Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
14 Cards in this Set
- Front
- Back
|
What are the composition of membranes |
General structure is phospholipid bilayer Contain both hydrophobic and hydrophilic component Fatty acids point inward to form hydrophobic environment; hydrophilic portions remain exposed to external environment or the cytoplasm |
|
|
What are porins |
Channels for movement of hydrophilic low molecular weight substances |
|
|
What are specific porins |
LamB in e.Coli for maltose |
|
|
What is diffusion porin |
OmpF in E.Coli |
|
|
What is the cytoplasmic membrane |
Thin structure that surrounds the cell Vital barrier that separates cytoplasm from environment Highly selective permeable barrier; enables concentration of specific metabolite and excretion of waste products |
|
|
What is the membrane function |
Permeability barrier: prevent leakage of nutrients in/out Protein anchor: site of proteins promoting metabolites uptake and waste excretion Energy conservation: site of generation and dissipation of PMF |
|
|
What are the two main classes of membrane transport protein |
Carriers and channels |
|
|
What is a passive channel |
Gate: open or closed Filter: specificity continuous pore high flux rate |
|
|
What is an active channel |
Substrate binding site which has a conformational change No pore Low flux rate |
|
|
What do channels catalyse the diffusion of |
Diffusion of solutes down a concentration gradient, an energy-independent process |
|
|
What does primary active transport directly use to transport molecules against the concentration gradient across the membrane |
Metabolic energy |
|
|
What are ATP-Binding-Cassette transporters (ABC- transporters ) |
Members of a protein superfamily that is one of the largest and most ancient families with representatives in all extant phyla from prokaryotes to humans |
|
|
What is bacteria 2 type ABC transporter |
Importer only present in prokaryotes : mediate nutrients uptake Exporters : proteins, peptide, drugs, antibiotic or polysaccharides |
|
|
What is the phosphotransferase system in E. Coli |
Best studied system Moves glucose, fructose, and mannose Five proteins required Energy derived from phosphoenolpyruvate |
