Lecture 12: Triglyceride and Fatty Acid Synthesis

Question 1

Fatty Acid Synthesis

• Occurs in the ______\_
• Energy storage in times of excess, abundant ______\_ and ATP
• _____\_ and Mammary glands are major sites of FA synthesis

Answer 1

Fatty Acid Synthesis

• Occurs in the Cytosol
• Energy storage in times of excess, abundant acetyl co-A and ATP
• Liver and Mammary glands are major sites of FA synthesis

Question 2

Fatty Acid Synthesis Pathway:

• Acetyl CoA (# Carbons?) is converted to malonyl CoA (# Carbons?) which donates activated 2C acetyl units
• Elongation of FA chains is repeated until the FA chain reaches ____\_ carbons in length ( palmitic acid)

Answer 2

Fatty Acid Synthesis Pathway:

• Acetyl CoA (2C) is converted to malonyl CoA (3C) which donates activated 2c acetyl units
• Elongation of FA chains is repeated until the FA chain reaches 16 carbons in length(palmitic acid)

Question 3

_____________:

• Method of getting Acetyl CoA from mitochondrial matric to cytoplasm for Fatty Acid Synthesis.
• Also generates NADPH for FA synthesis.
• Converted to _____\_ which then returns to mitochondria for cycle to repeat

Answer 3

Citrate Shuttle:

• Method of getting Acetyl CoA from mitochondrial matric to cytoplasm for Fatty Acid Synthesis.
• Also generates NADPH for FA synthesis.
• Converted to Pyruvate which then returns to mitochondria for cycle to repeat

Question 4

_______________:

• The formation of Malonyl CoA from Acetyl CoA is facilitated by this enzymes
• ____\_ acts as a cofactor.

Answer 4

Acytel COA Carboxylase (ACC):

• The formation of Malonyl CoA from Acetyl CoA is facilitated by this enzyme.
• Biotin acts as a cofactor.

Question 5

Acytel CoA Carboxylase catalyzes an irreversible step in FA Synthesis and ______\_.

• __________ inhibits beta-oxidation by blocking FAentry into mitochondria (carnitine acyltransferase)

Is a rate-limiting step subject to regulation _____\_and by phosphorylation. ACC is _____\_ as a monomer.

Answer 5

Acytel CoA catalyzes an irreversible step in FA Synthesis and oxidation.

• malonyl-CoA inhibits beta-oxidation by blocking FA entry into mitochondria (carnitine acyltransferase)

Is a rate-limiting step subject to regulation Allosterically and by phosphorylation. It is Inactive as a monomer.

Question 6

______________: Carrier of Intermediates in Fatty Acid Synthesis. Attaches via the SH group

Answer 6

Acyl Carrier Protein: Carrier of Intermediates in Fatty Acid Synthesis. Attaches via the SH group

Question 7

______________\_: Has 5 distinct enzyme activities, acts as FA production line.

Binds to the Acyl Carrier protein which is carrying reaction intermediates

Answer 7

Fatty Acid Synthase: Has 5 distinct enzyme activities, acts as FA production line.

Binds to the Acyl Carrier protein which is carrying reaction intermediates

Question 8

Cycle of 4 reactions that Extends Fatty Acid chain

Answer 8

• Condensation
• Reduction
• Dehydration
• Reduction

Question 9

Reactions to elongate fatty acid chain is the reverse of the 4 reactions of _______\_ Pathway

Answer 9

Reactions to elongate fatty acid chain is the reverse of the 4 reactions of Beta Oxidation Pathway

Question 10

____________: product of FA synthase that inhibits ACC via negative feedback

Answer 10

Palmitoyl CoA: product of FA synthase that inhibits ACC via negative feedback

Question 11

_______\_: signals energy abundance and activates ACC to increase FA synthesis

Answer 11

Citrate: signals energy abundance and activates ACC to increase FA synthesis

Question 12

Phosphorylation of ACC by kinases ______\_it and dephosphorylation by phosphatases _____\_ it

Answer 12

Phosphorylation of ACC by kinases inactivates it and dephosphorylation by phosphatases activates it

Question 13

Hormones regulate ACC activity by controlling the activity of protein kinases and phosphatases:

• ______\_ signals energy is low, activates protein kinase which initiates Beta Oxidation.
• ______\_ signals energy is abundant, activates protein phosphatase which facilitates FA Synthesis

Answer 13

Hormones regulate ACC activity by controlling the activity of protein kinases and phosphatases:

• Glucagon signals energy is low, activates protein kinase which initiates Beta Oxidation.
• Insulin signals energy is abundant, activates protein phosphatase which facilitates FA Synthesis

Question 14

ACC Inhibitor leads to:

• _______\_ Fatty acid synthesis
• _______\_ Fatty acid oxidation
• _______\_ Insulin Sensitivity
• _______\_ Body fat and weight

Answer 14

ACC Inhibitor leads to:

• Decreased Fatty acid synthesis
• Increased Fatty acid oxidation
• Increased Insulin Sensitivity
• Decreased Body fat and weight

Question 15

Main sites of Triglyceride Synthesis:

__________: for reconstitution of dietary TG’s broken down to be absorbed

_________ : for storage

__________: primary site of synthesis for distribution to other tissues

Answer 15

Main sites of Triglyceride Synthesis:

Intestines: for reconstitution of dietary TG’s broken down to be absorbed

Adipose Tissues for storage

Liver primary site of synthesis for distribution to other tissues

Question 16

Inhibitors of fatty acid synthesis are potential therapeutic agents for treating ____\_and ____\_

Answer 16

inhibitors of fatty acid synthesis are potential therapeutic agents for treating obesity and cancer