Principles Biochemistry Flashcards
primary protein structure?
a sequence of amino acids
secondary protein structure and the 4 subtypes
a polypeptide backbone structure
1. alpha helix
- beta sheets 1 - can involve >1 chain
- beta sheets 2 - repeated zig zag antiparrallel structure
- triple helix - 2 left handed helical chains twisted round each other
tertiary protein structure and the 2 types
3D structure of polypeptide
1. fibrous (collagen)
globular (haemoglobin)
quaternary protein structure
special arrangement of polypeptide chains with multiple (non-protein) subunits
which RNA polymerase synthesises all mRNA
Pol II
what does Pol II require to enable transcription to occur
TFIID
what are the 3 tRNA binding sites that ribosomes have
Exit
Peptidyl
Aminoacyl
what is a cofactor
a metal ion forms a coordination centre in the enzyme
most enzymes need a cofactor to function properly
what is an apoenzyme
enzyme without co factor
what is a holoenzyme
enzyme with a co factor
what is Km
the substrate conc when the reaction rate is 1/2 maximal
what is Vmax
the max rate achieved by the system
what happens to Vmax and Km in non-competitive inhibition
Vmax is varied
Km is unchanged
what happens to Vmax and Km in competitive inhibitor
Vmax unchanged
Km varied
what does the Warburg effect suggest
instead of fully respiring in presence of adequate oxygen, cancer cells FERMENT
advantages of warburg effect
rapid energy production
rapid cell proliferation
disadvantages of warburg effect
H+ and lactase as end products
high glucose consumption, very inefficient ATP synthesis
where are all but one of the enzymes of the TCA cycle located
the matrix of the mitochondria
what is the name of the one enzyme in TCA cycle located outwith the matrix of mitochondria
succinate dehydrogenase enzyme (located in inner mitochondrial membrane)
what are the 2 stages of oxidative phosphorylation
- electron transport
2. ATP synthesis
what is the point of oxidative phosphorylation?
energy from the oxidation of NADH and FADH2 to NAD and FAD is used to pump protons from mitochondrial matrix into inter membranous space
the protons then flow back across the membrane, and this flow is used to phosphorylate ADP to ATP
what is gained from each TCA cycle
3NADH
1FADH2
2CO2
GTP
what are the 3 control points in glycolysis
- hexokinase - controls substrate entry
- phosphofructokinase - controls rate of flow
- pyruvate kinase - controls product exit
what is the role of phosphofructokinase
phosphorylates fructose 6-phosphate, which eventually becomes pyruvate
