Cell Membrane Outside of cell Inside of cell (cytoplasm) Cell membrane Proteins Protein channel...
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Transcript of Cell Membrane Outside of cell Inside of cell (cytoplasm) Cell membrane Proteins Protein channel...
Cell MembraneOutsideof cell
Insideof cell(cytoplasm)
Cellmembrane
Proteins
Proteinchannel Lipid bilayer
Carbohydratechains
Membrane structure
Semi-Permeable
Selectively Permeable
Amphipathic~ hydrophobic & hydrophilic regions
Fluid Mosaic Model
Outsideof cell
Insideof cell(cytoplasm)
Cellmembrane
Proteins
Proteinchannel Lipid bilayer
Carbohydratechains
The Structure of the Cell Membrane
Membrane structure
Phospholipids~ membrane fluidity Cholesterol~ membrane stabilization and
fluidity “Mosaic” Structure~ Integral proteins~ transmembrane proteins Peripheral proteins~ surface of membrane
proteins Membrane carbohydrates ~ cell to cell
recognition;
Random movement results in
Solution – mixture of solute and solvent
Solute – substance being dissolved
Solvent – substance dissolving solute Living Things (Universal Solvent)-Water
Membrane traffic
Passive transport~ diffusion of a substance across a biological membrane (NO ENERGY)
[] = concentration Diffusion~ the overall
movement of particles from a region of high [] to an area of low []
Osmosis~ the diffusion of water across a selectively permeable membrane
Results of Diffusion
Dynamic equilibrium Once diffusion has evenly distributed the solute
throughout the solvent; movement of particles continues with no change in []
Homeostasis Preservation of equilibrium
Diffusion depends on [] gradient
[] gradient: the difference in [] of a substance across space
Diffusion is said to move down a [] gradient
Diffusion continues until there is NO [] gradient
Ex: O2 diffuses into oxygen depleted blood
Diffusion
QuickTime™ and aCinepak decompressor
are needed to see this picture.
Small molecules like WATER, OXYGEN, AND CARBON DIOXIDE can move in and out freely.
Large molecules like PROTEINS AND CARBOHYDRATES CANNOT
Charged IONS CANNOT
Questions
Osmosis is the diffusion of _______ across a cell membrane.
Osmosis and Diffusion are both types of __________ transport.
Passive transport does or does not require energy? Small molecules can not move across freely. T or F Large molecules can move freely. T or F
Isotonic Solution
The solute outside the cell is equal in concentration to the solute in the cell.
The cell retains its shape. water moves equally in both directions
Hypotonic Solutions
Solution outside the blood cell contains a lower [] of solute than inside of the cell.
Water will diffuse in. cell will lyse (burst).
Animal cells - cytolysis. Plant cells do not burst- turgur pressure—
grocers use this idea
Hypertonic Solutions The solution outside the cell has a higher [] of solute than inside of the
cell. Water will diffuse out of the cell,
causing the cell to shrink or crenate
Why should you not salt meat before cooking?CRENATION PLASMOLYSIS
Water balance Summary Osmoregulation~
control of water balance
Hypertonic~ higher concentration of solutes
Hypotonic~ lower concentration of solutes
Isotonic~ equal concentrations of solutes
Water balance Summary
Osmoregulation~ control
in cells with cell walls:
Turgid (very firm) - Hypo
Flaccid (limp) - Iso
Plasmolysis~ Hyper plasma membrane pulls away
from cell wall
Plasmolysis Turgidity
QuickTime™ and aCinepak decompressor
are needed to see this picture.
QuickTime™ and aCinepak decompressor
are needed to see this picture.
Review Covered Passive Transport
Osmosis Does it require energy? NO!!! Diffusion Does it require energy? NO!!!
Osmosis
What is osmosis? The movement of ___________ across the
cell membrane. Is it the movement of any other substance? NO!!!!
WATER
Diffusion
Mixing of two substances by the random motion of molecules.
Molecules move from a region of high concentration to an area of low concentration.
How do other molecules cross the cell membrane???
Selective Transport Facilitated Diffusion (Another Passive Transport) Active Transport
• Protein Pumps• Endocytosis• Exocytosis
Selective Transport
There are two types of selective transport
Facilitated Diffusion• DOES NOT require the use of energy
Active Transport• DOES require the use of energy
HighConcentration
LowConcentration
CellMembrane
Glucosemolecules
Proteinchannel
Facilitated Diffusion
Facilitated Diffusion
Does facilitated diffusion require the use of energy?
NO!!!! It uses a [] gradient to transport molecules The molecules move from an area of high [] to an
area of low []
Most SUGAR molecules pass across the cell membrane by this method of transport
Carrier Proteins Carry Molecules Across the Membrane
Good Example - transport of Glucose into the Cell
Active Transport
Does active transport require the use of energy?
YES!!! It uses ATP Transports against the [] gradient. Low to High []
Sodium Potassium Pump, Endocytosis and Exocytosis
Active Transport: Sodium Potassium Pump
Move Sodium out of the cell
Move Potassium into the cell
Uses energy (ATP) Causes the protein to
change shape Move against a [] gradient
Endocytosis
During ENDOCYTOSIS the Cell Membrane folds into a POUCH (Vescicle) that Encloses the Particles.
Two Types of Endocytosis:Pinocytosis and Phagocytosis
PINOCYTOSIS ---"CELL DRINKING“—Small Particles
PHAGOCYTOSIS---- "CELL EATING“-Large Particles
Exocytosis
EXOCYTOSIS is the opposite OR reverse of ENDOCYTOSIS.
EXOCYTOSIS, wastes and cell products leave the cell.
Specialized Transport Summary Transport proteins Facilitated diffusion~
passage of molecules and ions with transport proteins across a membrane down the [] gradient
Active transport~ movement of a substance against its [] gradient with the help of cellular energy