Hydrophilic cell signaling

What are the two main groups of signaling molecules? (select 2)

• Hydrophilic, polar signaling molecules

• Hydrophobic, nonpolar signaling molecules

• Ionic, charged signaling molecules

• Covalent, bonded signaling molecules

Why is the polarity of hydrophilic signaling molecules significant? (select 2)

• Because the cell membrane is also composed of nonpolar lipids, hydrophilic signals cannot move through the cell membrane easily

• Because the cell membrane is also composed of polar lipids, hydrophilic signals can easily move through the cell membrane

• Because water is also non-polar, hydrophilic signals cannot move through extracellular fluids in the body

• Because water is also polar, hydrophilic signals can easily move through extracellular fluids in the body

Why can't hydrophilic signals pass through the cell membrane?

• The membrane is polar

• The membrane is semi-permeable

• The membrane is non-polar and has hydrophobic fatty acids

• The membrane is fully permeable

If the signal can't get through the hydrophobic membrane, what adaptation does the cell perform so that it can still catch the signal?

• It uses osmosis to transport the signal

• receptors located on the inside of the cell membrane

• receptors located on the outside of the cell membrane

• It changes the polarity of the membrane temporarily

What Is NOT one of the three groups of receptor proteins that bind with hydrophilic signaling molecules?

• G-protein coupled receptors

• Receptor-protein kinase

• Ligand-gated ion channels

• Intracellular receptors

What is similar about all hydrophilic receptor proteins?

• They are all lipid-soluble

• They all have slow reaction times

• They are all water soluble

• They all require direct contact with the signaling molecule

What is a characteristic of a G-protein coupled receptor?

• They are long-lived and respond slowly to environmental stimulus

• They are fast, short lived, and can respond to environmental stimulus quickly

• They require direct entry of the signaling molecule into the cell

• They are only activated by nonpolar signaling molecules

After the G-protein coupled reaction releases GDP molecules, what will this molecule turn into once activated?

• ATP

• cAMP

• GTP

• ADP

True or false:

GTP (activated GDP) is important because because it will be able to bind to a target protein and trigger an transduction pathway in the cell

• True

• False

When the G-protein activates adenylyl cyclase, what does this molecule do?

• Converts GTP to GDP which makes it able to bind to kinases

• Converts ATP to cAMP, which makes it able to bind to kinases

• Converts cAMP to ATP which makes it able to bind to kinases

• Converts GDP to GTP which makes it able to bind to kinases