BIOCHEM2 week 8 pt2

winniesmith1's version from 2017-04-03 13:24

Section 1

Question Answer
What does NEFA stand forNon-esterified fatty acids
What are NEFA used forthe primary energy fuel for most tissues under fasting conditions
When are NEFA producedin adipose tissue by the hydrolysis of triglycerides
What is hydrolysis of NEFA catalysedintracellular hormone sensitive lipase (HSL). Then released into plasma
What is HSL acitivity stimulated byGlucose, Adrenaline, Noradrenaline, ACTH, insulin
What is rate of utilisation for NEFA directly proportional toCirculating plasma levels
How are NEFA transportedBound to plasma proteins (albumin) as not water soluble.
What are the target tissues for NEFAmuscle and liver- enter via diffusion
Do NEFA compete with other moleculesYes. Compete for albumin binding sites with other molecules (eg tryptophan)
How much NEFA can be carriedApprox 2mmol. If goes above then unbound FA (triaclyglycerol) also rises.
What happens NEFA concentrations during the daythey fluctuate. Tend to mirror those of plasma glucose and insulin.
What happens to NEFA if glucose increassedecreases. because insulin inhibits HSL.
Does exercise and illness influence NEFA conc.Yes. Increase. Release of Adr, NAdr/ACTH

Section 2

Question Answer
Are triacylglycerol (a.k.a triglyceride/TG) water soluble?No. Circulate in plasma as lipoproteins
How is dietary fat transportedas chylomicrons to adipose tissue and skeletal muscle
How is endogenous fat transportedby other lipoproteins e.g. VLDL transports TG synthesized in the liver
Why do individual TG levels vary widelydue to body build/shape, genetics and fitness (not health)
What is the total TG levels in plasma after overnight fastapprox 1mmol
What is TG level post mealIncreases. Change variable according to meal contents.
What is chylomicron concentration after fastingapprox zero. 0.4-0.6mmol after meal (depending on meal content). Prolonged increase due to delayed gastric emptying.

Section 3

Question Answer
What are the products of HSLGlycerol and NEFA
What happens to the glycerolGluconeogenic substrate (liver)
Which tissue expresses the Glucose transporter with the highest affinity for glucoseBrain (Glut-3)
What is the specific function of chylomicronsTransportation of dietary fat to skeletal muscle and adipose tissue.
What is the chylomicron concentration after a prolonged period of fasting0.
Which hormone has the most profound effects on HSLInsulin (inhibitor)

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