Cell Signaling

Question 1

What are the three modes of cell signaling

Answer 1

• Direct contact via receptors
• Signal protein moves from one cell to another via interstitial fluid
• Signal protein moves from one cell to another via bloodstream

Question 2

Direct contact via receptors

Answer 2

• contact dependent
• immune signaling
• We want immune response to be quick

Question 3

Signal protein moves from one cell to another via interstitial fluid

Answer 3

• Paracrine
• Neurotransmitter
• Close to each other
• Its quick

Question 4

Signal protein moves from one cell to another via bloodstream

Answer 4

• Neurotransmitters
• Hormonal
• Further apart
• Its slow/takes long

Question 5

Ligand Ion Channels

Answer 5

Examples: Nicotinic Receptors, GABA Receptors

Ligand binds to receptor, opens and lets ions through

Question 6

G-Protein Coupled Receptors

What are the steps for it?

Answer 6

Examples: Serotonin, Histamines and Opoid Receptors

1. Ligand attaches
2. Serious of reactions, complex molecule separates GDP – GTP
3. Second messengers (does the work in cell)

Question 7

Enzyme-Linked Receptor

Answer 7

Example: Growth Hormone, 2nd messenger system

Molecules link with two separate receptors and close molecules together

The work is done intercellular and perform by an enzyme called “Tyrosine kinase”

Question 8

Intracellular Receptors

Answer 8

Example: Replication, transcription and translation

Receptors located inside the cell

Lipophilic ligands bind and go directly in, they DON”T need carrier protein

Question 9

Signal Transduction

Answer 9

Activates a receptor on cell surface

Regulate gene expression
Amplifies signal
Results in divergent intracellular responses