Topic 4 Flashcards
Describe ABC transporters.
they are hydrophobic proteins with a nucleotide binding protein and membrane channel; when solute is present, ATP is hydrolyzed to give energy to open membrane to let solute through
How does the cytoplasmic membrane adjust itself at low temperatures?
it increases the amount of unsaturated phospholipids to maintain flexibility
What is facilitated diffusion?
does not require energy and uses a channel membrane protein to transport substances down a concentration gradient
What is a permease?
a substrate-specific carrier protein that can can carry the substrate with or against concentration gradient
What is conjugation?
direct cell-to-cell transfer through pili
What is transformation?
taking up bacterial DNA released from dead cells in the environment
What is transduction?
mediated by bacteriophages as they infect and replicate in bacterial cells and exit to infect another cell
What are the 3 main functions of the cytoplasmic membrane?
permeable barrier, protein anchor, and energy conservation
What is the difference in the phospholipids of archaea vs bacteria/eukarya?
archaea - have phytanyl chains and ether bond
bacteria/ eukarya - have fatty acid chains and ester bond
What effects do saturated vs. unsaturated lipids have on the CM?
unsaturated will melt at low temperatures and they increase fluidity
saturated will melt at high temps and they increase rigidity
What is the function of hopanoids in the CM?
increase stability
What is simple diffusion?
small uncharged molecules moving down the concentration gradient
What is active transport and the two types?
movement of molecules from low [ ] to high
symporters - move two molecules in the same direction
antiporters - move two molecules in opposite directions
What occurs during osmosis in a hypertonic solution?
higher solute [ ] outside of cell so water moves out of cell
What occurs during osmosis in a hypotonic solution?
lower solute [ ] outside of cell so water movies into the cell
