Lipids II

The synthesis of both glycerophospholipids and triacylglycerols involves: A. phosphatidate phosphatase B. CDP-diacylglycerol C. CDP-choline D. phosphoethanolamine E. phosphatidic acid

E. phosphatidic acid

Fatty acid synthesis requires NADPH. What are the main sources of NADPH for FA synthesis? A. malic enzyme (oxaloacetate recycling) B. citric acid cycle C. pentose phosphate pathway D. pyruvate dehydrogenase

A, C. malic enzyme (oxaloacetate recycling), pentose phosphate pathway

Which of the following mechanisms are used for the synthesis of phospholipids? A. Diacylglycerol is activated by CTP and the activated diacylglycerol reacts with the head group to form the phospholipid. B. Diacylglycerol reacts directly with the phosphate head group to form the phospholipid. C. Both diacylglycerol and the head group are activated by CTP and the activated diacylglycerol reacts with the activated head group to form the phospholipid. D. Head group is activated by CTP and the activated head group reacts with the diacylglycerol to form the phospholipid.

A, D. Diacylglycerol is activated by CTP and the activated diacylglycerol reacts with the head group to form the phospholipid, Head group is activated by CTP and the activated head group reacts with the diacylglycerol to form the phospholipid.

Which of the following regulators of acetyl-CoA carboxylase (ACC) activity ACTIVATE ACC (i.e., increase its activity)? A. citrate B. malonyl-CoA C. palmitate D. insulin E. AMP-PK

A, D. citrate, insulin

The carrier of an acyl chain through the synthetic FAS protein complex is: A. ACP B. acetyl coenzyme A C. biotin-activated complex D. serum albumin

A. ACP

What would be the consequences for fat metabolism of a mutation in acetyl-CoA carboxylase (ACC) that replaced the Ser residue normally phosphorylated by AMPK to an Asp residue? A. FA synthesis would be inhibited and FA oxidation would be stimulated. B. FA synthesis would be stimulated and FA oxidation would be stimulated. C. FA synthesis would be stimulated and FA oxidation would be inhibited. D. FA synthesis would be inhibited and FA oxidation would be inhibited.

A. FA synthesis would be inhibited and FA oxidation would be stimulated.

How is acetyl-CoA transported out of the mitochondria? A. It is transported out as citrate via the mitochondrial citrate transporter. B. It is transported out through the mitochondrial acetyl-CoA transporter. C. It is transported out using carnitine using the carnitine translocase. D. It exits the mitochondria via passive diffusion.

A. It is transported out as citrate via the mitochondrial citrate transporter.

Which of the following enzymes is responsible for controlling the triacylglycerol: phospholipid ratio AND the type of phospholipids that are synthesized? A. Phosphatidic acid phosphatase B. Phospholipase A2 C. Glycerol kinase D. AMP-PK

A. Phosphatidic acid phosphatase

The committed step of fatty acid synthesis is the formation of A. succinyl CoA B. malonyl CoA C. citrate D. oxaloacetate E. acetyl-carnitine

B. malonyl CoA

The synthesis of TGs in adipose tissue requires glycerol-3-phosphate (G3P). Which of the following are sources of G3P for TG synthesis in adipose tissue? A. glucose (via glycolysis) B. glycerol-diphosphate (following removal of a phosphate by phosphatase) C. glycerol-triphosphate (following removal of two phosphates by phosphatase) D. glycerol (following phosphorylation by glycerol kinase)

A. glucose (via glycolysis)

Phosphatidate is formed from A. glycerol 3-phosphate and two fatty acyl CoA's B. glycerol and two fatty acyl CoA's C. glycerol 3-phosphate and diacylglycerol D. pyruvate and triacylglycerol E. glycerol and two free fatty acids

A. glycerol 3-phosphate and two fatty acyl CoA's

Which of the following is the primary hormone to regulate carbohydrate and lipid metabolism in the FED state? A. insulin B. cortisol C. glucagon D. epinephrine

A. insulin

What is the key metabolite that is responsible for the coordinated regulation of fatty acid synthesis and degradation? A. malonyl-CoA B. citrate C. carnitine D. acetyl-CoA

A. malonyl-CoA

The starting materials necessary to synthesize sphingosine are A. acetyl CoA and glutamine B. palmitoyl CoA and serine C. palmitoyl CoA and aspartate D. acetyl CoA and glycine E. acetyl CoA and serine

B. palmitoyl CoA and serine

Which of the following classes of lipids may contain a ceramide? A. triacylglycerols B. sphingolipids C. glycolipids D. steroids

B, C. sphingolipids, glycolipids

Acetyl-CoA carboxylase (ACC) is inhibited by which of the following? A. citrate B. palmitoyl-CoA C. insulin D. Low energy (high AMP/ATP ratio)

B, D. palmitoyl-CoA, low energy (high AMP/ATP ratio)

How is acetyl CoA carboxylase regulated globally? A. By zymogen activation B. By the enzyme being switched off by phosphorylation and activated by dephosphorylation C. By formation of inactive fibers D. By the binding of cAMP E. By the binding of carnitine

B. By the enzyme being switched off by phosphorylation and activated by dephosphorylation

Which of the following is not required in the synthesis of fatty acids? A. Malonyl-CoA B. NADH C. Acetyl-CoA D. Biotin E. HCO3-(CO2)

B. NADH

Which of the following is not true about precursors required for fatty acid synthesis in animal cells? A. NADPH is produced in the cytosol by the pentose phosphate pathway. B. NADPH is produced in the nucleus by malic enzyme. C. Malonyl-CoA is formed in the cytosol. D. CoA is not transported across the mitochondrial membrane. E. Acetyl-CoA is transported out of the mitochondrion via the citrate shuffle.

B. NADPH is produced in the nucleus by malic enzyme.

Location for where the synthesis of fatty acids takes place in the cell A. nucleus B. cytoplasm C. ER D. lysosome E. mitochondrial matrix

B. cytoplasm

Which of the following best characterizes the activated form of diacylglycerol from which phospholipids are synthesized? A. ADP-diacylglycerol B. UDP-diacylglycerol C. CDP-diacylglycerol D. IMP-diacylglycerol E. AMP-diacylglycerol

C. CDP-diacylglycerol

In membrane lipid biosynthesis, the nucleotide ____________ is used to activate the components of the reaction. A. ATP B. UTP C. CTP D. GTP

C. CTP

Which of the following will occur in response to INCREASED phosphatidic acid phosphatase (PAP) activity? I. Production of triacylglycerols will decrease II. The identity of the phospholipids synthesized will be altered III. Production of triacylglycerols will increase A. III only B. I and II only C. II and III only D. I, II, and III E. I only

C. II and III only, the identity of the phospholipids synthesized will be altered, production of triacylglycerols will increase

What molecule is used to transport acetyl groups from the matrix to the cytoplasm? A. acetyl-carnitine B. succinyl CoA C. citrate D. a-ketoglutarate E. oxaloacetate

C. citrate

Which of the following activates fatty acid synthesis? A. palmitoyl-CoA B. phosphorylation of acetyl CoA carboxylase C. citrate D. malonyl CoA E. glucagon

C. citrate

What would be the consequences for fat metabolism of a mutation in acetyl-CoA carboxylase that replaced the Ser residue normally phosphorylated by AMPK to an Ala residue? A. Both FA oxidation and FA synthesis would be constantly on. B. FA synthesis would be inhibited, and FA oxidation would be constantly on. C. This mutation would have no effect on FA oxidation or FA synthesis. D. FA synthesis would be constantly on, and FA oxidation would be inhibited. E. Both FA oxidation and FA synthesis would be inhibited.

D. FA synthesis would be constantly on, and FA oxidation would be inhibited.

Which compound inhibits the entry of fatty acyl CoA into the mitochondria as a function of the cell being in the high-energy state? A. citrate B. mevalonate C. acetyl-CoA D. malonyl-CoA E. sphingosine

D. malonyl-CoA

Which of the following is a principal component of the lipid-rich covering on neuronal axons? A. phosphatidylserine B. cardiolipin C. triacylglycerol D. sphingomyelin E. phosphatidylinositol

D. sphingomyelin

What is the major site of triacylglycerol synthesis in mammals? A. kidney B. pancreas C. adipose tissue D. small intestine E. liver

E. liver

Coenzyme that supplies the reductive power for fatty acid synthesis A. FADH2 B. FMNH2 C. NADH D. Coenzyme A E. NADPH

E. NADPH

What metabolite is reduced to glycerol-3-phosphate for triacylglycerol synthesis? A. phosphoenolpyruvate B. glyceraldehyde-3-phosphate C. 3-phosphoglycerate D. oxaloacetate E. dihydroxyacetone phosphate

E. dihydroxyacetone phosphate (DHAP)

Place the following reactions catalyzed by fatty acid synthase (FAS) in the correct order. condensation loading dehydration hydrolysis reduction (1) reduction (2)

condensation = step 2 loading = step 1 dehydration = step 4 hydrolysis = step 6 reduction (1) = step 3 reduction (2) = step 5