Lipid Synthesis
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Biochemistry › Lipid Synthesis
The enzyme Acyl-Carrier Protein (ACP) plays an important role in the biosynthesis of which of the following?
Lipids
Carbohydrates
Proteins
Nucleic Acids
Explanation
Acyl-Carrier Protein (ACP) is a protein that is important to the generation of lipids. Specifically, it aids in the production of fatty acids. Furthermore, ACP is just one component of the Fatty Acid Synthase enzyme, which is devoted to the synthesis of fatty acids.
To begin the process, ACP is first activated by having an acetyl-CoA molecule attached to it. Next, a compound called malonyl-CoA is attached to the bound acetyl-CoA. Malonyl-CoA is a three carbon compound, but upon being added to the acetyl-CoA, the malonyl-CoA becomes decarboxylated. The importance of this is that by producing carbon dioxide as a product, this helps to greatly drive the reaction forward.
Keep in mind that there are other chemical transformations happening when these malonyl-CoA molecules are being "stitched" together. Every time a malonyl-CoA is added, the carbon chain becomes increased by two more carbons. This keeps happening until, finally, a fatty acid is generated.
The enzyme Acyl-Carrier Protein (ACP) plays an important role in the biosynthesis of which of the following?
Lipids
Carbohydrates
Proteins
Nucleic Acids
Explanation
Acyl-Carrier Protein (ACP) is a protein that is important to the generation of lipids. Specifically, it aids in the production of fatty acids. Furthermore, ACP is just one component of the Fatty Acid Synthase enzyme, which is devoted to the synthesis of fatty acids.
To begin the process, ACP is first activated by having an acetyl-CoA molecule attached to it. Next, a compound called malonyl-CoA is attached to the bound acetyl-CoA. Malonyl-CoA is a three carbon compound, but upon being added to the acetyl-CoA, the malonyl-CoA becomes decarboxylated. The importance of this is that by producing carbon dioxide as a product, this helps to greatly drive the reaction forward.
Keep in mind that there are other chemical transformations happening when these malonyl-CoA molecules are being "stitched" together. Every time a malonyl-CoA is added, the carbon chain becomes increased by two more carbons. This keeps happening until, finally, a fatty acid is generated.
What is the role of citrate lyase in fatty acid synthesis?
I. It catalyzes the formation of acetyl-CoA and oxaloacetate from citrate and coenzyme A.
II. It converts ATP to ADP and phosphate.
III. It converts ADP to ATP.
IV. It catalyzes the formation of citrate and coenzyme A from acetyl-CoA and oxaloacetate.
I and II
I only
II, III, and IV
I and IV
I, III, and IV
Explanation
Citrate crosses the mitochondrial matrix into the cytosol and is converted into acetyl-CoA and oxaloacetate by citrate lyase during fatty acid synthesis, as part of the citrate shuttle. The process requires hydrolysis of energy-rich ATP bonds.
What is the role of citrate lyase in fatty acid synthesis?
I. It catalyzes the formation of acetyl-CoA and oxaloacetate from citrate and coenzyme A.
II. It converts ATP to ADP and phosphate.
III. It converts ADP to ATP.
IV. It catalyzes the formation of citrate and coenzyme A from acetyl-CoA and oxaloacetate.
I and II
I only
II, III, and IV
I and IV
I, III, and IV
Explanation
Citrate crosses the mitochondrial matrix into the cytosol and is converted into acetyl-CoA and oxaloacetate by citrate lyase during fatty acid synthesis, as part of the citrate shuttle. The process requires hydrolysis of energy-rich ATP bonds.
Which statement about fatty acids is false?
Fatty acid synthesis takes place in the mitochondria
Beta-oxidation takes place in the mitochondria
Fatty acids are aliphatic
Carnitine transports fatty acids into the mitochondrial matrix
None of the other answers is false
Explanation
Beta-oxidation is the process by which fatty acid molecules are broken down in the mitochondria to generate acetyl-CoA, which then enters the Krebs cycle. Fatty acids are not aromatic (they do not have aromatic rings), rather they are organized in straight chains of hydrocarbons and are therefore aliphatic. Carnitine transports long-chain acyl groups from fatty acids into the mitochondria (so that they can undergo beta-oxidation). Fatty acid synthesis, however, takes place in the cytosol.
In what order does fatty acid synthesis occur?
Condensation, reduction, dehydration, reduction
Reduction, condensation, dehydration, reduction
Reduction, reduction, dehydration, condensation
Condensation, reduction, reduction, cleavage
Oxidation, hydration, oxidation, cleavage
Explanation
The proper order for fatty acid synthesis is condensation, reduction, dehydration, and reduction once again. This creates an activated acyl group that has been lengthened by two carbons through this anabolic biosynthetic pathway.
Where are triglycerides produced in the body and what hormone regulates their production?
I. In the adipose tissue and liver. Their production is regulated by insulin and glucagon.
II. In the blood and liver. Their production is regulated by epinephrine and antidiuretic hormone.
III. In the blood as very-low density lipoproteins and chylomicrons. Their production is regulated by epinephrine and growth hormone.
IV. In the muscle. Their production is regulated by growth hormone.
I only
II and III
III and IV
I and II
I and IV
Explanation
Triglycerides are produced in the adipose tissue and liver. Their production is regulated by insulin and glucagon. They are not directly regulated by growth factors or antidiuretic hormone (ADH). Also, they are transported in the blood as lipoproteins, but are not produced in the blood.
In what order does fatty acid synthesis occur?
Condensation, reduction, dehydration, reduction
Reduction, condensation, dehydration, reduction
Reduction, reduction, dehydration, condensation
Condensation, reduction, reduction, cleavage
Oxidation, hydration, oxidation, cleavage
Explanation
The proper order for fatty acid synthesis is condensation, reduction, dehydration, and reduction once again. This creates an activated acyl group that has been lengthened by two carbons through this anabolic biosynthetic pathway.
Which statement about fatty acids is false?
Fatty acid synthesis takes place in the mitochondria
Beta-oxidation takes place in the mitochondria
Fatty acids are aliphatic
Carnitine transports fatty acids into the mitochondrial matrix
None of the other answers is false
Explanation
Beta-oxidation is the process by which fatty acid molecules are broken down in the mitochondria to generate acetyl-CoA, which then enters the Krebs cycle. Fatty acids are not aromatic (they do not have aromatic rings), rather they are organized in straight chains of hydrocarbons and are therefore aliphatic. Carnitine transports long-chain acyl groups from fatty acids into the mitochondria (so that they can undergo beta-oxidation). Fatty acid synthesis, however, takes place in the cytosol.
Where are triglycerides produced in the body and what hormone regulates their production?
I. In the adipose tissue and liver. Their production is regulated by insulin and glucagon.
II. In the blood and liver. Their production is regulated by epinephrine and antidiuretic hormone.
III. In the blood as very-low density lipoproteins and chylomicrons. Their production is regulated by epinephrine and growth hormone.
IV. In the muscle. Their production is regulated by growth hormone.
I only
II and III
III and IV
I and II
I and IV
Explanation
Triglycerides are produced in the adipose tissue and liver. Their production is regulated by insulin and glucagon. They are not directly regulated by growth factors or antidiuretic hormone (ADH). Also, they are transported in the blood as lipoproteins, but are not produced in the blood.