anaerobic metabolism- regulation of glycolysis and the TCA finish Flashcards
what is the equation for the breakdown of glucose
C6H12O6+O2+ADP—> CO2+H20+ATP
what do we call a molecule that loses electrons
oxidised
what do we call a molecule that gains electrons
reduced
what is an electron carrier
it is a molecule which transports electrons during cellular respiration
how do electron carriers work
they can store energy until it is needed
what are the two examples of electron carriers
NAD
FAD
WHAT DOES FAD stand for
flavin adenine dinucleotide
what does NAD stand for
nicotinamide adenine dinucleotide
what is the equation when NAD is reduced
NAD+2H–> NADH+H+
what is the equation when FAD is reduced
FAD +2H—> FADH2
how is pyruvate converted into acetyl coA
decarboxylation and then NAD reduced to NADH
how many NADH do we get in the whole stage of the link reaction
2 as one per molecule of pyruvate
what are the end products of glycolysis
2 pyruvate
2 ATP
what are the end products of the TCA cycle per pyruvate molecule
3 NADH
FADH2
ATP
per pyruvate
what are the stages of the fermentation of glucose
glucose to pyruvate and then to ethanol +C02
what type of process is the fermentation process
it is anaerobic and does not go through the TCA or oxidative phosphorylation
how is pyruvate converted to acetaldehyde
by the enzyme pyruvate decarboxylase which releases C02 as well
how do we convert acetaldehyde to ethanol
with the enzyme alcohol dehydrogenase
what are the steps to convert pyruvate into ethanol
pyruvate undergoes decarboxylation by pyruvate decarboxylase and forms ACETALDEHYDE this under goes dehydrogenation via acetyl dehydrogenase to form ethanol
where does fermentation occur
in the cytosol
what do we also produce during fermentation
CO2 and oxidised NAD
why is this reaction essential
as it regenerates oxidised NAD which is used during glycolysis
what are some situations during fermentation which causes yeast to die
too much ethanol OR C02
what occurs in the fermentation of skeletal muscle
there is reduced glycolysis and TCA cycles as we run out of oxidised NAD
during periods of high intensity
what happens in our msucles
pyruvate forms lactate via lactate dehydrogenase enzyme and NAD is deoxidised
what do we feel during periods of high intensity
pain in our muscles due to lactic acid buildup
what other sugars are metabolised via glycolysis
galactose
fructose in adipose tissue
fructose in the liver
what is galactose converted into
glucose 6p
what is fructose in the adipose tissue converted into
fructose 6p
what is fructose in the liver converted into
DHAP then GAP
which enzyme breaks down lactose
lactase
what type of enzyme is lactase
brush border enzyme
what is lactase broken down into
galactose and glucose
what are the symptoms of lactose intolerance
farting diarrhoea bloating stomach cramps rumbling feeling sick
what is galactosemia
inherited autosomal recessive disorder and can be screened at birth
what can galactosemia cause
enlargement of the liver CNS failure
why do people get galactosemia
deficiency of galactose phosphate uridyl transferase
how do we regulate glycolysis and the TCA cycle
changes in physiological and environmental circumstances
metabolism is constantly monitored
genetic regulation
how can metabolism and the TCA cycle be regulated
by genetic regulation which controls the amount of enzymes in the cell and the amount of enzyme degradation
what four things can happen to the enzyme
association with regulatory protein
sequestration
allosteric regulation
covalent modification
what is allostatic regulation of enzymes
an inhibitor binds to the enzyme and prevents the working and changes the shape of the enzyme
what is involved in covalent modifications of the enzyme
changes the covalent structure of the enzymes- eg phosphorylation
what is involved in enzyme association
limits the amount of enzymes that can associate with the enzyme
what is involved in compartmentalisation
limits the accessibility of the enzyme with the substate achieved by the membranes.
which organelle can help with compartmentalisation of enzymes
the mitochondria
what are the regulation points in glycolysis
hexokinase
phosphofructokinase
pyruvate kinase
what are the regulation points in TCA cycle
citrate synthase
isocitrate dehydrogenase
alpha ketoglutarate dehydrogenase
what else can inhibit PFK1
inhibited by ATP- when energy stores are high
what happens when G6P levels are high
allosteric feedback inhibition of hexokinase by G6P
how do we regulate PFK1
by a lot of ATP- this inhibits at the allosteric site and in turn reduces the affinity for fructose 6 phosphate leading to inciting glycolysis
what else is PFK1 sensitive too
ph- acidic conditions reduces its activity so it prevents XS lactic acid buildup
which two enzymes are on the same enzyme
kinase domain and phosphatase domain
how is pyruvate dehydrogenase regulated
by allosteric regulation and covalent regulation
how is the E2 transsacetylase part of pyruvate dehydrogenase limited
by AcetylCOA
how is the E3 dihydrolipopolydehydrogenase part of pyruvate dehydrogenase
NADH
