Final: Lipid metabolism II

Created by BrianEngdahl 

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17 terms

t/f fatty acids with odd numbers of carbons stop the breakdown process when they get to the three carbon propionyl-CoA molecule

T

how do you convert an odd number of carbons fatty acid further? what vitamin is required in this step?

a carboxyl group is added and the molecule is rearranged to succinyl-CoA. Vitamin B12 is required

t/f ketone bodies are not related to the brain

F they are the body's means to provide energy to the brain when glucose levels are VERY low.

t/f starvation and diabetes can cause the need for ketone bodies

T they create low levels of ATP so ketone bodies are needed

explain how ketone bodies are made

by putting together acetyl-CoAs to make four carbon intermediates by revising the reaction catalyzed by thiolase. the four carbon molecules are converted to asia carbon molecule (called HMG-CoA) and it is broken back down to a four carbon molecule and acetyl-CoA.

t/f ketone bodies get to the brain via the blood stream

T

t/f the smell of acetone on someones breath is an indication of a serious problem

T one of the intermediates is chemically unstable and breaks down to acetone

what configuration are unsaturated fatty acids usually produced in, when made biologically?

Cis

what causes trans configurations of fatty acids?

partial hydrogenation of vegetable oils

t/f trans fats are linked to atherosclerosis

T

where are fatty acids synthesized?

the cytoplasm

t/f each step of fatty acid synthesis increases the size of the fatty acid by 4 carbons

F 2 carbons

t/f acetyl groups are shuttled out of the mitochondrion using citrate

T

are most fatty acids even number of carbons or odd

even

explain fatty acid synthesis

fatty acids are bound to a molecule called ACP (acyl carrier protein) instead of CoA.
fatty acid biosynthesis begins with the formation of a three carbon molecule called malony-CoA. this comes about by the addition of a carboxyl group (biotin is a required coenzyme). the enzyme responsible for this reaction is acetyl CoA carboxylase. it is the only regulated enzyme in fatty acid biosynthesis and is activated by citrate and inhibited by palmitate. malonyl-CoA is readily converted to malonyl-ACP

what happens in fatty acid biosynthesis after malonyl-CoA is readily converted to malonyl-ACP

two carbons of the malonyl-ACP are joined to the growing fatty acid and the carboxyl group that was added is lost as carbon dioxide.

fatty acid synthase

the enzyme responsible for fatty acid synthesis and has multiple catalytic activities. it contains all the catalytic activities necessary to make fatty acids up to 16 carbons long. longer fatty acids need other enzymes and are made in the endoplasmic reticulum

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