L7 energ prod from lip Flashcards
LO2: desc maj energ stores in 70 kg man.
-TAG 15kg, 600000kJ. req 11000kJ/d. glycogen 0.4kg, 4000kJ. musc prot 6kg, 100000kJ. -135kg man: TAG 80kg, 3000000kJ. need lose 220d energ while still eating. glycogen 0.4kg. musc prot 6kg.
LO3: desc how diet TAG proc to prod energ.
-TAG=glycerol backb esther bond to phob FA/acyl chains. v reduced, 2H each C. esterific forms TAG and water. lipolysis breaks. phob, stored anhyd in adip. store of FA and glycerol used in exerc, starvat, preg. stor/mobil horm contr, insulin incr, glucagon/adren/cortisol/gf/thyroxine decr.
-S1: TAG to FA and glycerol in GIT uses atp, prods NADH. glycerol to blood to liver. FA to chylomicron in GIT to blood via lymphat to adip then back to blood as FA-albumin then to consumer tiss where oxid for energ. need mito, not x BBB.
FA re-esterif to faCoA then esterif to TAG using glycerol 1P from glycol. so low gluc extracell= FA rel as alt fuel as orev resynth TAG so FA build in tiss and rel to blood.
FA 16-20C tot. sat non essen. sat 1-4 C=C. cert polyunsat essen.
-S2: FA activ by link to CoA outs mito, use ATP. carnitine shutt into mito- inhib by malonyl CoA, defects= exerc intol and lip droplets in musc.
beta oxid: mito. cyc through seq oxid reacs, 2C rem each time and form aCoA. req O. no direc ATP synth. all intermeds linked to CoA. more energ der than gluc oxid. prods NADH and FADH2. not occ in brain, RBC, WBC.
LO4: cent role aCoA in metab.
-main converg pt for catab paths=activ 2C. CH3CO to CoA via S at= high energ bond. conts VitB.
aCoA to FA or CO2 or HMG which then forms ketone bods or chol for ster horm.
aCoA prod by catab FA, sug, alc, some aa. can be oxid TCA. imp intermed lip bios-maj in liver, some adip. most can be synth.
LO5: expl how, why, when ketone bods formed.
3 ketone bods prod by bod:
-acetoacetate liver from aCoA.
-acetone-spont decarboxyl acetoacetate.
-beta hydroxybutyrate- more reduc from of acetoacetate, liver form aCoA.
norm plasma ket bod under 1mM. starvat 2-10mM=physiol ketosis. untreat T1DM= over 10mM= pathol ketosis. glucagon and adren. acetone fruity breath.
-synth by liver in mito:
HMG CoA reductase- HMG CoA to mevalonat which forms chol. inhib by statins. ACTIV by insulin. INHIB by glucagon so HMG CoA forms ketone bods instead. inculin activs lyase which convs HMG CoA to acetoacetate.
-ketone bod synth reqs:
FA av for oxid in liv foll excess lipolysis in adip-supp S.
plasma insulin/glucag low us due to decr unsilun=activ lyase and inhib reductase.
can be used by all tiss with mito incl CNS. rate insulin use propor to plasma conc. are conv to aCoA which is oxid by TCA.
-contr ket bod prod in liv.
aCoA from beta oxid can ent TCA or form ketone bods.
NADH inhib iscitrate DH and aKG DH=build up CoA cant ent TCA so diverted to ket bod.
-metab ketone bods- made in liver to blood to consumer tiss eg musc where they allow TCA by recyc CoA from succinyl CoA to form aCoA to re ent cyc.
- ketone bods spare gluc in starvat/diab-
early starvat- keone bod alone. TAG to FA in adip. FA to liver where conv to ket bods. to musc where used for aCoA format for TCA H2o and CO2 form, prevs gluc util.
prolong startvat- need prot too. prot to aa in musc. aa to liver gluconeogenesis to gluc. to brain for metab. need 5mM gluc for brain/RBC.
-ketone bods- water sol allow high plasma conc and ketonuria above renal thresh. alt S. acetoacetate and beta hb strong organ ac cause ketoacidosis, decr blood pH. acetone volatile excret via lung.
LO1: desc classes of lip.
-struc div. insol phob. most cont C, H, O, Plip also P, N. more reduced than carb.
-FA derivs- FA fuel. TAG stor and insul. Plip in mem and plasma lipoprot, lip transf in packs cov in Plip. eicosanoids loc meds cig btw cells=coord tiss resp.
hydroxymethyl glutamic ac derivs- ketone bods C4 water sol fuel der from HMG imp in starvat. chol C27 mems and ster horm synth, when lot ketone bods div to prod chol, can form esthers/bile ac. chol esthers- chol stor. bile ac and salt C24-lip dig.
Vits- ADEK.
