Cell Biology and Signalling Flashcards
What are bacterial cell walls made from?
Peptidoglycan
Which has an antagonistic action to adenylate cyclase?
Phosphodiesterase
α helices and β sheets are formed by which type of bonding?
Hydrogen
What is KM a measure of?
Enzyme performance
Where does ATP respiration occur in:
a) prokaryotes
b) eukaryotes
a) Cell membrane
b) Mitochondria
What 3 filaments is the cytoskeleton made up of?
Actin
Microtubules
Intermediate filaments
3 functions of S.E.R?
N-linked glycosylation
Detoxification of xenobiotics
Biosynthesis of membrane lipids + steroids
2 functions of R.E.R?
Proteins for secretion/insertion go to cell membrane Proteins folded - cys-cys bridge formed
3 functions of Golgi apparatus?
Glycosylation of O-linked carbs + lipids
Synthesise lysosomes
Synthesise + package material to be secreted, direct proteins to correct compartments
4 functions of peroxisomes?
Detoxification of toxins, alcohols. FAs
Phospholipid synthesis
Oxidation of VLCFA
Enzymes which generate and degrade H2O2
What causes Zellweger syndrome?
Inherited absence of peroxisomes due to defects in targeting
What causes adrenoleukodystrophy (ALD)?
Affects protein that imports VLCFA into peroxisomes
What is autophagy?
Organelle turnover/replacement
Myoclonic epilepsy with Ragged Red Fibre (MERRF Syndrome)?
Mutation of mitichondrial gene for tRNA -lys
Hutchinson-Gilford Progeria?
Mutation in lamin-A prt of nuclear envelope
Distorted shape of nucleus (blebbed)
Production of unique progerin protein
Tay-Sachs disease?
Mutation of lysosomal hexosaminidase- A enzyme
Causes accumulation of ganglioside that is neurotoxis
What are operons (in bact)?
Functining unit of DNA containing cluster of genes under control of a single promoter
What are the 6 types of enzymes and their functions?
Oxidoreductases - catalyse transfer of H + electrons
Transferases - catalyse transfer of functional groupss between molecules
Lyases - cleavage of C-C, C-O, C-N, addition to/formation of double bonds
Hydrolases - cleavage of bonds by addition of H2O
Isomerases - transfer of functional groups within same molecule
Ligases - catalyse formation of new covalent bonds using ATP, repair DNA breakage
Soluble vs Membrane Protein?
Soluble - present in cytosol, hydrophobic core and hydrophilic surface
Membrane - embedded within membrane, hydrophobic surface
What type of enzyme is chymotrypsin and what does it affect?
Hysrolase
Cleaves peptide bond on carboxyl side of tryptophan, tyrosine, phenylalanine + large hydrophobic residues e.g. Methionine
What makes up chymotrypsin catalytic triade?
Serine
Histidine
Arginine
3 assumptions about Michaelis-Menton plot?
[S]»[E]
[ES] x change with time (steady-state0 - made at same rate as broken down
Initial velocities used, [product] small, bakc reaction of P to S ignored
What is Michaelis-Menton equation?
V0 = Vmax[S]/Km + [S]
