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Biochem wk9- control of metabolism 2

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winniesmith1's version from 2017-06-08 23:28

Section 1

Question Answer
plasma levels when you wake upPlasma glucose level-low. Plasma insulin level- low. Plasma NEFA level is- high.
what is NEFAnon-esterified fatty acids
waking up- glucose enters the blood from which two sourcesbreakdown of liver glycogen and hepatic gluconeogenesis
what is the waking up glucose used bythe brain and red blood cells etc/building cells
how does the carbon get recycled following oxidisation in the brainlactate back to liver for gluconeogenesis
why do skeletal muscles not use much glucoselow levels of plasma glucose and insulin. NEFA levels high- signal to muscle about which energy system to use
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Section 2

Question Answer
What is the net breakdown of protein in muscle due tothe lack of insulin
net breakdown of protein- Some AA released (branched chain AA) oxidised in muscle, transfer there amino group to what AND where does this come frompyruvate- from Muscle Glycogen breakdown and small amount of glucose uptake and activity in the muscle.
what is pyruvate used to formalanine
what is the fate of alaninetaken up by the liver as a substrate for gluconeogenesis
waking up- what mechanism stimulates the liberation of fatty acids from adipose tissuerestraint of hormone-sensitive lipase (not occurring when wake up therefore high levels)- why? lack of insulin
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Section 3

Question Answer
NEFA are the preferred fuel for the muscle - why?In the Liver fatty acids are taken up and oxidised rather than esterified. due to low insulin/glucagon ratio
If FA are oxidsied in the Liver, what is the ATP generated used for ?Driving Gluconeogenesis + other metabolic functions of the liver.
FA oxidation is accompanied by the formation of what ?ketone bodies (kb)
The conc of KB is not sufficient to make them a major source of fuel but they are taken up and used by which tissues ?Muscle – Brain – Adipose
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Section 4

Question Answer
Lazy day (plenty of food and little exercise) breakfast (CHO-Fat- Protein). Time course for glucose and AA's to enter the circulation?15-30mins
After such a large and lazy breakfast how long will plasma glucose levels remain elevated ?3-4 hours
What happens as plasma glucose (HPV) increaseso does glucose uptake in the liver, thus acting as a buffer for blood glucose in the systemic circulation
Although the blood is buffered, we still see a rise in blood glucose and thus a change in endocrine activity. why?pancreas response increases insulin secretion.
What happens to glucagon levels after lazy breakfast/rise in blood glucoseslightly increased but ration goes down
Under these influences (breakfast time option 1)- what happens to the liver metabolismSwitch in glycogen metabolism from lysis to synthesis. Thus ingested and absorbed CHO remains with the liver.
(breakfast time option 1) the liver also takes up many AA from the portal vein but what does the liver leave for the systemic circulation?branched chain amino acids
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Section 5

Question Answer
(breakfast time option 1) What impact does the increase in glucose and insulin concentrations have on adipose tissue and whyThere is a reduction in release of NEFA. Because: uptake of NEFA in tissue driven by plasma levels so it falls to allow glucose uptake and utilisation
With the change in plasma glucose and NEFA occurring, how long after the big breakfast meal would you expect NEFA to reach their lowest level? and why does this happen?1-2hours. This decrease in plasma NEFA removes the drive for muscle to oxidise FA and metabolism in the muscle switches toward glucose uptake and utilisation.
if glucose oxidation is increased what does the muscle produce more ofLactate and pyruvate
With the change in muscle metabolism there is also an increase in uptake of AA from the circulation but what type of AA are taken up and what are they used forBranched chain AA. Oxidised for fuel (note: at this stage there is a net stimulation of protein synthesis).
Describe the metabolic picture within the 1st 4hrs after a mealreflects an intense switch to glucose utilisation and particularly to glucose storage as glycogen. The bodies fat stores are conserved by suppression of FA release from adipose tissue and the body is in a state of storage and conservation
Storage mode is reinforced by the arrival of whatchylormicrons
Chylormicrons carry what? to where? and why?Fats, to liver and adipose tissue, for storage.
At the same time as chylormicrons are released, insulin stimulated which enzyme? which does what?lipoprotein lipase- stimulates esterification and storage of fat
How long does it take for fat storage and glucose useup too about 4 hours.
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Section 6

Question Answer
LUNCH- what happens at lunch time same as before but this time from a primed state rather than a 'starvation' state
What does eating lunch mean?recovery of fuel stores? or deposition of fat?
Breakfast option 2- healthy person eats healthy CHO breakfast- what metabolic response do we have?Similar but with sharper shorter glucose peak
option 2. Healthy breakfast, 60 mins later out for exercise. What is the endocrine response?Adrenaline switch on FA metabolism
option 2- what happens to fat metabolism?Oxidation of FA as fuel source
option 2- what happens to blood glucose concentration?Not as high (or faster return to baseline)
option 2- what happens to insulin levels?Reduced insulin response
option 2- what happens to glucagon suppressionsuppression reduced
After healthy morning activity, lunch will be a low fat but protein and CHO rich meal. What is the net result at the end of the day of this continued activityless substrate stored and more oxidised.
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