules in the extracellular space start with the binding of the molecule to a receptor on the cell surface.

Cell Response Timing

Cell responses that take the longest amount of time (on the scale of minutes to hours) to execute are typically transcriptional responses.

Intracellular Signaling Proteins

One protein that is NOT activated by an RTK (Receptor Tyrosine Kinase) is G protein.

Steroid Hormone Signaling

Steroid hormones trigger transcription of target genes by binding to intracellular receptors.

Long-Range Cell Signaling

Long-range cell signaling that uses hormones as signals is endocrine signaling.

Monomeric GTP-Binding Proteins

The active form of a monomeric GTP-binding protein is the GTP-bound form.

Negative Feedback Regulation

Negative feedback regulation occurs when the product of a pathway inhibits an earlier step in the same pathway.

Protein Phosphorylation

Enzymes that add a phosphate group to a switch protein are called protein kinases.

RTK Activation

The binding of a signal molecule to an RTK (Receptor Tyrosine Kinase) activates it for downstream signaling by causing the receptor to dimerize and autophosphorylate.

Intracellular Signaling Pathway Integration

Intracellular signaling pathways can integrate incoming signals to produce a coordinated cell response by converging on common signaling components or by having opposing effects on a shared target.