Chapter 8: Biological Membrane

cell plasma membrane

semipermeable phospholipid bilayer

Lipid Rafts

collection similar lipids with or without associated protein that serve as attachment points for other biomolecules, serve roles in signaling

Flippases

Assist in transition or flip between layers

Fatty acid

Carboxylic acid contain hydrocarbon chain and terminal carboxyl group

Triaglycerol

Storage lipid involved in human metabolic processes

Unsatturated fatty acid

Have one or more double bond, exist in liquid form at room temp

Saturated fatty acid

Main component animal fat and tend to exist as solid in room temp, found in processed food and less healthy

Inducible system

repressor bonded tightly to operator system and acts as roadblock

Negative control

binding protein reduces transcritpional activity

Repressible system

allows constant production of protein product

Postivie control

which bindng of molecule increase transcription of gene

Transcription factors

transcription activating proteins that search the DNA looking for specific DNA binding motifs

DNA binding domain

bidns to a specific nucleotide sequence in promoter region or to a DNA response element

Activation Domain

allows for binding several transcription factors and other important regulatory protein

Heterochromatin

tightly coiled DNA inacessible to transcritipn inactive

Euchromatin

looser transcription machinary can acess gene, active

Acetylation of Histone

decrease plus charge on lysine residues and weaken interaction of histone with DNA resulting in an open chromatin conformation that allows for easier acess fo transcriptional machinary to DNA

DNA methylases

add methyl group to cytosine and adenine nucleotdie

sphingolipids

do not contain glycerol, contain hydrophilic region of two fatty acid

Waxes

class fo lipids extremely hydrophobic rarely found in cell membrane of animal but found in those of plants

Cell Cell junction

form cohesive layer via intercellular junctions, provide direct pathways of communication between neighboring cells or between cells of extracellular matrix

Gap Junction

allow direct cell cell communication often found in small bunches together

Tight Junction

prevent solutes leaking into space between cell via paracellular route

Desmosome

bind adjacent cells by anchoring to their cytoskeleton

Hemidesomsome

attach epithlial cells to underlying structures

What proceeds through passive transport

spontaneous processes

What proceeds through active transport

nonspontaneous transport

simple diffusion

substrates move down their concentration gradient directly across the membranes

membraen potential, Vm

difference in electrical potential across cell membranes

Nernst Equation

E=RT/ZF= ln ([ion]outside/[ion]inside)