Post absorptive processing of carbs Flashcards
what are the 3 sugars we get from crabs and where to they come from
glucose from starch and glycogen
fructose from sucrose
galactose from lactose
same 2 diseases associated with fructose and galactose
hereditary fructose intolerance
galactosaemia (more rare)
which sugar is most important in infants
galactose which forms 50% of carbs - comes from milk etc
what are four possible uses for glucose
metab to produce energy
conversion for glycogen in store
synthesis of the cellular components (DNA)
conversion to fat for storage
what level must blood glucose be stable at
5mM
below 3 = confusion and coma
above 8 = long term vascular damage
what are the two phases of glycolysis
preparative phase
generating phase
what happens in the preparative phase of glycolysis
glucose to fructose 1-6 biphopshate which requires ATP
what happens during the generating phase of glycolysis
fructose 1-6 diphosphate to 2 pyruvate molecules which generates atp and NADH for more atp production later
what is the difference in yield of atp in aerobic vs anaerobic conditions
2 in glycolysis in anaerobic
5-7 in glycolysis in aerobic
complete oxidation of glucose via kerb - 30-32
what are the three control points of glycolysis
hexokinase/glucokinase
phosphofructokinase
pyruvate kinase
describe the complete reactions of anaerobic glycolysis
pyruvate converted to lactate creating NAD+
NADH converted back turning glyceraldehyde phosphate to 1-3biphosphate glycerine
what is the warburg effect and what is it used for
tumours take up more glucose than other tissues and using PET scan it can be used to identify tumours
what are the two types of glycogen
a1-4 linkages
a1-6 branch points
what is the difference between blood glucose and liver glycogen / muscle glycogen
liver glycogen fluctuates throughout the day which is why people feel ill when they don’t eat
glycogen in muscle doesn’t fluctuate like liver due to different roles
blood glucose is always stable level
describe the steps involved in
conversion of glucose 6 phosphate to glucose 1 phosphate synthesis of UDP - glucose needs a primer chain elongation insertion of branch points
in the liver and kidney what is converted to glucose
glucose 6 phosphate
what are fatty acids used for
converted to triacylglycerols for storage
used to synthesis other lipids for membranes etc
where does fatty acid synthesis occur
mainly in the liver
adipose tissue
breast tissue during lactation
in the cell cytosol
how do you get fat on a low fat diet
fatty acids are synthesis from the cytosolic acetyl CoA, which is produced from citrate
describe the process of triacylclycerol synthesis
addition of fatty acids to a molecule of glycerol 3 phosphate
occurs in endoplasmic reticulum
how is triacylglyerceol stored
in adipose tissue - stored in cytosol
in the liver packaged into VLDL secreted into the blood where it is transport to adipose tissue and other peripheral tissues for energy
from milliseconds to hours how long do these processes take
available substrate
amount of product
activity of enzyme - allosteric modification vs covalent modification
rate of synthesis of enzymes
degradation
milli milli milli secs-mins hours hours
what does amp activated protein kinase do
phosphorylates key enzymes involved in every metabolism in heart adipose tissue liver and muscle
increase energy providing pathways
inhibit anabolic pathways
how does insulin affects glycolysis
increases expression of genes which code from enzymes of glycolysis
decrease those which code for glucoeogenesis
high insulin stimulates glycolysis
