Lipid Biosynthesis

In FA synthase, the correct sequence of enzyme catalyzed reactions are: A. Beta-ketoacyl-ACP synthase B. Beta-ketoacyl reductase C. Beta-hydroxyacyl dehydratase D. Enoyl reductase E. Acetyl Transferase

A B C D E

Order the lipoproteins from lowest density to highest density a. chylomicrons b. HDL c. IDL d. VLDL e. LDL

A D C E B

The reaction catalyzed by ___ is: Citrate + ATP + CoA —-> Acetyl CoA + ___ + ____ A. Citrate synthase; malate; AMP + Pi B. Citrate synthase; OAA; AMP + PPi C. ATP-citrate lyase; OAA; AMP + PPi D. ATP-Citrate lyase; OAA; ADP + Pi E. Citrate synthase; OAA; ADP + Pi

D. ATP - citrate lyase; OAA: ADP + Pi

Acetyl-CoA carboxylase in animals is regulated by all EXCEPT A. Allosterically stimulated by citrate B. Phosphorylation by pKA C. Allosteric inhibition by palmitoyl CoA D. Allosterically stimulated by ATP E. All are correct

D. Allosterically stimulated by ATP

Which of the following is correctly paired with its effect upon FA synthesis A. Palmitoyl CoA; activates B. Glucagon; activates C. Insulin; inhibits D. Citrate; activates E. NADPH; inhibits

D. Citrate; activates

The carbons of sphinganine are derived from: A. Palmitate and glycerol B. Arachidonate and glycine C. Fatty alcohol and dihydroxyacetone phosphate (DHAP) D. Palmitate and serine E. None

D. Palmitate and serine

E. Coli does NOT Have any ____ FA, plants can introduce double bonds in FA between delta 9 and the ____ - end of the chain, while mammals can only introduce double bonds between delta 9 and the ____ - end of the chain A. Saturated; carboxyl; methyl B. Mono-unsaturated; carboxyl; methyl C. Polyunsaturated; carboxyl; methyl D. Polyunsaturated; methyl; carboxyl E. Saturated; methyl; carboxyl

D. Polyunsaturated; methyl; carboxyl

The appropriate sequence of intermediates between mevalonate and squalene are: A. geranyl pyrophosphate B. isopentenyl pyrophosphate C. 5-phosphomevalonate D. farnesyl pyrophosphate E. dimethylallyl pyrophosphate

C B E A D

The correct sequence for the synthesis of mevealonate from acetyl CoA is: A. HMG-CoA synthase B. Formation of 3-hydroxybutyrate-3-methylglutaryl-CoA C. Beta-keto thiolase catalyzed condensation D. HMG -CoA reductase activity E. Formation of acetoacetyl-CoA

C E A B D

The major circulatory complex for cholesterol and cholesterol esters that is often referred to a "bad cholesterol" is the: a. chylomicrons. b. HDL. c. IDL. d. VLDL. e. LDL.

LDL

Insulin promotes the ____ of acetyl-CoA carboxylase and ____ of TAG lipase by ____ the phosphodiesterases that convert cAMP to AMP A. Activation; inactivation; stimulating B. Inactivation; activation; stimulating C. Inactivation; activation; inhibiting D. Activation; inactivation; inhibiting E. None are true

A. Activation; inactivation; stimulating

All are characteristics of arachidonic acid EXCEPT A. It contains 5 cis double bonds B. It is a precursor of leukotrienes and most prostaglandins C. It is an omega 6 FA D. It can be synthesized from linoleic acid in mammals E. All are correct

A. It contains 5 cis double bonds

The formation of acetoacetyl-ACP is catalyzed by: A. Beta-ketoacyl ACP synthase (KSase) B. Acetyl-CoA carboxylase C. Acetyl Transacylase D. Beta-hydroxyacyl dehydratase E. Beta-ketoacyl reductase

A. KSase

Reducing equivalents derived from glycolysis in the form of NADH can be transformed into ____ for FA biosynthesis by the combined actions of ____ & _____ A. NADPH; malate dehydrogenase; malic enzyme B. NADPH; malate dehydrogenase; malic enzyme C. ATP; malate dehydrogenase; malic enzyme D. NADH ; glyceraldehyde 3 P dehydrogenase; malate dehydrogenase E. NADPH; Glyceraldehyde 3 P dehydrogenase ; malate enzyme

A. NADPH; malate dehydrogenase; malic enzyme

CDP-diacylglycerols are precursors fro the synthesis of all EXCEPT: A. Phosphatidylethanolamine B. Phosphatidyl glycerol C. Cardiolipins D. Phosphatidylinositol E. All are true

A. Phosphatidylethanolamine

FAS (fatty acid synthase) differs from beta-oxidation in all of the following ways EXCEPT: A. Occurs in cytosol B. Uses NADPH for oxidoreductase reactions C. Acyl carrier protein linked intermediates D. All of the enzymes are on one polypeptide E. All are true

All are true

Sphinganine is acylated in the _____ - position A. 3-OH B. 2-NH2 C. 1-OH D. 3-NH2 E. All are true

B. 2-NH2

In e-coli, beta hydroxydecanoyl-ACP is dehydrated by beta-hydroxydecanoyl thioester dehydrase to form a double bond ____ to the thioester in the ____ configuration which is further elongated to form ____ A. Alpha, beta; cis; palmitoyl-ACP B. Beta; gamma; cis; palmitoleoyl ACP C. Beta, gamma; trans; palmitoyleoyl ACP D. Alpha, beta; trans; palmitoleoyl-ACP E. Beta, gamma; cis; palmitoyl-ACP

B. Beta, gamma; cis; palmitoleoyl-ACP

Platelet-activating factor displays dramatic ability to ____ BV and thus ______ BP, and to aggregate platelets A. Dilate; reduce B. Dilate; reduce C. Constrict; increase D. Constrict; increase E. Constrict; increase

B. Dilate; reduce

All are regulatory mechanisms of HMG-CoA reductase except: A. Low (cholesterol) increases mRNA for HMG-CoA reductase B. High (cholesterol) increases half life for HMG-CoA reductase C. High (cholesterol) results in lower mRNA for HMG-CoA reductase D. Phosphorylation by cAMP cascade inactivates HMG-CoA reductase E. Phosphatase activate HMG-CoA reductase

B. High (cholesterol) increases half life for HMG-CoA reductase

Stearoyl-CoA desaturate has all the following characteristics EXCEPT: A. NADH and O2 are required B. Produces a trans double bond C. Involves cytochrome b5 reductase D. Involves cytochrome b5 E. Occurs in the ER

B. Produces a trans double bond

What type of linkage occurs between ACP and the intermediates in FA biosynthesis? A. An ester B. A thioester C. An amide D. An ether E. An acetal

B. Thioesters

Both glycerol and DHAP can serve as precursors for phosphatidic acid. Which enzyme is NOT USED to catalyze the reactions in the synthesis of phosphatidic acid from these two precursors? A. Glycerol kinase B. Triose phosphate isomerase C. Acyl dihydroxyacetone P reductase D. Glycerol 3 phosphate acyltransferase E. 1-acylglycerol-3-phosphate acyltransferase

B. Triose phosphate isomerase

There is no transporter for acetyl-CoA to exit the mitochondria, so the carbons must be converted to ____ for transport to the cytosol A. Acetone B. Butyrate C. Citrate D. Pyruvate E. Malonate

C. Citrate

Phosphorylation of regulatory sites on acetyl-CoA carboxylase ___ the affinity for citrate and ____ the affinity for fatty acyl-CoAs requiring ____ levels of fatty acyl-CoAs for inhibition A. Increases; decreases;low B. Decreases; increases; high C. Decreases;increases;low D. Increase;decreases;high E. None

C. Decreases; increases; low

The committed step in cholesterol biosynthesis is catalyzed by: A. HMG-CoA synthase B. Mevalonate kinase C. HMG-CoA reductase D. Squalene monooxygenase E. HMG-CoA lyase

C. HMG-CoA reductase

All are true for aspirin EXCEPT : A. It does not affect the peroxidase activity of prostaglandin endoperoxide synthase (COX) B. It inhibits the activity of prostaglandin endoperoxide synthase (COX) C. It stimulates ring opening in prostaglandin synthesis D. It acetyl ATPs the serine in the active site of the cyclooxygenase (COX) E. It is classed as a non-steroidal anti-inflammatory drug (NSAID)

C. It stimulates ring opening in prostaglandin synthesis

The main source(s) for NADPH for FA biosynthesis is (are): A. TCA cycle B. Oxidative phosphorylation C. Malic enzyme and the PPP D. The conversion of OAA to malate by malate dehydrogenase E. Glycolysis

C. Malic enzyme and the PPP

A lipid that does NOT have a sphingosine backbone is: A. Ganglioside GM1 B. Sphingomyelin C. Phosphatidylinositol D. Ceramide E. Cerebroside

C. Phosphatidylinositol

Which of the following is true regarding FA elongation? A. Malonyl CoA provides 2 carbons for each round of elongation B. Two reductions take place with both reactions using NADPH as the source of electrons C. The FA that is being elongated is attached to CoA D. Occurs only in cytosol E. By not performing the second reduction rxn, an unsaturated FA with a cis double bond can be formed

C. The FA that is being elongated is attached to CoA

In eukaryotes, phosphatidic acid is converted directly either to ___ or to ____ fromwhich all other _____ are derived A. TAG; monoacylglycerols ; acylglycerols B. Acylglycerols; phospholipids; glycerophospholipds C. Monoacylglycerols ; phospholipids; glycerophospholipids D. Diacylglycerols; CDP-diacylglycerols; glycerophospholipids E. Diacylglycerols; CDP-diacylglycerols; acylglycerols

D. Diacylglycerols; CDP-diacylglycerols; glycerophospholipids

_______ are all derived from 20-C FA that are acylated to membrane phospholipids and released by the enzyme ______ A. Arachidonates; TAG lipase B. Arachidonates; phospholipase A1 C. Eicosanoids; phospholipase A1 D. Eicosanoids; phospholipase A2 E. Arachidonates; phospholipase A2

D. Eicosanoids; phospholipase A2

An important mechanism of arachidonate release and eicosanoid synthesis involves _____ and ______ A. Insulin release; high blood sugar B. Glucagon release; low blood sugar C. Tissue injury; low blood sugar D. Inflammation; tissue injury E. All are true

D. Inflammation ; tissue injury

Regulation of FA synthesis in humans is affected by all EXCEPT A. Malonyl-CoA binding to carnitine acyltransferase inhibits available substrate for beta-oxidation B. Citrate stimulates acetyl-CoA carboxylase C. Acyl-CoAs are inhibitors of acetyl-CoA carboxylase D. Insulin receptor binding maintains acetyl-CoA carboxylase in the inactive form E. Glucagon promotes phosphorylation and inactivation of acetyl CoA carboxylase

D. Insulin receptor binding maintains acetyl CoA carboxylase in the inactive from

the PRIMARY site, but not the only site, of cholesterol synthesis is: A. Heart B. Intestine C. Muscle D. Liver E. Adipose

D. Liver

All are characteristics of acetyl CoA carboxylase EXCEPT: A. Allosteric inhibition by palmitoyl-CoA B. Biotin carboxylase and transcarboxylase subunits C. Biotin carboxyl carrier protein subunits D. Citrate shits the enzyme toward the active polymer E. All are correct

E. All are correct

All are characteristics of COX2 inhibitors EXCEPT A. Selectively block inflammation mediated by COX2 B. Are NSAIDs C. Less potential for stomach lesions than aspirin D. Less renal toxicity than COX 1 inhibitors E. All are true

E. All are true

The coenzymes of acetyl CoA carboxylase is/are A. Biotin and NAD+ B. TPP C. NADH and FAD D. TPP and folic acid E. Biotin

E. Biotin

Which of the following regarding phosphorylation of acetyl-CoA carboxylase is correct? A. Phosphorylation causes activation only in the presence of palmitoyl-CoA B. Phosphorylation is a result of glucagon binding to its receptor C. High (citrate) inhibits the phosphorylated form D. Phosphorylation causes separation of the polymeric form of the enzyme to inactive protomers E. Both b and d

E. Both b and d are correct

Components for plasmalogen biosynthesis includes all except: A. CDP-ethanolamine B. Fatty acyl CoA C. NADPH, NADH, and O2 D. Long chain alcohol E. Glycerol

E. Glycerol

Which of all the following statements concerning eicosanoids is correct? A. All thromboxanes contain a 1,3-dioxane ring B. All prostaglandins contain a cyclic ether C. All leukotrienes contain 3 conjugated double bonds D. Leukotrienes are derived from prostaglandin H2 while thromboxanes are derived from arachidonic acid E. None

E. None

Acyl-Carrier protein has the same ____ group as the 'business end' of ____ A. Thiamine; TPP B. Biotin;acetyl-CoA carboxylase C. Phosphoadenosine; cAMP D. Pyridoxal phosphate; vitamin B6 E. Phosphopantetheine; CoA

E. Phosphopantetheine; CoA

Which of the following CANNOT be made from acetyl CoA? a. cholesterol b. pyruvate c. acetoacetate d. squalene e. palmitate

b. pyruvate

Which of the following catalyzes the conversion of cholesterol to pregnenolone, the first step in the conversion of cholesterol to steroid based hormones? a. 7-alpha-hydroxylase b. desmolase c. steroid 5-alpha-reductase d. aromatase e. 17-ketoreductase

a. 7-alpha-hydroxylase

Which of the following lipoproteins is INCORRECTLY defined? a. chylomicron: transport of dietary lipids to the liver b. HDL: scavenger of extra-hepatic cholesterol c. LDL: transport of cholesterol to extra-hepatic tissue d. VLDL: transport of triacylglycerols from the liver e. all of the above are correct

a. chylomicron: transport of dietary lipids to the liver

Dietary lipids are "packaged" in the intestine into ____ for transport via the lymphatic system. a. chylomicrons b. HDL c. IDL d. VLDL e. LDL

a. chylomicrons

HMG-CoA reductase, the regulatory enzyme for the synthesis of cholesterol, is inhibited by simvastatin. Based upon the structure of the product, mevalonate, and the structure of simvastatin, what sort of enzyme inhibition would be produced by simvastatin? a . competitive b. non-competitive c. uncompetitive d. mechanism-based inactivator e. none of the above

a. competitive

Which of the following is FALSE regarding HDL pariticales? a. high HDL levels correlates with high risk of cardiovascular disease. b. an HDL life span is typically 5 to 6 days. c. they are initially formed as HDL precursors that contains no cholesterol or cholesterol esters. d. scavenges excess cholesterol from extrahepatic tissue and returns cholesterol and cholesterol esters to liver. e. accumulates cholesterol esters via LCAT action.

a. high HDL levels correlates with high risk of cardiovascular disease.

____ is an intermediate on the biosynthetic pathway from cholesterol to both male and female hormones. a. Aldosterone b. Progesterone c. Cortisol d. Estradiol e. Testosterone

b. Progesterone

Which of the following is correctly paired with its precursor? a. cholesterol --> palmitic acid b. arachidonic acid --> prostaglandins c. testosterone --> progesterone d. aldosterone --> cholic acid e. none of the above

b. arachidonic acid --> prostaglandins

Lipoproteins consist of a core of ____ and ____ surrounded by a single layer of ____, into which is inserted ____ and ____. a. proteins; triacylglycerols; cholesterol esters; phospholipids; cholesterol b. triacylglycerols; cholesterol esters; phospholipids; proteins; cholesterol c. phospholipids; cholesterol esters; triacylglycerols; proteins; cholesterol d. cholesterol esters; proteins; cholesterol; phospholipids; triacylglycerols e. triacylglycerols; cholesterol; proteins; cholesterol esters; phospholipids

b. triacylglycerols; cholesterol esters; phospholipids; proteins; cholesterol

How many NADPH are required to make one molecule of palmitic acid from acetyl CoA? a. 7 b. 8 c. 14 d. 16 e. 21

c. 14

The role of citrate in fatty acid synthesis makes it an important regulator of the process. Which of the following enzymes would be allosterically activated by citrate? a. Citrate lyase b. Malic enzyme c. Acetyl-CoA carboxylase d. beta-ketoacyl-ACP synthase e. None of the above

c. Acetyl-CoA carboxylase

Which of the following statements is true regarding lipid metabolism? a. The synthesis of one molecule of cholesterol requires 5 molecules of mevalonate b. The synthesis of fatty acids from acetyl CoA involves reduction by NADPH and FADH2 c. Synthesis of fatty acids involves a coordinated effort of fatty acid synthase complex and the acyl carrier protein d. The conversion of lanosterol to cholesterol requires only 4 steps, two that remove methyl groups, an isomerization, and a reduction e. The synthesis of fatty acids involves a series of reactions catalyzed by several separate enzymes, thus requiring the substrates to diffuse from one enzyme to the next

c. Synthesis of fatty acids involves a coordinated effort of fatty acid synthase complex and the acyl carrier protein

The "statins" are a series of drugs used to: a. inhibit fatty acid synthesis in diet drugs. b. widely prescribed drugs used to inhibit squalene monooxygenase. c. derivatives or mimics of mevinolin used to inhibit HMG-CoA reductase. d. derivatives of cholesterol used to lower cholesterol levels. e. none are true.

c. derivatives or mimics of mevinolin used to inhibit HMG-CoA reductase

Male baldness, prostate hyperplasia and prostate cancer have been implicated in elevated levels of ____ and treatment involves inhibition of ____. a. glucocorticoids; gluconeogenesis b. stanozolol; lactate dehydrogenase c. dihydrotestosterone; steroid 5alpha-reductase d. cholesterol; mevinolin e. none of the above

c. dihydrotestosterone; steroid 5alpha-reductase

Which of the following molecules would have an inhibitory effect upon the overall process of fatty acid synthesis? a. citrate b. insulin c. palmitoyl CoA d. NADPH e. none of the above

c. palmitoyl CoA

Lipoprotein lipase hydrolyzes ____ from VLDL particles to convert the VLDL into ____. a. cholesterol esters; HDL particles b. cholesterol esters; LDL particles c. triacylglycerols; LDL particles d. triacylglycerols; chylomicrons e. triacylglycerols; HDL particles

c. triacylglycerols; LDL particles

The committed step in FA biosynthesis, formation of malonyl-CoA is catalyzed by: A. FA synthase B. Pyruvate carboxylase C. Propionate carboxylase D. Acetyl CoA carboxylase E. ATP citrate lyase

d. Acetyl CoA carboxylase

The general genetic defect responsible for ____ is the absence or dysfunction of ____ in the body such that blood cholesterol levels are typically 300 to over 800 mg/dL. a. hypocholesterolemia; triacylglycerol lipase b. hypercholesterolemia; lipoprotein lipase c. LCAT; LDL receptors d. familial hypercholesterolemia; LDL receptors e. familial hypocholesterolemia; HDL receptors

d. familial hypercholesterolemia; LDL receptors

Characteristics of mixed-function oxidases include all EXCEPT: a. usually involve cytochrome P-450. b. often catalyze hydroxylation reactions on ring-systems such as sterols. c. use both NADPH and O2. d. one product is CO2. e. all are correct.

d. one product is CO2.

All are true for the action of cortisol EXCEPT: a. stimulates gluconeogenesis and glycogen synthesis in liver. b. inhibits protein synthesis and stimulates protein degradation in muscle. c. inhibits allergic and inflammatory responses. d. exerts an immunosuppressive effect and an inhibition of wound healing. e. all are true.

e. all are true

Characteristics of squalene monooxygenase include all EXCEPT: a. requires a soluble protein activator. b. bound to the endoplasmic reticulum (ER). c. uses FAD and NADPH. d. requires O 2 . e. all are true.

e. all are true

Properties of progesterone include all EXCEPT: a. produced from pregnenolone in ER. b. synthesis in the adrenal cortex activated by ACTH. c. prepares the uterus for attachment of a fertilized ovum. d. secreted from corpus luteum in late menstrual cycle. e. all are true.

e. all are true

All are correct for bile salts EXCEPT: a. made by the liver and utilized in the intestine. b. derived from cholesterol. c. conjugates of bile acids with glycine and taurine. d. highly effective as detergents. e. insert well into membranes because they are strictly nonpolar.

e. insert well into membranes because they are strictly nonpolar.