Deck 23: Lipids, lip-Oproteins, apolipoproteins, and Other Cardiac Risk Factors

Question 1

The class of lipid that is derived from fatty acids and that alters blood pressure by its action on arterial smooth muscle cells is:

A) sphingolipids.
B) acylglycerols.
C) terpenes.
D) prostaglandins.

Answer 1

prostaglandins.

Question 2

What distinguishes lipoprotein(a),or Lp(a),from LDL?

A) Lp(a)contains more core lipids,triglyceride,and cholesteryl ester and a smaller percent of protein.
B) Lp(a)interacts with ABCA1 in peripheral cells,such as the macrophages,to remove additional cholesterol.
C) Lp(a)contains a carbohydrate-rich protein called apo(a)that is covalently bound to apo B-100 through a disulfide linkage.
D) Lp(a)does not contain any apo B-100.

Answer 2

Lp(a)contains a carbohydrate-rich protein called apo(a)that is covalently bound to apo B-100 through a disulfide linkage.

Question 3

Cholesterol is esterified to form a cholesteryl ester by acylcholesterol acyltransferase in the cell.In the circulation,cholesteryl esters are formed by the action of which one of the following enzymes?

A) HMG CoA reductase
B) Cholesterol oxidase
C) Lecithin cholesterol acyltransferase
D) Fatty acid hydrolase

Answer 3

Lecithin cholesterol acyltransferase

Question 4

There is an inverse relationship between which of the following cholesterol-containing lipoproteins and increased risk of CHD?

A) VLDL
B) LDL
C) Chylomicrons
D) HDL

Question 5

Recognized abnormalities of fatty acid catabolism associated with uncontrolled diabetes mellitus include the development of ketone formation.This ketosis is caused by:

A) loss of apolipoprotein receptors on the surfaces of cells.
B) dysbetalipoproteinemia.
C) destruction of mitochondria within cells.
D) excess acetyl-CoA being diverted to form ketone bodies.

Question 6

A 46-year-old man visits his physician complaining of fatigue and chest pains.His family history reveals that his father and grandfather both died of heart attacks at the age of 50.Laboratory results indicated elevated total cholesterol,elevated low-density lipoprotein (LDL),and normal triglyceride.He is eventually diagnosed with familial hypercholesterolemia and atherosclerosis.What is the likely cause?

A) Genetic lack of LDL receptors on cell surfaces
B) Insulin deficiency
C) Lipoprotein lipase deficiency
D) Tangier disease

Question 7

In the 3-step assay for determination of cholesterol concentration,cholesteryl esters must be cleaved by an enzyme.This hydrolytic cleavage forms:

A) free triglyceride and fatty acids.
B) triglyceride and glycerol-1-phosphate.
C) cholesterol and fatty acids.
D) choles-4-en-3-one and hydrogen peroxide.

Question 8

Why would high sensitivity C-reactive protein (CRP)be an indicator of potential coronary heart disease (CHD)?

A) It is an acute phase reactant plasma protein that rises in response to inflammation,which has been demonstrated to be associated with risk of future CHD.
B) CRP levels rise because of its presence in cardiac muscle and release upon muscle cell death.
C) It is a myocardial protein that regulates muscle contraction through interaction with myosin and actin.
D) It is an enzyme found in skeletal muscle and cardiac muscle and is released upon tissue injury.

Question 9

An individual visits his physician with splenomegaly,enlarged and orange-colored tonsils,and tingling feelings in the extremities,indicating peripheral neuropathy.Upon examination of the blood smear for a white blood cell differential,many foamy-appearing cells were noted.Normal triglyceride and total cholesterol values were noted; however,a marked decrease of HDL was also noted.What is the cause of this disorder?

A) Mutations in the apo B-100 gene
B) Defects in the expression or function of the LDL receptor
C) Genetic mutations in the apo E gene
D) Mutations in the ABCA1 transporter gene

Question 10

The lipoprotein with the smallest diameter and that has a 50:50 lipid:lipoprotein ratio is the:

A) LDL.
B) chylomicron.
C) HDL.
D) VLDL.

Question 11

In the small intestine,_____ is (are)solubilized by emulsification to form micelles.

A) lipase
B) cholesterol
C) starch
D) monosaccharides

Question 12

The lipoprotein that,because it is considered proatherogenic,is often measured by the laboratory to assess the likelihood of CHD in an individual with normal lipid values but a strong family history of cardiovascular disease is:

A) LDL.
B) HDL.
C) lipoprotein(a).
D) chylomicrons.

Question 13

Essential fatty acids are:

A) straight-chain monocarboxylic acids that can be classified as unsaturated,monounsaturated,or polyunsaturated.
B) fatty acids that cannot be synthesized by the human body.
C) lipids that contain phosphorous.
D) a group of compounds derived from unsaturated 20-carbon fatty acids.

Question 14

An individual visits a physician,who notes that the patient has splenomegaly,enlarged and orange-colored tonsils,and tingling feelings in the extremities,indicating peripheral neuropathy.Upon examination of the blood smear for a white blood cell differential,many foamy-appearing cells were noted.Normal triglyceride and total cholesterol values were noted; however,a marked decrease of HDL was also noted.What is the name of this disorder?

A) Familial hypercholesterolemia
B) Tangier disease
C) Dysbetalipoproteinemia
D) Coronary heart disease

Question 15

The apolipoprotein that functions to facilitate uptake of chylomicron remnants by the liver,is involved in dysbetalipoproteinemia,and that has an isoform associated with the risk of Alzheimer disease development is apo:

A) E.
B) B-100.
C) B-48.
D) A-I.

Question 16

In the 3-step assay for determination of cholesterol concentration,cholesteryl esters must be cleaved by which of the following enzymes for the initial step to occur?

A) Cholesterol oxidase
B) Lipase
C) Peroxidase
D) Cholesteryl ester hydrolase

Question 17

A 6-year-old girl has complained about painful urination and is taken to her pediatrician.There is no family history of CHD or any lipid abnormalities.After a fasting blood specimen and urine specimen are obtained,laboratory findings are as follows (healthy reference intervals are in parentheses): serum albumin 1.8 g/dL (3.5 to 5.5 g/dL),total serum cholesterol 200 mg/dL (<170 mg/dL),LDL cholesterol 130 mg/dL (<110 mg/dL),serum triglyceride 250 mg/dL (<200 mg/dL),serum urea nitrogen 20 mg/dL (7 to 18 mg/dL),heavy urine protein (normal is negative),and 1+ urine blood (normal is negative).All other laboratory values were normal.These findings are most compatible with:

A) acute poststreptococcal glomerulonephritis with dysbetalipoproteinemia.
B) a renal disorder with secondary hyperlipidemia.
C) acute pyelonephritis and familial hypercholesterolemia.
D) mild glomerular disease with lipoprotein lipase deficiency.

Question 18

Cholesterol plays a role in all of the following except:

A) myelinization of the central nervous system.
B) steroid hormone precursor.
C) cell membrane component.
D) bile acid precursor.

Question 19

The difference between traditional HDL cholesterol assays and the direct homogeneous assay is that:

A) there is no physical separation of HDL from the non-HDL fractions and HDL is selectively measured.
B) precipitation of non-HDL lipoproteins must occur using polyanions.
C) enzymatic measurement of HDL occurs after non-HDL lipoproteins are removed by ultracentrifugation.
D) measurement of the rate of oxygen consumption occurs before removal of non-HDL lipoproteins.

Question 20

The polar amphipathic lipid that forms a surface coating around a core of cholesterol esters and triglyceride in a lipoprotein is:

A) chylomicron.
B) sphingolipid.
C) phospholipid.
D) HDL.

Question 21

The high-sensitivity detection method for CRP (hs-CRP)used to detect low concentrations of this protein is typically a(n):

A) colorimetric assay.
B) immunoassay.
C) light-scattering technique.
D) HPLC assay.

Question 22

In addition to unesterified cholesterol,what is the second constituent of the outer coating of a lipoprotein,labeled with a question mark and represented by a white circle in this diagram?

A) Protein
B) Phospholipid
C) Lipoprotein A
D) Chylomicrons

Question 23

Approximately one-third of the daily production of circulating cholesterol is converted in the liver to form:

A) bilirubin.
B) estrogen.
C) bile acids.
D) hydrochloric acid.

Question 24

What is (are)the principal apo B-100 containing lipoprotein(s)secreted by the liver?

A) LDL and VLDL
B) VLDL
C) LDL
D) HDL

Question 25

Which one of the following lipid metabolic pathways involves the removal of excess cellular cholesterol from cells and returning it to the liver for excretion?

A) Exogenous
B) Endogenous
C) Intracellular-cholesterol transport
D) Reverse-cholesterol transport

Question 26

A 9-year-old boy was referred by his dermatologist for a lipid evaluation after the boy developed what appeared to be a raised yellowish rash over his palms and elbows.The boy had no previous history of heart problems and no family history of any coronary disorders.However,when he was 8,he did have two acute attacks of pancreatitis and abdominal pain.His lipid workup is as follows (specimen was a fasting blood draw): triglyceride 3200 mg/dL (normal <200 mg/dL),total cholesterol 190 mg/dL (normal <200 mg/dL),glucose 160 mg/dL (normal 60 to 110 mg/dL).His HDL concentration was in normal range,but LDL was elevated.Specimen was grossly lipemic.What is the likely cause of these symptoms?

A) Lipoprotein lipase deficiency
B) Familial hypercholesterolemia
C) Tangier disease
D) Genetic deficiency of LDL

Question 27

The Friedewald formula is used to indirectly determine the concentration of which one of the following?

A) Triglyceride
B) Phospholipid
C) HDL cholesterol
D) LDL cholesterol

Question 28

In the intracellular-cholesterol transport pathway of lipoprotein metabolism,cholesterol homeostasis is maintained through control of cellular uptake.The LDL cell surface receptor delivers lipoprotein particles containing cholesteryl esters to lysosomes.The apolipoprotein that is recognized by this receptor is apo:

A) E.
B) C-II.
C) B-100.
D) A2.

Question 29

The major component of a lipoprotein that functions to maintain the structural integrity of the lipoprotein complex and that modulates the activity of the enzymes that act on lipoproteins is the:

A) apolipoprotein.
B) phospholipid.
C) lipid core.
D) lipoprotein lipase.

Question 30

You have received two blood samples,one in a sodium citrate tube for coagulation studies and the other in an oxalate tube for glucose analysis from a patient diagnosed with diabetes mellitus.This patient's physician contacts you to request that lipid and lipoprotein analyses be added to the previous studies.What would be the best blood specimen for lipoprotein analyses and why?

A) The submitted specimens (citrate and oxalate)would be the most appropriate to use for lipoprotein analysis.
B) Ethylenediaminetetraacetic acid (EDTA)anticoagulant would be best because it inhibits the oxidation of lipids.
C) A special yellow-top tube must be used for lipoprotein analysis because it contains a special anticoagulant that maintains the integrity of the lipoproteins.
D) Serum would be best because it has no osmotic effects on cells and current cut points are based on serum values.