Question 1

Which of the following lipoprotein profiles would be indicative of the laboratory presentation of Tangier disease?

Accepted Answer

Tangier disease (TD) is a genetic disorder characterized by severe deficiency or absence of normal HDL in plasma due to increased catabolism and the accumulation of cholesteryl esters in many tissues throughout the body.

Question 2

Which of the following statements is true of fat absorption?

Accepted Answer

In the intraluminal phase, dietary fats are modified both physically and chemically before absorption.During the transport phase, absorbed lipids are carried from the mucosal cell to other tissues through the lymphatics and blood.During the cellular phase, digested material enters intestinal mucosal cells, where it is reassembled into its preabsorptive form.

Question 3

A patient has a triglyceride level of 234 mg/dL.This would be what when converted to mmol/L?

Accepted Answer

To convert triglyceride units from mg/dL to mmol/L, divide by 88.6.234/88.6 = 2.64 mmol/L.

Question 4

Atherosclerotic plaque formation occurs in three progressive states.What is the correct order of these stages?
1)the complicated lesion
2)the fatty streaks
3)the fibrous plaque

Accepted Answer

Atherosclerotic plaque formation occurs in three progressive stages: (1) the fatty streaks, which gradually develop into raised lesions called fatty plaques; (2) the fibrous plaque, which has a proliferation of smooth muscle cells and a collagen-rich fibrous cap that covers a lipid core lined by foam cells and surrounds an amorphous extracellular accumulation of cholesteryl esters; and (3) the complicated lesion, which can manifest calcification, hemorrhage, ulceration, and thrombosis.

Question 5

Which of the following statements is incorrect regarding apoproteins?

Accepted Answer

The incorrect statement is "Apoprotein A-1 is essential for the formation and secretion of chylomicrons." The apoprotein that is essential for the formation and secretion of chylomicrons is apoprotein B-48.Apoprotein A-1 plays an important structural role in HDL and serves as an activator of LCAT.

Question 6

Which of the following are optimal fasting levels, based on Adult Treatment Panel III guidelines?
1)total cholesterol of less than 200 mg/dL
2)LDL cholesterol of greater than 100 mg/dL
3)HDL cholesterol of less than 40 mg/dL
4)triglycerides of less than 150 mg/dL

Accepted Answer

The Adult Treatment Panel III guidelines recommend the optimal fasting levels for a fasting lipoprotein profile as a total cholesterol of less than 200 mg/dL, LDL cholesterol of less than 100 mg/dL, HDL cholesterol of greater than 40 mg/dL, and triglycerides of less than150 mg/dL.

Question 7

Which of the following enzymes catalyzes the rate-determining step of endogenous cholesterol synthesis?

Accepted Answer

3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase catalyzes the rate-determining step of the mevalonate pathway, which is crucial for cholesterol synthesis in the body.

Question 8

Which of the following components of a lipoprotein profile is most affected by a nonfasting specimen?

Accepted Answer

In a nonfasting individual, the triglycerides level should not be reported because of the potential presence of intestinally absorbed triglycerides in the blood stream.Total cholesterol and HDL cholesterol are not significantly affected by a nonfasting state and may be reported.Additionally, LDL cholesterol may be reported on a nonfasting blood sample if the level is determined by direct measurement.Calculated LDL cholesterol levels will not be accurate on nonfasting samples because the calculation is based on the triglyceride level.As a precaution, some recommend that abnormal total cholesterol and/or HDL cholesterol on nonfasting individuals be followed by a fasting lipoprotein profile.

Question 9

The following data provide laboratory evidence of which lipoprotein abnormality?
Total cholesterol - decreased, triglycerides - decreased
Apoprotein B - decreased
Vitamin E - decreased
Red blood cell morphology - acanthocytosis

Accepted Answer

Patients with abetalipoproteinemia have undetectable plasma concentrations of LDL cholesterol and apoB.The plasma cholesterol concentration does not exceed 80mg/dL and is likely to be no higher than 30mg/dL.This is accompanied by concentrations of triglycerides lower than those seen in any other disease-usually < 20mg/dL.After a fat load, chylomicrons do not appear in plasma.Patients with abetalipoproteinemia suffer from fat malabsorption (steatorrhea) and low vitamin E concentrations.Vitamin E is essential for neurological function and is transported in plasma in association with the apoB-containing lipoproteins.Acanthocytosis is found in abetalipoproteinemia, with acanthocytes comprising 50% to 100% of circulating erythrocytes.The acanthocytosis found in ABL could be a result of either vitamin E deficiency or an altered membrane lipid composition.

Question 10

A plasma sample with triglycerides at a level of 100 mg/dL is expected to have a ______ appearance, a level of 175 mg/dL is expected to have a ______ appearance, and a level of 350 mg/dL is expected to have a ______ appearance.

Accepted Answer

If the plasma is clear, the triglyceride concentration is most likely to be either normal or near normal (<200 mg/dL).When triglyceride increases to about 300 mg/dL or higher, the plasma is usually hazy to turbid in appearance and is not translucent enough to allow for clear reading of newsprint through the tube.When plasma triglyceride is > 1000 mg/dL, the plasma is usually opaque and milky.

Question 11

The National Institutes of Health National Cholesterol Education Program Adult Treatment Panel III Guidelines recommend which of the following series of tests should be included in a lipoprotein profile on all adults 20 years and older every 5 years.

Accepted Answer

The National Institutes of Health National Cholesterol Education Program Adult Treatment Panel III Guidelines recommend that all adults 20 years or older have a fasting lipoprotein profile every 5 years.The fasting profile should include total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides.

Question 12

Which plasma lipoprotein has the following physical and chemical characteristics?
Electrophoretic mobility - pre-beta
Cholesterol composition - 22%
Triglycerides composition - 52%
Phospholipid composition - 18%
Apoprotein - 2%

Accepted Answer

VLDL is a lipoprotein complex made up of approximately 22% cholesterol, 52% triglycerides, 18% phospholipids, and 2% apoproteins.VLDL migrates in the pre-beta region electrophoretically and is sometimes referred to as pre-beta lipoprotein.There is some similarity between VLDL and chylomicrons because the major lipid in both lipoprotein complexes is triglyceride.The primary difference between these two lipoproteins is that triglycerides make up approximately 82% of the lipids and proteins in chylomicrons and 52% of the lipids and proteins in VLDL.Additionally, the two lipoproteins show different electrophoretic mobility.

Question 13

Cholesterol is essential for normal functioning of the body because
1)it is an essential structural component of cell membranes.
2)it is an important source of immediate energy for the heart and brain.
3)it is an important precursor of bile acids.

Accepted Answer

Cholesterol is essential for normal functioning of the body because it is an essential structural component of the membranes in the body, and it is an important precursor of bile acids.In addition, cholesterol serves as a precursor of all steroid hormones, including sex and adrenal hormones.

Question 14

During fasting, the blood glucose concentration is expected to ______, insulin concentration is expected to ______, and hepatic VLDL triglyceride synthesis is expected to ______.

Accepted Answer

Hepatic triglyceride synthesis is accelerated when the diet is rich in excess calories, and VLDL is overproduced, which may explain the hypertriglyceridemia observed when diets are particularly rich in simple sugars.During fasting, however, the metabolic pathways in the liver are reversed.Blood glucose concentration falls, insulin concentrations are diminished, and hepatic VLDL triglyceride synthesis is diminished.

Question 15

At birth, serum cholesterol levels are approximately ______, and the level steadily increases with age at a rate of approximately ______ per year.

Accepted Answer

Serum cholesterol concentration starts out around 65 mg/dL at birth and steadily increases with age at a rate of about 1.5 mg/dL per year.

Question 16

Dietary-derived and newly synthesized hepatic triglycerides are coupled with which of the following to form VLDL?

Accepted Answer

Dietary-derived and newly synthesized hepatic triglycerides are coupled with phospholipid, cholesterol, and proteins in the liver to form VLDL.

Question 17

The following laboratory data is associated with which lipoprotein electrophoretic pattern?
Standing plasma test - normal
Total cholesterol - 3+ increase
Triglycerides - normal

Accepted Answer

The laboratory data show a significant increase in total cholesterol.Cholesterol is primarily transported in the blood stream by LDL.In lipoprotein electrophoresis, LDL appears in the beta region, resulting in the increase in beta lipoprotein.LDL is also known as beta lipoprotein.

Quiz 37: Coronary Artery Disease: Lipid Metabolism

Which of the following lipoprotein profiles would be indicative of the laboratory presentation of Tangier disease?

Which of the following statements is true of fat absorption?

A patient has a triglyceride level of 234 mg/dL.This would be what when converted to mmol/L?

Atherosclerotic plaque formation occurs in three progressive states.What is the correct order of these stages? 1) the complicated lesion 2) the fatty streaks 3) the fibrous plaque

Which of the following statements is incorrect regarding apoproteins?

Which of the following are optimal fasting levels, based on Adult Treatment Panel III guidelines? 1) total cholesterol of less than 200 mg/dL 2) LDL cholesterol of greater than 100 mg/dL 3) HDL cholesterol of less than 40 mg/dL 4) triglycerides of less than 150 mg/dL

Which of the following enzymes catalyzes the rate-determining step of endogenous cholesterol synthesis?

Which of the following components of a lipoprotein profile is most affected by a nonfasting specimen?

The following data provide laboratory evidence of which lipoprotein abnormality? Total cholesterol - decreased, triglycerides - decreased Apoprotein B - decreased Vitamin E - decreased Red blood cell morphology - acanthocytosis

A plasma sample with triglycerides at a level of 100 mg/dL is expected to have a appearance, a level of 175 mg/dL is expected to have a appearance, and a level of 350 mg/dL is expected to have a __ appearance.

The National Institutes of Health National Cholesterol Education Program Adult Treatment Panel III Guidelines recommend which of the following series of tests should be included in a lipoprotein profile on all adults 20 years and older every 5 years.

Which plasma lipoprotein has the following physical and chemical characteristics? Electrophoretic mobility - pre-beta Cholesterol composition - 22% Triglycerides composition - 52% Phospholipid composition - 18% Apoprotein - 2%

Cholesterol is essential for normal functioning of the body because 1) it is an essential structural component of cell membranes. 2) it is an important source of immediate energy for the heart and brain. 3) it is an important precursor of bile acids.

During fasting, the blood glucose concentration is expected to , insulin concentration is expected to , and hepatic VLDL triglyceride synthesis is expected to __.

At birth, serum cholesterol levels are approximately , and the level steadily increases with age at a rate of approximately per year.

Dietary-derived and newly synthesized hepatic triglycerides are coupled with which of the following to form VLDL?

The following laboratory data is associated with which lipoprotein electrophoretic pattern? Standing plasma test - normal Total cholesterol - 3+ increase Triglycerides - normal