ch 6. biological membranes (part I and II)

membrane composition (fluid moasic) and transport of small molecules

major component of the membrane

phospsliids

what is the fluid mosaic model

The membranes are not rigid static structures. They are fluid and an integrated mosaic of several components such as lipids, proteins and carbohydrates.

what is the major force binding the membrane

the hydrophobic interactions and the other membrane lipds and hydriphbic residues of the membrane proteins

what forces operate between the hydrocarbn chains of closey packed plipids

van der waals

what influnces the fludiity of the membrane

temerapte, membrane composition (saturated vs unsaturated), and cholestrol

relationship between temperature and fludity

direct T ↑ F↑

relationship between fluidity and fatty acids

saturated fatty acids make the membrane less fluid aka rigid

how many sides does the membrane have?

2: cytoplasmic side and external side. serpate is important for enxyme function, receptios, and transport proteins

the cytoplasmic side is interconnected to

the cyctoskeleton elements for support and realtive positiong of membrane components

functions of cell membrane

boundary of cell and its organelles, facilitates transports, biochemical reactions, critical for rsponse to environmental changes, help signal t ransduction, cell to cell communction, maintain cell environments

small molecule size

less than 100 Daltons

medium molecule size

100- 1000 Daltons

large or macromolecule size

1000 Daltions or more

simple diffsuion occurs where?

though the phosphlipid part of the bilayer

what molecules can pass through using simple diffusion

small molecules: hydrophobic molecules, hydrocarbons, steriods, non=polar molecules (ex: O2 and CO2)

what is facilitated diffusion

membrane proteins facilitate the transport of charged ions (ion channels) and molecules across the membrane

how many types of faciliated transport is there

3: uniport, symport, antiport