honors biology cellular transport. diffusion the net movement of particles from an area of high...
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Honors BiologyHonors BiologyCellular TransportCellular Transport
DiffusionDiffusion
The net movement of particles from an area of high concentration to an area of low concentration
High concentration Low concentration
Equal distribution
DiffusionDiffusion
Movement goes with the concentration gradient– From areas of high concentration to areas
of low concentration
OsmosisOsmosis
Diffusion of water through a selectively permeable membrane
Goes with the concentration gradient
OsmosisOsmosis
Weaksolution
Strongsolution
WATER
(Lots of water molecules) (Few water molecules)
Selectively permeablemembrane
Weaksolution
Strongsolution
Membraneallows
water topass but
not solutes
Solutions with equalconcentrations
OsmosisOsmosis
Special terms for referring to strong or weak solutions
OsmosisOsmosis
Special terms for referring to strong or weak solutions– Isotonic: two solutions with equal
concentrations of solutes
OsmosisOsmosis
Special terms for referring to strong or weak solutions– Isotonic: two solutions with equal
concentrations of solutes– Hypertonic: solution with high concentration
of solutes (strong solution)
OsmosisOsmosis
Special terms for referring to strong or weak solutions– Isotonic: two solutions with equal
concentrations of solutes– Hypertonic: solution with high concentration
of solutes (strong solution)– Hypotonic: solution with low concentration
of solutes (weak solution)
OsmosisOsmosis
Hypotonic HypertonicWATER
When does diffusion/osmosis stop?When does diffusion/osmosis stop?
Never! When it reaches a homeostatic balance equal numbers of molecules are
moving in both directions!
Turgor PressureTurgor Pressure
The pressure inside a cellMaintained via osmosis
Turgor PressureTurgor Pressure
Plasmolysis
Contractile VacuolesContractile Vacuoles
Lysis
Cellular TransportCellular Transport
Passive: goes with concentration gradient
Active: goes against concentration gradient
Cellular TransportCellular Transport
PassiveActiveEndo- and Exocytosis
Cellular TransportCellular Transport
Passive– Simple diffusion through the lipid bilayer– Simple diffusion through an ion channel– Facilitated diffusion
ActiveEndo- and Exocytosis
Passive TransportPassive Transport
Simple diffusion through the lipid bilayerSimple diffusion through an ion channelFacilitated diffusion
Simple diffusion through the lipid Simple diffusion through the lipid bilayerbilayerSmall, non-polar molecules
– O2 and CO2
OsmosisGoes with concentration gradient
Passive TransportPassive Transport
Simple diffusion through the lipid bilayerSimple diffusion through an ion channelFacilitated diffusion
Simple diffusion through an ion Simple diffusion through an ion channelchannelIons are highly polar and cannot pass
through the lipid bilayerIons are critical to cell functioning
– Na+, K+, Ca+, and Cl-
Simple diffusion through an ion Simple diffusion through an ion channelchannelPass readily through a water-filled pore
formed by an integral membrane protein
Simple diffusion through an ion Simple diffusion through an ion channelchannelMovement is bi-directionalChannels are specialized for a single ion Goes with concentration gradient
Passive TransportPassive Transport
Simple diffusion through the lipid bilayerSimple diffusion through an ion channelFacilitated diffusion
Facilitated DiffusionFacilitated Diffusion
Diffusion is aided by a carrier protein (integral membrane protein)
Facilitated DiffusionFacilitated Diffusion
Molecule to be transported physically binds to the carrier protein on one side of the membrane
Protein undergoes a conformational change that does not require energy
Molecule is released on the other side of the membrane
Facilitated DiffusionFacilitated Diffusion
Molecule is attracted to a specific carrier protein
Facilitated DiffusionFacilitated Diffusion
Molecule binds to carrier protein
Facilitated DiffusionFacilitated Diffusion
Carrier protein undergoes conformational change and releases molecule on other
side of membrane
Facilitated DiffusionFacilitated Diffusion
Movement is bi-directionalCarrier proteins are specialized for a
single ion or moleculeGoes with concentration gradientPassive process
Cellular TransportCellular Transport
PassiveActiveEndo- and Exocytosis
Active TransportActive Transport
Similar to facilitated diffusion– Molecule to be transported physically binds
to the carrier protein on one side of the membrane and is released on the other side of the membrane via a shape change of the protein
Active TransportActive Transport
Goes against concentration gradientRequires energy input from the cell
Active TransportActive Transport
Active TransportActive Transport
Active TransportActive Transport
Bi-directionalCarrier proteins are specialized to move
a single substance
Active TransportActive Transport
Sodium-Potassium (Na-K) PumpCotransportCountertransportProton Pump (Next chapter)
NaNa++ - K - K++ Pump Pump
Cell needs low Na+ and high K+ relative to external environment
Ions are “pumped” into and out of the cell via an integral membrane protein
Na+ concentration becomes form of stored energy for cotransport
CotransportCotransport
Na+ is pumped into cell with concentration gradient
Simultaneously sugar or amino acid is pumped into cell against concentration gradient
CountertransportCountertransport
Na+ is pumped into cell with the concentration gradient
Ca+ or H+ is pumped into cell against the concentration gradient
Cellular TransportCellular Transport
PassiveActiveEndo- and Exocytosis
Endo- and ExocytosisEndo- and Exocytosis
Used to move large amounts of materials into or out of a cell quickly
Requires energy
EndocytosisEndocytosis
Cell consumes large molecules or other cells
Cytoskeleton extends plasma membrane outward toward particle, encircles the it, and contracts membrane back inwards, engulfing particle
EndocytosisEndocytosis
2 types– Phagocytosis– Pinocytosis
EndocytosisEndocytosis
Phagocytosis: “Cell eating”– Cell takes in solid particles
EndocytosisEndocytosis
Pinocytosis: “Cell drinking”– Cell takes in liquid materials
ExocytosisExocytosis
Cell excretes large wastesMechanism for releasing hormones