Ap Bio Cell Communication

examples of animal cell communication

1. direct contact (gap junctions)

2. secreting local regulators

3. long distance

example of secreting local regulators

growth factors, neurotransmitters

example of long distance communication

hormones

reception

detection of a signal molecule (ligand) coming from outside the cell

ligand

a signal molecule

transduction

converting a signal to a form that can bring about a cellular response

reponse

specific cellular response to a given signal

reception: binding between a _____ and _____

ligand, receptor

plasma membrane receptor

have water-soluble ligands that can’t get through the membrane passively

intracellular receptor

have small / hydrophobic ligand molecules

where are intracellular receptors found

cytoplasm / nucleus

how does a transduction signal occur

ligand binds to receptor →protein changing shape

name a type of major receptor

g protein-coupled receptor (GPCR)

ligand-gated ion receptor

where is GPCR found

cell surface

where is ligand-gated ion channel found

cell membrane

ligand-gated ion channel function

has a “gate” for ions when the receptor assumes a certain shape

what is the purpose of ligand-gated ion channel

to allow / block the diffusion of a specific ion through a channel in the protein

what step is after reception

transduction

summary of transduction

a multistep path that involves many molecules to relay a signal by a certain process

phosphorylation

addition of a phosphate group

dephosphorylation

removal of a phosphate group

relay moelcule

molecules that pass along the response (typically proteins)

what does the (de)phosphorylation do in terms for transduction

changing the shape of the protein causes the signal to be passed on

kinase

an enzyme that transfers phosphate groups from ATP to protein (phosphorylation)

phosphatase

enzyme that remove phosphate groups from proteins (dephosphorylation)

deactivates kinase

second messengers

small, nonprotein, water soluble molecules or ions

second messengers spread by

diffusion

what is the step after transduction

response

where might the response occur

cytosplasm / nucleus

transcription factor

regulating protein synthesis by turning on / off genes in nucleus

example of a response

regulating activity of proteins

signal transduction may result in changed in gene expression and _____

cell function

what are some effects of a signal transduction pathway problem

altering phenotype; apoptosis

how does mutations affect transduction

by modifying the ligand / receptor; changes the shape, changing the function

what can interfere with any component of the signaling pathway may activate or inhibit the pathway

chemicals

what are examples of chemicals that can activate / inhibit a pathway

neurotoxins, poisons, pesticides, and drugs

apoptosis

programmed cell death

why for apoptosis

1. protect neighboring cells from damage

2. animal development & maintenance