BellworkBellwork►What happens to an animal cell when What happens to an animal cell when

it is in a hypotonic solution?it is in a hypotonic solution?►What happens to an animal cell when What happens to an animal cell when

it is in hypertonic solution? What about it is in hypertonic solution? What about a plant cell?a plant cell?

ReviewReview

►Onion cell plasmolysis

More ReviewMore Review

Facilitated diffusionFacilitated diffusion

Active transport and Active transport and Cell signalingCell signaling

Active Transport► Uses energy to Uses energy to

pump molecules pump molecules against their against their concentration concentration gradientgradient

►Where do you think Where do you think they get this they get this energy?energy?

► ATP!!!ATP!!!

Electrical gradientElectrical gradient► Uneven distribution Uneven distribution

of ions gives it an of ions gives it an electrical gradient electrical gradient (neg inside the cell, (neg inside the cell, pos outside the cell)pos outside the cell)

CotransportCotransport► A solute flows with A solute flows with

another substance another substance that is diffusing that is diffusing across the across the membranemembrane

Endocytosis - Endocytosis - ►Phagocytosis – Phagocytosis –

Cell eatingCell eating►Pinocytosis – cell Pinocytosis – cell

drinkingdrinking►Receptor-Receptor-

Mediated Mediated EndocytosisEndocytosis

Check for understandingCheck for understanding►Compare and contrast active and Compare and contrast active and

passive transportpassive transport

Cell signaling Cell signaling Epinephrine – increases heart Epinephrine – increases heart

rate, dilates blood vessels, rate, dilates blood vessels, dilates pupils, elevates blood dilates pupils, elevates blood

sugarsugar

Assign one to each group Assign one to each group membermember

►Communication by direct contactCommunication by direct contact Cell junctionsCell junctions Cell-cell recognitionCell-cell recognition

►Local signalingLocal signaling Paracrine Paracrine Synaptic signalingSynaptic signaling

►Long DistanceLong Distance HormonesHormones Nervous systemNervous system

What is the relevance of cell What is the relevance of cell signalingsignaling►Another example - Another example - CaffeineCaffeine

Three stages of cell signalingThree stages of cell signaling

ReceptionReception► Reception on the Reception on the

plasma membrane plasma membrane (3 main types)(3 main types) G protein coupled G protein coupled

receptorsreceptors Receptor tyrosine Receptor tyrosine

kinasekinase Ion channel receptorsIon channel receptors

► Intracellular Intracellular receptorsreceptors

Intracellular receptor

Reception in epinephrineReception in epinephrineG protein coupled receptors

TransductionTransduction► Signal cascade – Signal cascade –

one molecule one molecule activates the next activates the next (usually by (usually by phosphorylating it)phosphorylating it)

Transduction in epinephrineTransduction in epinephrine

ResponseResponse► Response can be…Response can be…

a gene being a gene being expressed (making a expressed (making a proteinprotein

Replication of the cellReplication of the cell Activation of an Activation of an

enzymeenzyme Change in cell shapeChange in cell shape Programmed cell Programmed cell

deathdeath And much more!And much more!

Response in Response in epinephrineepinephrine

Cancer can be caused by an Cancer can be caused by an error in signal molecules or error in signal molecules or

transduction pathwaystransduction pathways