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BIOC3560 Final Exam with questions and correct answers ||latest update 2024/2025 || grade A
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BIOC3560 Final Exam with questions and correct answers||latest update 2024/2025 || grade A
what length of FA require the carnitine shuttle?
>14C
list the steps in the carnitine shuttle
- cytoplasmic FA is converted to fatty acyl CoA using acyl CoA synthetase
- fatty acyl CoA is transferred to the carnitine molecule by carnitine acyl
transferase I
- fatty acyl carnitine enters the mitochondria using facilitated diffusion through the
carnitine transporter
- fatty acyl COA is regenerated in the mitochondria by carnitine acyl transferase II
what does malonyl CoA inhibit in the carnitine shuttle?
carnitine acyl transferase I
What does acyl CoA synthetase do?
cytoplasmic FA to fatty acyl CoA
what does carnitine acyl transferase I do?
transfers fatty acyl CoA on to a carnitine molecule in cytosol
what does the carnitine transporter do?
facilitated diffusion of fatty acyl carnitine into the mitochondria
what does carnitine acyl transferase II do?
regenerates fatty acyl CoA in the mitochondria by removing carnitine
What are the 3 steps in complete oxidation?
1) Beta oxidation
2) Acetyl COA enters TCA to be oxidized
3) NADH and FADH2 donate their electrons to the ETC
Explain the process of beta oxidation
,dehydrogenation: fatty acyl CoA is converted to trans-delta2- enoyl-CoA by acyl
COA dehydrogenase and FAD captures an electrons and is converted to FADH
hydration: trans-delta2-enoyl-CoA is converted to L-B-hydroxyacyl-CoA by enoyl-
CoA hydratase and H2O is added to the reaction
dehydrogenation: L-B-hydroxyacyl CoA is converted to B-ketoacyl-CoA by B-
hydroxyacyl COA dehydrogenase and NAD+ captures electrons and is converted
to NADH + H+
cleavage: B-ketoacyl CoA is converted to acetyl COA + fatty acyl CoA-2 by acyl
COA acetyl transferase and CoASH is added to the reaction
- then Beta oxidation repeats until just acetyl CoA is left
What does acyl COA dehydrogenase do?
- fatty acyl COA to trans-delta2-enoyl CoA
- helps with two double bond problem by converting cis,delta4 to trans-delta2 cis-
delta4
What does enoyl-CoA hydratase do?
trans-delta2-enoyl-CoA to L-B_hydroxyacyl CoA
What does B-hydroxyacyl-COA dehydrogenase do?
L-B-hydroxyacyl COA to B-ketoacyl-CoA
What does acyl CoA acetyl transferase do?
- B-ketoacyl CoA to acetyl COA + fatty acyl CoA-2
- in ketone body synthesis, combines 2 acetyl CoA molecules to make acetoacetyl
CoA
- Acetoacetyl CoA to 2 acetyl COA molecules in ketone body catabolism
Which end is acetyl COA removed from during beta oxidation?
carboxyl end
What are the 3 problems that could occur during beta oxidation?
odd number of carbons, cis double bonds, and two double bonds
What is the solution to the odd number of carbons in beta oxidation?
- B oxidation continues until you have propionyl COA (3C molecule)
- can't be oxidized in step 1 of B oxidation (acyl COA dehydrogenase)
,- propionyl CoA enters separate pathway to be carboxylated and become succinyl
CoA (4C)
- succinyl COA enters TCA
What is the solution to the cis-double problem of beta oxidation?
- beta oxidation only works on trans double bonds
- beta oxidation will run normally until cleavage reaches the cis double bond (step
1 acyl CoA dehydrogenase can't oxidize this)
- Cis C3-C4 is converted to trans C2-C3 via delta3-delta2-enoyl COA isomerase
- Now substrate for step 2 of beta oxidation (bypass step 1)
- Net loss of 1 FADH2
What does delta3-delta2-enoyl CoA isomerase do?
- fixes cis double bond problem turning cis C3-C4b into trans C2-C3
- helps with the two double bond problem by converting trans detla3 into trans
delta2
- helps with two double bond problem by turning cis-delta3-delta6 into trans
delta2-cis-delta6
What is the solution to the two double bond problem in beta oxidation?
double bonds are a position 9 and 12
- B oxidation proceeds normally for 3 rounds until you are left with FA cis-delta3-
delta6
- cis delta3, delta6 is converted to trans detla2, cis delta6 by delta3-delta2 enoyl-
CoA isomerase
- substrate for step 2 of beta oxidation (enoyl CoA hydratase)
- beta oxidation continues as normal but are left with cis-delta4
- cis-delta4 is converted to trans,delta2 cis, delta4 via acyl CoA dehydrogenase (not
a substrate for step 2 of beta oxidation enoyl COA hydratase)
- trans,delta2 cis, delta4 is converted to trans-delta3 via 2,4-dienoyl-CoA reductase
and NADPH donates electrons to become NAD+
trans delta3 becomes trans detla2 via delta3,delta2 enoyl CoA isomerase
What does 2,4-dienoyl-CoA reductase do?
converts trans-delta2 cis-delta4 to trans-delta3
How do you name the carbon atoms of FA?
, greek letters: start counting after the carboxyl carbon
numbering: start counting at the carboxyl carbon
What is the greek naming system used for for FAs?
sites of chemical reactivity
What is the numbering naming system used for for FAs?
locations of features (ex. double bonds)
What is a saturated vs an unsaturated FA and implication?
staurated: no double bonds, single bonds are rotatable
unsaturated: double bonds, atoms around double bond are bent and cannot rotate
Relative types of energy of different molecules
circulating fuels (least)
glycogen
amino acids
triacylglycerols (most)
What is the second most readily source of energy?
glycogen - would breakdown before AAs because they are needed to perform
functions in the body
What form are FAs stored in?
triacylglycerols
Explain the process of FA mobilization
- hormone binds Rc
- Rc send a signal which activates a kinase
- PKA phosphorylates a lipase (HSL)
- PKA phosphorylates from perilipin (perilipin coats TAGs in adipocytes to form
lipid globules)
- phosphorylates perilipin released the protein CGI
- CGI activates adipocyte triacyl glycerol lipase (ATGL) which released the first
FA by cleaving off the glycerol head
- HSL releases the second FA from diacylglycerol
- monoacyl glycerol lipase (MGL) cleaves the third FA from monoacyl glycerol
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