lecture 3.2

What structure defines the existence of a cell

The cell membrane

What does a phospholipid consist of?

Glycerol with ester links to two fatty acids in phosphoryl head group

What are leaflets?

The two layers is phospholipids in the bilayer

What do membranes consist of?

Equal parts of phospholipids and proteins

what are the reinforcing agents in eukaryotic membranes

sterols (e.g. cholestrol)

what are the reinforcement agents in bacteria

hopanoids/hopanes

what is the function of planar molecules in membranes

to fill gaps between hydrocarbon chains

which domain has the most extreme variation in phospholipid side-chain structures

archaea

what are the functions of membrane proteins

- Structural support

- Transport and Secretion

- Detection of environmental signals

- Energy generation

what do membrane proteins have in order to lock in the membrane

hydrophilic and hydrophobic regions

what does the cell membrane act as

semipermeable barrier for selective transport

diffusion

small uncharged molecules like O2 and CO2 easily permeate the membrane

osmosis

water diffuse across the membrane

protein transporters

Polar molecules and charged molecules require transport

passive transport

molecules move along their concentration gradient

active transport

molecules move against their concentration gradient

what does protein transporters require?

energy