Exam 4

Question 1

Principle Stored Energy Reserve

Answer 1

Triacylglycerols

Question 2

Structure of Fatty Acids

Answer 2

CH3(CH2)COO

• Generally even number of carbon atoms
• Odd and trans Fats are less common
• around 90% are esterified and 10% flow freely attached to Serum Albumin in the blood
• More degrees of unsaturation= more fluid
• longer= less fluid

Question 3

Linoleate

Answer 3

18: 2 delta 9,12

- essential FA

Question 4

linolenate

Answer 4

18: 3 delta 9,12,15

- essential FA

Question 5

Omega carbon

Answer 5

carbon at the end of a FA chain

Question 6

Where FAs are synthesized

Answer 6

In the liver and mammary glands

• only in the cytosol of cells
• requires the transport of Acetyl CoA into the cytosol via the citrate transport

Question 7

FA synthesis require ___ and ____ as energy sources

Answer 7

ATP and NADPH

Question 8

FA are synthesized from ______ derived from _____ and _____

Answer 8

Acetyl CoA derived from excess protein and carbohydrates

Question 9

Citrate is Shuttled in ….

Answer 9

High energy states. ATP will inhibit the isocitrate dehydrogenase enzyme and citrate that accumulated can then be shuttled out to make FAs

Question 10

Overview of Fatty Acid Synthesis

Answer 10

2 acetyl Coa-> Reduction-> dehydration-> reduction-> condensation

Question 11

Acetyl CoA carboxylase

Answer 11

Acetyl Coa-> malonyl CoA in FA synthesis

• requires ATP
• HCO3
• Biotin cofactor

Question 12

ACC Allosteric control

Answer 12

Polymer stabilization via Citrate and destabilization via Fatty Acyl CoA

Question 13

ACC regulation via Phosphorylation

Answer 13

• Regulated via cAMP, epinephrine, and protein kinase cascade
• These and AMP will all deactivate the ACC via a AMPK in the Fasted state
• Dephosphorylation of ACC occurs in the presence of insulin

Question 14

Fatty Acyl Synthase Complex

Answer 14

• Single polypeptide (Dimer) in Humans with 7 activities

- Can be multiple polypeptides in Plants, Yeast, and Bacteria

Question 15

ACP structure

Answer 15

Very similar structure to CoA and shares the phosphopantetheine group but is attached to serine instead of an adenosine

Question 16

FA synthesis Charging step

Answer 16

• Malonyl/ Acetyl CoA ACP Transferase (MAT)
  1. Transfers Acetyl CoA to the ACP domain
  2. Acetyl group then gets transfered to the beta- keto acyl ACP synthase (KS) domain
  3. Malonyl/ Acetyl CoA ACP Transferase then adds an malonyl CoA to the ACP domain

Question 17

FA synthesis Condensation Step

Answer 17

• Decarboxylation of the malonyl CoA allows for the nucleophilic attack for the acetyl group carbonyl group
• Forms Beta-ketobutyryl ACP

Question 18

Suppose 14C-labeled CO2 is used to form malonyl-CoA from acetyl-CoA. If this labeled malonyl CoA is used for palmitate synthesis, which carbon atom(s) in the fatty acid would be radiolabeled?

Answer 18

NONE

Question 19

First Reduction in FA synthesis

Answer 19

• B ketobutyryl ACP reductase
• Uses an NADPH
• Forms B-hydroxybutyryl- ACP

Question 20

FA synthesis Dehydration

Answer 20

• Occurs via the B-hydroxybutyryl ACP dehydratase (DH)
• Removes a water molecule
• Form Trans-delta2- butenoyl-ACP

Question 21

Second reduction in FA synthesis

Answer 21

• Uses the Enoyl-ACP reductase (ER)
• Forms Butyryl-ACP
• Uses NADPH

Question 22

NADPH sources

Answer 22

• PPP pathway
• Malic enzyme in the cytosol
• Converts Malate to pyruvate for import into the mitochondria

Question 23

Elongation and desaturation of palmitate

Answer 23

• Occurs in the smooth ER
• Cannot desaturate past carbon 9
• desaturations occur via Fattyl Acyl CoA desaturates which are mixed function oxidases that generate H2O and require O2

Question 24

Respiratory Distress Syndrome

Answer 24

• Failure to synthesize enough dipalmitoyl phosphatidylcholine
• DPPC is generally used to reduce the surface tension in the fluid surrounding the alveoli