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

Osmosis

Osmosis~ the diffusion of water across a selectively permeable membrane

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

Three Different Types of Solutions

Isotonic Solution

Hypotonic Solution

Hypertonic Solution

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

Cells in a Hypotonic Solution

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

Cells in a Hypertonic Solution

In what type of solution would these cells be found?

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.

Other Ways to Transport Molecules Across the

Plasma Membrane

Selective Transport

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

Molecule tobe carried

Moleculebeing carried

Energy

Active Transport

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

Sodium Potassium Pump

Bulk Transport-Active

Endocytosis Pinocytosis Phagocytosis

Exocytosis

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

Treatments

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

Elaborate

Cell Membrane Bubbles Cellular Transport Flow Chart