AP BIOLOGY: UNIT 4, TOPICS 1,2,3,4

What is the most common second messenger

cyclic AMP (cAMP)

Direct contact, animals

gap junctions

Example of direct contact

immune cells

Synaptic signaling

in the animal nervous system; specialized type of local signaling Neuron secretes neurotransmitters that diffuse across synaptic cleft

long distance signaling

plants and animals use chemicals called hormones

Direct contact, plants

plasmodesmata

Receptor

protein that detects a signal molecule and performs an action in response

Intracellular receptors

small or nonpolar ligands can diffuse across the cell membrane

How can signal transduction pathways change as cell

Change in gene expression and cell function which can alter phenotypes

Ligand binding causes...

Cytoplasmic side to change shape, allowing G protein to bind to GPCR

Cell communicate through three general ways...

Direct contact, local signaling, and long distance signaling

Animal long distance signaling

Endocrine signaling Specialized cells release hormones into the blood stream ( circulatory system )

What are the two main categories of cell membrane receptors

G protein coupled receptors (GPCRs) Ion channels

Plasma me,brand receptor examples

G protein, ligand gated ion channels

Cell communication is responsible for what

Growth/development of multicellular organisms

Signal transduction law at hay's can influence

How a cell responses to its environment

Plasma membrane receptors

Large, polar, hydrophilic(most common in signaling pathways)

G protein is inactive until

Ligand bind to GPCR on extra cellular side

What will changes in the signal transduction pathways lead to

Mutations to receptor proteins or to any component of the signaling pathways

What are ion channels important in

Nervous system

2 examples of local regulators?

Paracrine and synaptic

In direct contact, signaling substances and other material dissolved in the cytoplasm can...

Pass freely between adjacent cells.

How does the signal transduction pathway regulate protein

Phosphorylation by enzyme kinase Depphosphorylation by phosphatase (shuts off pathways)

Where are Jon channels located

Plasma membrane

Receptors can be in the

Plasma membrane or intracellular fluid

3 steps of cell-to-cell messaging

Reception, transduction, response

Ion channels

Receptors that act as a gate for ions,,, When ligand binds to receptor, gate opens or closes allowing for the diffusion of specific ions (leads to cellular response )

Plants long distance signaling

Release hormones I plant vascular tissue (xylem or pholem) or through air to reach target

Insulin

Released by pancreas into bloodstream where it circulates in the body

local regulators

Secreting cell that will release chemical messages through extra cellular fluid

Paracrine signaling

Separatory cell releases messages (via Exocytosis) to adjacent cell

Second messengers

Small, non-protein water soluble molecules or ions that send messages throughout the cells by diffusion and amplify the response

Intracellular receptor examples

Steroid/Hormone nuclear receptors Gases

Transduction

The conversion Of an extra cellular signal to intracellular, signaling that will bring about a cellular response

Response

The final molecule in the signaling pathway will convert the signal to a response they will alter a cellular response.

When a ligand binds to a receptor

The receptor undergoes a conformational change and activates

Reception

The target cell's detection of a signal molecule coming from outside the cell.

When is the signal amplified

Transduction

What does transduction require.

a sequence of changes in a series of molecules known as a signal transduction pathway

GPCRs

animal sensory system Largest categories of cell surface receptors Binds to G protein that binds to GTP

direct contact

communication through cell junctions