Cell Communication and Signaling

Flashcards about cell signaling and communication for exam review.

What two processes are balanced to regulate growth vs. cell death?

Cell division and apoptosis

What is apoptosis?

Triggered process with internal fragmentation of cell parts; programmed cell death.

What is necrosis?

Cell death due to injury, releasing cell material that damages surrounding cells.

Which protein inhibits apoptosis?

Bcl-2

Which proteins stimulate apoptosis?

Bak and Bax

What triggers apoptosis initially?

Bak or Bax insertion into the mitochondrial membrane.

What leaks out of the mitochondria to activate caspases?

Cytochrome C

What occurs after caspases are activated during apoptosis?

Breakdown of the cytoskeleton, DNA, and nuclear envelope.

What are the types of cell communication in animals?

Endocrine, paracrine, neuronal, contact-dependent

What characterizes endocrine signaling?

Release of hormones into the circulatory system.

What diffuses over a short distance in paracrine signaling?

Local mediator, such as growth factors.

What is neuronal signaling?

Signals released by neurons called neurotransmitters that interact with target cells at synapses.

What are the components involved in cell communication?

Signaling Cell, Signal Molecules, Target Cell, Receptor

What are examples of signal molecules?

Proteins, short peptides, gas molecules, steroids, etc.

What is the role of a receptor?

Protein that binds to signals, allowing the target cell to respond.

What are the basic steps of cell communication?

Reception, Transduction, Response

What happens during reception?

Signal molecule interacts with a specific receptor at the target cell.

What is a key outcome of reception?

Change in receptor shape, which activates another protein.

What occurs during transduction?

Additional proteins/molecules are activated to continue the signal internally.

What happens during the response stage of cell communication?

Cell responds to the signal.

What are types of responses in cell communication?

Metabolism/chemical reactions, altering gene expression, changes to the cytoskeleton, etc.

What are the two main types of receptors?

Cell-surface receptors and intracellular receptors.

What type of molecules bind to cell surface receptors?

Large, polar, or charged molecules.

What type of molecules bind to intracellular receptors?

Small, hydrophobic, uncharged molecules.

Which pathway in the nervous system stimulates endothelial cells to regulate blood pressure?

Nitric oxide (NO) pathway.

How does nitric oxide affect smooth muscle cells?

It diffuses into surrounding smooth muscle cells, causing them to relax.

How does nitric oxide affect blood flow?

It prevents the breakdown of cGMP, which raises blood flow.

What are examples of pathways that utilize intracellular receptors?

Steroid and thyroid hormone pathways.

What is a major effect of steroid hormone pathways?

Change in gene expression.

What are the types of cell surface receptors?

Ion channel-linked receptors, G-protein linked receptors, Enzyme-linked receptors

What is an example of an ion channel-linked receptor?

Acetylcholine receptor.

What happens when acetylcholine binds to its receptor?

It opens, allowing Na+ to flow through and is involved in skeletal muscle contraction.

How is a G protein-coupled receptor pathway turned off?

Breaks down GTP into GDP.

What are the targets of the active alpha subunit in G protein signaling?

Adenylyl cyclase and phospholipase C

What are examples of enzyme-linked receptors?

Receptor tyrosine kinase pathway and JAK-STAT pathway

What is the main function of the receptor tyrosine kinase pathway?

Triggers cell growth and development.

What is the role of the JAK-STAT pathway?

Immune response to viral infections.

In summary, what determines which pathways are activated in cell communication?

Different combinations of signals can lead to different pathways being turned on.

Which cell communication pathway does Viagra affect?

Nitric oxide pathway

In cell communication with starfish cells, what is a result of activation of adenylyl cyclase

Increases cAMP levels.