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27 Cards in this Set
- Front
- Back
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what is the first step in getting energy from fatty acids
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FREE the fatty acid from lipids.
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what is major type of lipid fatty acids stored in
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Triacylglycerols in adipose tissue
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What are the three phases of lipid catabolism?
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1: fatty acid mobilization (STAGE 1)
2. fatty acid activation (STAGE 1) 3. fatty acid oxidation (STAGE 2/3) |
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What are the three STAGES of lipid catabolism
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Stage 1. Mobilization/activation of fatty acids
Stage 2: F.A. Oxidation to Acetyl CoA Stage 3: Acetyl CoA oxidation via CAC |
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how many acetyl CoA's are produced per TAG?
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number of carbons/2
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How are F.A./TAG's freed from adipose cells?
what enzyme? |
Break down TAG into glycerol and fatty acids, one at a time.
lipoase |
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how is lipase activated?
what does it do? |
by hormonal regulation (glucagon, epinephrine, norepin, ACTH
hydrolyzes TAG's into glycerol + fatty acids. |
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how is lipase inhibited?
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by insulin; insulin says STORE what you just ate as energy. so you don't want to break down TAG's.
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Step 2 in fatty acid catabolism:
activation? how many steps? |
-transfer fatty acid to CoA. two steps:
1. Hydrolysis of ATP to form phosphoester bond (fatty acid bound to AMP) and PPi. (acyl adenylate) 2. Break phosphoester bond and form thioester bond - gives acyl CoA + AMP |
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where does fatty acid activation take place?
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in cytoplasm
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what enzyme catalyzes F.A. activation (both steps)?
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Acyl CoA synthetase
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what are the two products of fatty acid degradation?
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Activated acyl group
activated acetyl group |
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what are the f.a. metabolism enzymes
oxidation hydration oxidation cleavage(thiolysis) |
1. acyl coA dehydrogenase
2. enoyl coA hydratase 3. hydroxyacyl coA dehydrogenase 4. beta-ketothiolase |
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what is ATP yield per molecule of palmitate
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106
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what is yield per palmitate?
-coA -NADH -FADH2 how many ATP used |
8
7 7 2 for activation |
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what gives more ATP per gram, and how much more than the other: fat or glucose
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FAT: gives 2.5 times as much ATP per gram of fat than gram of glucose.
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What is the first step of F.A. syntheis?
enzyme? |
Activation of Acetyl Co-A - commitment to f.a. synthesis.
CARBOXYLATION - gives malonyl CoA. enzyme: acetyl coA Carboxylase |
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what significant thing is required to start f.a. synthesis?
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ATP cleavage to ADP + Pi.
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what is significant about acetyl CoA carboxylase?
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-It is allosteric; affected by hormones.
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Significant differences between f.a. synthesis/degradation:
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-ACP versus CoA
-Reductions use NADPH (synth) vs. NAD+ for oxidation (degrad) |
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Difference between bacterial/mammalian fatty acid synthesis:
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Enzyme - complex vs. free enzymes.
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what is the similarity between ACP and Coenzyme A?
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both have a phosphathiene arm, but CoA has an ADP where ACP has a protein so it's a macro CoA
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what transfers acetyl and malonyl from CoA to ACP?
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transacylases.
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General Fatty Acid Synthase characteristics to know:
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-Homodimer
-7 active sites -one single polypeptide chain |
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Domain 1:
AT MT CE |
Acyl transferase
Malonyl Transferase Condensing Enzyme All on D1 of fatty acid synthase |
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All on Domain 2
KR DH ER ACP |
keto reductase
dehydrogenase enoyl reductase acyl carrier protein all on domain 2 of f.a. synthase |
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How does fatty acid synthase work?
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Malonyl CoA transfers from MT to ACP
Acetyl CoA transfers from AT to CE. The two condense; then reduction at 3 other sites. Then transfer elongated f.a. to CE, ready for antother round. |
