Prokaryote Cell Biology Flashcards
What do bacterial membranes consist of?
Saturated and monounsaturated fatty acids
Do no normally contain sterols like cholesterol
Why are prokaryotes useful for agriculture?
Legumes: bacteria form root nodules
Nitrogen fixation for plants
Nutrient cycling
Animal husbandry: rumen - breaking down cellulose
What are some typical bacteria shapes?
Rod
Coccus
Spirillum
What is the typical size of a bacteria?
2 micro m - 50 micro m
What are the two components making up cell membranes?
Hydrophilic head: polar, “likes” water
Hydrophobic tail: non-polar, can be kinked by double bonds
What is a saturated fatty acid?
No double bonds
What is a monounsaturated fatty acid?
Has a single double bond
How are bacterial cell membranes fluid and dynamic?
Lipids can move, flip and be modified
Lateral movement: 10^7 times per second
Flip-flop: once a month
Remember bacterial membranes can have things embedded in them!
Remember bacterial membranes can have things embedded in them! e.g. proteins
What is the issue with a double membrane and how is this dealt with?
Membranes are difficult to move things across
So the inner membrane is typically quite porous and easier for substances to pass through
Outer membrane has more channels, etc to regulate movement of substances
What are transmembrane proteins?
Go through both membranes in a double membrane
Describe an archaeal membrane.
Hydrophobic side chains are composed of isoprene
Composed of branched hydrocarbon chains
Attached to glycerol by ether linkages
Glycerol is chiral
What is the role of the cell membrane?
Permeability barrier
Protein anchor
Energy production and conservation
What channel does water come in and out of the cell via?
Aquaporin
Open most of the time to allow small amount of water molecules through
Always some moving in and out
Can open wide to allow more through
Why are there proteins on the outside of cells?
To recognise other cells
