Week 1 - Plasma Membrane & Transport Flashcards
Describe the self helmet of the plasma membrane
- Rearrangement
- Infold - Vesicle formation
What are the three types of cell division?
Mitosis, meiosis, binary fission
What three reasons are given to support that all organisms are derived from a single primordial cell?
- Resemblance among living cells
- Common cell components
- Fossil evidence
What are the three shapes of prokaryotes?
Spherical - coccus
Rod - bacillus, coccobacillus
Spiral - vibe, spirillum, spirochete
What are monomorphic and pleomorphic?
Mono = one form Pleo = variable in size, shape and staining
What are most bacteria cell walls made from?
Peptidoglycan, ligands for cell adherence
Describe Gram Staining, positive and negative
Anthrax gram stain -
Positive - shows thick peptidoglycan cell wall - violet
Negative - shows thin peptidoglycan cell wall - red/pink
Describe horizontal gene transfer in prokaryotes and why is has a negative impact
- Pilus connects donor and recipient
- DNA polymerase used to polymerase new F-Plasmid transferred through pilus via relaxasome transferasome
Significant cause of increase in drug resistance
What is a fimbriae?
Attachment pilus
Describe three lipid types
Phospholipids
Glycolipids
Sterols
Name the five common phospholipids
Phosphoglycerides Phosphoatdylcholine Phosphatidylethanolamine Phosphatidylserine Phosphatidylinositol
Describe a glycosphingo lipid
Glycerol + Sphingosine base
Describe blood group antigens
Glycolipids, change in sugars on the RBC dependent on enzymes
O - Fucose, Galactose x2 and N acetyl-glucosamine
A - N acetyl-galactosamine, N acetyl-glucosamine, Galactose x2, fucose
B - Galactose x3, Fucose, N acetyl-glucosamine
AB - all of A + B
Describe phospholipid fluidity
- Rotation around long axis
- lateral diffusion - same monolayer
- transverse diffusion ‘flip flop’ from one monolayer to another (very rare) - energetically unfavourable
Describe membrane fluidity with respect to cholesterol
Cholesterol buffers fluidity and allows membrane to be fluid over a wider temperature range
- Allows more space to be formed between phospholipids therefore encouraging more movement
What are lipid rafts?
Clusters of lipids + proteins within membrane making the membrane less fluid
What are the three classes of membrane proteins?
Integral - embedded - helical
Peripheral - inside/outside
Lipid anchored - surface membrane
What is the resting membrane potential range?
-50mv to -90mv
What ions are in higher conc extracellular?
Na+ (150) CL- (108)
What ions are in higher conc intracellular?
K+ (150) Anions (65) Phosphate
What are the four transport mechanisms?
Diffusion
Facilitated Diffusion
Primary active transport
Secondary active transport
Describe Transport Proteins
All integral with 12 transmembrane segments
How are carrier proteins categorised + describe
Uniport - single solute
Symport - 2 solutes simultaneously
Antiport - 2 solutes opposite directions
Describe channel proteins
Hydrophilic transmembrane channel
ion channels
Porins
Aqua Porins
