Cell Membrane andCell Membrane andCell TransportCell Transport

Molecular Structure ofMolecular Structure ofthe Cell Membranethe Cell Membrane

Phospholipid MoleculePhospholipid Molecule

Hydrophillic head (water loving)Hydrophillic head (water loving)

Hydrophobic tail (water hating)Hydrophobic tail (water hating)

Profile: Plasma MembraneProfile: Plasma Membrane

Factors Affecting PermeabilityFactors Affecting Permeability

1.1. Molecular size of particlesMolecular size of particles2.2. Electrical charge of particlesElectrical charge of particles3.3. Solubility of substance in water moleculesSolubility of substance in water molecules

Molecular sizeMolecular size

The cell membrane is generally The cell membrane is generally permeable to small molecules:permeable to small molecules:

i.i. carbon dioxide (COcarbon dioxide (CO22))

ii.ii. water (Hwater (H22O)O)

iii.iii. glucose (Cglucose (C66HH1212OO66))

2. Electrical Charge2. Electrical Charge

Electrical charge on the atom or molecule Electrical charge on the atom or molecule affects the movement of particles.affects the movement of particles.

PositiveNegative

Na+

Cl-

Solubility of substance in waterSolubility of substance in water

Refer to Chemistry Periodic Table for Refer to Chemistry Periodic Table for Solubility of various monatomic and Solubility of various monatomic and polyatomic atoms/moleculespolyatomic atoms/molecules

DIFFUSION - Conditions for theDIFFUSION - Conditions for themovement of particlesmovement of particles

Concentration of solutes (i.e. sugar) is Concentration of solutes (i.e. sugar) is either HIGHER or LOWER.either HIGHER or LOWER.

AssignmentAssignment

Define the following words:Define the following words:

Passive transportPassive transport Brownian motionBrownian motion DiffusionDiffusion OsmosisOsmosis Concentration gradientConcentration gradient

7.7. EquilibriumEquilibrium8.8. HomeostasisHomeostasis9.9. Hypo/iso/hypertonicHypo/iso/hypertonic10.10.Active transportActive transport11.11.PinocytosisPinocytosis12.12.PhagocytosisPhagocytosis