Ch. 16 Pt. II - Cell Signaling and Ion Channels

These flashcards cover key concepts related to cell signaling and ion channels, addressing mechanisms, types, and implications in biology.

What are ion channels?

Highly selective, narrow pores allowing passage of one type of charged ion through the membrane while excluding others.

What is endocrine signaling?

A form of long distance intercellular communication where hormones are released into the bloodstream to reach distant target cells.

What is paracrine signaling?

A type of short distance intercellular communication where signaling molecules diffuse over short distances to reach target cells.

What is contact dependent (juxtacrine) signaling?

A form of intercellular communication where a membrane-bound protein on one cell directly interacts with a receptor on an adjacent cell.

What is autocrine signaling?

A type of cell signaling where a cell releases a signaling molecule that binds to receptors on the same cell (self-signaling).

What is signal transduction?

The process of converting external signals into intracellular responses.

What role do effector proteins play in signaling?

Effector proteins carry out the cellular response to a signaling pathway.

What do second messengers do in a signaling pathway?

Second messengers amplify the strength of the signal received from the receptor.

Name some examples of second messengers.

cAMP, IP3, Ca2+.

What are the three main types of cell surface receptors?

G-protein-coupled receptors, ion channel-linked receptors, enzyme-linked receptors.

What is the function of G-protein-coupled receptors (GPCRs)?

They elicit intracellular responses activated by signaling molecules (ligands) that trigger intracellular signaling pathways.

What happens when ion channels are open?

Ions flow rapidly through the channels, down their electrochemical gradients.

What is the difference between ion channel-linked receptors and ion transporters?

Ion channel-linked receptors act as gates allowing ions to move, while ion transporters act as pumps moving ions against their electrochemical gradient.

How does the membrane potential influence passive transport?

The unequal distribution of charged ions gives rise to the membrane potential, influencing the movement of charged solutes across the membrane.

What can the concentration gradient and membrane potential do?

They can work in the same direction or in opposite directions concerning the electrochemical gradient.

What is an example of a signaling molecule used in synaptic signaling?

Acetylcholine.

Why do neurons rely on ligand binding for signaling?

For rapid signal transmission between neurons.

What are the characteristics of autocrine signaling?

Signaling cell releases a signaling molecule that acts only on itself, promoting growth and survival of the signaling cell.

What is the function of the Notch receptor in contact-dependent signaling?

It interacts with the membrane-bound ligand Delta, facilitating intercellular communication.

What can uncontrolled cell signaling lead to?

Cancer, including sustained cell proliferation, evasion of growth suppressors, and enabling replicative immortality.

List some responses to extracellular signals that occur in cells.

Altered metabolism, gene expression, cell shape, and movement.

What role does the PI3K-Akt pathway play in cell survival?

It regulates cell survival by affecting pro-apoptotic and anti-apoptotic proteins such as BAD and Bcl2.

What is the function of the hormone insulin in endocrine signaling?

Insulin binds to target cells in other organs to initiate cellular responses.

What is an example of paracrine signaling during tissue repair?

Cells near a wound release growth factors to promote repair.

Describe the function of GPCRs in signal transduction pathways.

They activate intracellular signaling pathways via G-proteins leading to cellular responses.

How does ligand binding affect ion channel receptors?

Ligand binding induces conformational changes that open the ion channel, allowing ion flow.

What are the consequences of evading cell death in cancer cells?

It contributes to tumor survival and progression.

Define the term 'electrochemical gradient'.

The net sum of the concentration gradient and the membrane potential affecting ion movement.

What is the typical charge distribution on either side of a cell's membrane?

The outside is typically positive (high Na+) and the inside is negative (high Cl-).