Fatty Acid Synthesis

Question 1

What is fatty acid biosynthesis

Answer 1

the conversion of acetyl-CoA into fatty acids in the cytoplasm using ATP and NADPH to provide the required energy

Question 2

Where does fatty acid synthesis occur

Answer 2

cytoplasm

Question 3

What is the catalyst for FA synthesis

Answer 3

Acyl Carrier Protein (ACP)

Question 4

What is a Acyl Carrier Protein (ACP)

Answer 4

The acyl carrier protein has a side chain that carries the growing fatty acid and it rotates clockwise letting the side chain sweep over the multienzyme system in a ‘merry go round” mechanism.
The “swinging arm” side chain is a phosphopantatheine prosthetic group

Question 5

How many steps are there in FA synthesis

Answer 5

6

Question 6

What is step 1 of FA synthesis

Answer 6

Priming of the system of Acetyl-CoA

Question 7

What is step 2 (a) of FA synthesis

Answer 7

Malonyl-CoA is synthesized

Question 8

What is step 2 (b) of FA synthesis

Answer 8

Loading of the malonyl-ACP complex

Question 9

What is step 3 of FA synthesis

Answer 9

condensation reaction; 2 fragments are joined together. An unfavorable reaction driven by the energy of the acetyl-synthase C-S bond which is broken

Question 10

What is step 4 of FA synthesis

Answer 10

the first reduction reaction; the ketone group is reduced to an alcohol. Driven energetically by the NADPH oxidation

Question 11

What is step 5 of FA synthesis

Answer 11

dehydration reaction (water is removed)

Question 12

What is step 6 of FA synthesis

Answer 12

the second reduction driven by NADPH oxidation

Question 13

What happens after step 6 in FA synthesis

Answer 13

The cycle then repeats but used butyry;-ACP as the starting substrate. In mammals the cycle keeps going around adding C2 each time until C16 palmitic acid is reached

Question 14

Which steps are reduction reactions in FA synthesis

Answer 14

Step 4 and Step 6

Question 15

What are the differences between FA synthesis and b-oxidation

Answer 15

• FA synthesis involves reductions reactions where b-oxidaiton involves oxidation reactions
• FA synthesis occurs in the cytoplasm while b-oxidaiton occurs in the mitochondrial matrix
• FA synthesis has 6 steps while b-oxidation has 5 steps
• FA synthesis produces palmitate while B-oxidation produces acetyl-CoA
• FA synthesis adds 2 carbon atoms at a time while b-oxidation cleaves 2 carbon atoms at a time