Biochem Lec 3 - Lipid Metabolism / Flashcards
(23 cards)
enzymes that are responsible for desaturating long fatty acids are located where and how do they work
in the SER
add cis double bonds
where is the first double bond typically inserted
between carbons 9&10, producing primarily 18:1(9) and small amounts of 16:1(9)
where can mammals not introduce a c=c bond
from carbon 10 to the omega end of the chain
structure of triacylglycerols
carbon 1 saturated
carbon 2 unsaturated
carbon 3 either
TAGS can or cannot form stable micelles by themeselves
they cannot
TAGs coalesce within what to form oily droplets that are nearly anhydrous (dont liek water)
adipocytes
what is the initial acceptor of FAs during TAG synthesis
glycerol phosphate
what is the FA activated from
it must be in the activated form to paricipate in metabolic processes
attached to CoA
what does fatty acyl CoA synthases (thiokinases do)
convert FA to its activated form (attached to CoA)
fate of TAG
in adipose tissue, TAG is stored in a nearly anhydrous form as fat droplets in cytosol of cells
little TAG is stored in liver
most are exported, packaged with other lipids and apolipoprotein particles called VLDL
energy from fats
9 kcal/gram
energy amount from carbs and proteins respectively
4 kcal/gram
mobilization of stored fat requires the hydrolytic release of fatty acids and glycerol from their TAG form is initiated by what
hormone-sensitive lipase
what does hormone-sensitive lipase do
remove fatty acid from carbon 1 or carbon 3 of TAG
beta oxidation
breaks down fatty acids, successively removing 2 carbon fragments from the carboxyl end of fatty acyl CoA, producing acetyl CoA, NADH, FADH2
where does beta-oxidation of fatty acids occur
mitochondria
what does the carnitine shuttle do
transports long chain fatty acids into the mitochondria from cytosol
final 3 carbon molecule (propionyl CoA) is metabolized into what
succinyl CoA
why do unsaturated fatty acids provide less energy
bc they are less highly reduced than saturated fatty acids
when will ketone body production occur
when the result of excess acetyl-CoA from B-oxidation
-high lipid intake and low carb intake
-starvation (body consumes fats)
-diabetes (problems with carbohydrate catabolism)
what part converts acetyl CoA to ketone bodies
liver mitochondria
when formation of ketone bodies is greater than rate of use, their levels raise in blood and urine
where is this often seen
in uncontrolled type 1 diabetes
frequent symptom of diabetic ketoacidosis is what
fruity odor of breath (acetone)
