Cell Biology Flashcards
What interactions hold proteins embedded in the lipid bilayer ?
Non-covalent
What factors affect the packing/ fluidity of hydrophobic tails?
cis double bond (saturation)
tail length
What organisms DO NOT have cholesterol for stability ?
bacteria
Plants have sterol
What does cholesterol do when the temp is low?
Low temp = PL move less, packed tighter
Cholesterol increases spacing of HC and fluidity
How to lipid rafts move?
They move laterally
Formed by mem with lots of cholesterol and sphingolipids
Used for cell signalling
Uptake of extracellular mol (endocytosis)
Why do we need membranes?
Compartmentalisation Allow ionic gradients Selected movement of mols Generate electrical signals Euk= enclose organelles Embedded proteins sense change in external
What are some roles of the endoplasmic reticulum ?
Protein + lipid synthesis
Ca2+ store
storage of proteins
Protein glycosylation
What is the role of the Golgi?
Carb synthesis
glycosylation
packages proteins
What is an example of a mobile organelle?
Mitochondria Associate with microtubules
What are the A, P, E sites on a ribosome ?
A= incoming aminoacyl tRNA P= peptidyl transferase E= exit of deacylated RNA
Describe the features of peroisomes
Single membrane Contain oxidative enzymes (high conc=crystalline core ) Use molecular o2 to remove H Produce hydrogen peroxide Break down fatty acids C- terminal ser-lys-leu signal
Describe features of a lysosome
Soluble hydrolytic enzymes Acid hydrolase (acidic enviro) Phagocytosis, autophagy,
How does a lysosome not digest itself?
Highly glycosylated protein
