Module 21 Terms - Signal Transduction

Question 1

What are the 2 broad groups of signaling molecules?

Answer 1

Hydrophobic polar and hydrophilic nonpolar signaling molecules

Question 2

What are the 3 groups of receptor proteins that bind HYDROPHILIC signaling molecules?

Answer 2

G protein-coupled receptors, receptor-protein kinases, and ligand-gated ion channels

Question 3

Amplification

Answer 3

Increase in volume of an original message

Question 4

G protein-coupled receptor

Answer 4

A type of receptor protein that, when activated, uses a molecule called a G protein as a part of the signal transduction pathway

Question 5

Second messenger

Answer 5

An intermediate signaling molecule that amplifies the response inside the cell

Question 6

Kinase

Answer 6

An enzyme that, when activated, catalyzes the transfer of a phosphate group from ATP to proteins

Question 7

Signaling cascade

Answer 7

When a small amount of signal is amplified to produce a large cellular response

Question 8

Receptor-protein kinase

Answer 8

Have a ligand-binding part outside the cell and a kinase section of the receptor on the inside of the cell. Works in a similar way to G protein-coupled receptors, except the receptor and kinase are coupled

Question 9

Ligand-gated channel

Answer 9

A receptor protein that includes a membrane-spanning channel that opens or closes (is gated) in response to binding a signaling molecule

Question 10

How do hydrophobic signaling molecules deliver their signal?

Answer 10

They are hydrophobic, which allows them to diffuse through lipid cell membranes to receptors floating in the cytoplasm

Question 11

What is the key difference between the responses produced by hydrophobic and hydrophilic signaling molecules?

Answer 11

Hydrophilic signaling molecules produce short-term effects that quickly wear off (an example being adrenaline) while hydrophobic signaling molecules cause changes in gene expression, producing long-term effects (an example being testosterone)