L3A: Rxn Types that Transform Energy in Metabolism & L3B: Electron Carriers Flashcards
what does oxidation form basis of
catabolism
what does reduction form basis of
anabolism
what does delta G’0 directly relate to
number of electrons transferred in a reaction
metabolic energy circuit - aerobic metabolism
- electrons flow to intermediate biomolecules
- electron carriers to final electron acceptor, O2
- resultant EMF (electron motive force) provides energy to molecular energy transducers
4 ways of e- transfer
- directly
- as hydrogen atoms
- as hydride ions
- by direct combination of organic reductants w/ O2
what are the major e- carriers in metabolism
NAD, NADP, FAD, FMN
what are NAD & NADP
soluble e- carriers that work w enzymes to carry e-s from one chem species to another
what does NAD function in
Catabolism
what does NADP function in
Anabolism
what are NAD & NADP derived from
the vitamin niacin (Vit B3)
dietary sources of niacin
tuna
salmon
halibut
venison
asparagus
what is a niacin deficiency called and what are the 3 symptoms
deficiency causes pellagra.
symptoms: dermatitis, diarrhea, dementia
what structure in NAD/NADP accepts the hydride ion
the nicotinamide ring
what is a hydride ion
2 electrons and 1 proton
what enzymes use NAD as coenzymes
dehydrogenases & hydrogenases
steps in a reduced substrate donating electrons
- reduced substrate donates electrons to NAD+ using a dehydrogenase enzyme
- the substrate has been oxidised
- NAD had been reduced & carries electrons to another biomolecule
OIL RIG
rxn of NAD & alcohol dehydrogenase (ADH)
CH3CH2OH + NAD+ —-> CH3CHO + NADH + H+
(in presence of ADH)
oxidises alcohols & allows alcohol consumption
what does FAD stand for
flavin adenine dinucleotide
what does FMN stand for
flavin mononucleotide
what are FAD and FMN derived from
riboflavin (vit B2)
dietary sources of riboflavin
milk
cheese
beans
leafy greens
what kind of dehydrogenases do FAD and FMN covalently bind to
dehydrogenases called flavoproteins
what structure in FAD & FMN accepts electron and in what form
the isoalloxazine ring accepts 1 or 2 electrons in the form of hydrogen atoms
formula for addition of one and 2 e-s to FAD
- FAD + H+ —> FADH
- FAD + 2H+ —-> FADH2
