Carbohydrate Metabolism Flashcards
What is ATP
a high energy nucleotide with 3 phosphate attached to a ribose sugar
what happens when ATP is hydrolised
chemical energy is released losing a phosphate group
is endergonic or exergonic energetically favoured
exergonic
how much ATP is turned over with energy expenditure of 2000Kcal
~45Kg
what is phosphagen pathway used for
explosive, anaerobic, lots of energy quickly
what is mitochondrial respiration pathway used for
slow endurance, aerobic, less ATP slowly
how long would stored ATp last in maximal exercise
~3 seconds
what is myokinase maximal rate of ATP resynthesis
0.9mmol/kg/sec
what is CK maximal rate of ATP resynthesis
2.6mmol/kg/sec
is myokinase reaction aerobic or anaerobic
anaerobic
why is the myokinase reaction favoured
reduced ATP, increase ADP, AMP
PCr outweighs Cr in muscle favouring what
conversion to Cr and ATP
how long do PCr stores last during maximal exercise
~7 seconds
how much larger are PCr stores than ATP
3-4x larger
why does ATP levels not drop a signifcant amount after exercise
doesnt drop below 60% due to enzymes (myokinase and creatine kinase)
why does Pcr have a significant level drop after exercise
it provides the initial explosive demand ~7sec
what change is associated with breakdown of glucose
negative change in Gibbs free energy
why does Glucose have such a huge drop in gibbs free energy
due to multiple complex bonds in hexose sugar
where and how are oligosaccharides broken down into disaccharides
in the villi of small intestine
lactase, maltose and sucrose then break disaccharides into what
monosaccharides
where is glycogen mainly stored
liver (3-7%) and muscle (1-1.5%)
where is glycogen usually located
optimally between thick and thin filaments near mitochondria
what is the process of glycogen synthesis
uridine triphosphate react with glucose to provide energy to build glycogen chain
what enzymes are involved in glycogen synthesis
glycogenin, glycogen synthase, branching enzyme
what type of reaction is glycogen synthesis
anabolic condensation
what is the process of glycogen breakdown
a phosphate group is added to glucose to release it from glycogen chain
what enzymes are involved in glycogen breakdown
glycogen phosphorylase, debranching enzyme
what type of reaction is glycogen breakdown
catabolic hydrolysis
glycogen phosphorylase activity activity in muscle is increased by
increased Pi, Ca2+, adrenaline, AMP/ATP ratio
what are the two phases whihc glycogen resynthesis occurs in
insulin dependent and independent
what is insulin independent phase active and what is it driven by
(0-4hr), low glycogen content, post exercise blood flow, glycogen synthase levels
what is insulin dependent phase active and what is it driven by
(4-24hr), lower rate of synthesis, insulin exclusively drives uptake, carb feeding maximising glucose and insulin levels
what is a hydride ion
a hydrogen ion with an extra electron
what is glycolysis
an anaerobic pathway with a low energy yield taking place in cytosol
what are the reactants of glycolysis
glucose
what are the products of glycolysis
ATP,NADH, Pyruvate
how does exercise affect glycolysis
can augment the glycoltyic rate by 100 fold
what is the krebs cycle
an aerobic metabolic pathway with low energy yield taking place in mitochondiral matrix
reactant of kreb cycle
Acetyl CoA
products of kreb cycle
ATP, NADH, FADH2
kreb cycle in more depth
a series of 9 reactions that oxidise acetly CoA into CO2 via a series of metabolites that produce electron carriers in mitochondria
what is oxidative phosphorylation
an aerobic metabolic pathway with high energy yield taking place in the mitochondrial space and matrix
what are reactants of oxidative phosphorylation
8NADH and 4FADH2 (products of kreb + glycolysis)
what are products of oxidative phosphorylation
26 ATP, 6CO2, 6H20
what else does the ETC do
re-oxidises reduced co-enzymes NADH and FADH2 back to their oxidised forms
how much hydrogen are ejected
10 are ejected but 4 before the electron chain begins
when does enzyme bind ADP and Pi
when 4 protons present, yielding 1 ATP
1 NADH and 1 FADH = how many ATP and protons
1 NADH = 10 protons = 2.5 ATP
1 FADH = 6 proton = 1.5 ATP
