Lipids (Chemistry)

Question 1

High levels of which lipoprotein class are associated with decreased risk of accelerated atherosclerosis?

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

Answer 1

D) HDL

Question 2

The most consistent analytical error involved in the routine determination of HDL-cholesterol is caused by:

A) incomplete precipitation of LDL-cholesterol
B) precipitation of HDL-mand LDL cholesterol
C) inaccurate protein estimation of HDL-cholesterol
D) a small concentration of apoB-containing lipoproteins after precipitation

Answer 2

D) a small concentration of apoB-containing lipoproteins after precipitation

Question 3

If the LDL-cholesterol is to be calculated by the Friedewald formula, what are the 2 measurements that need to be carried out by the same chemical procedure?

A) total cholesterol and HDL-cholesterol
B) total cholesterol and triglyceride
C) triglyceride and chylomicrons
D) apolipoprotein A and apolipoprotein B

Answer 3

A) total cholesterol and HDL-cholesterol

Question 4

The chemical composition of HDL-cholesterol corresponds to:
A) triglyceride: 60%, cholesterol: 15%, protein: 10%
B) triglyceride: 10%, cholesterol: 45%, protein: 25%
C) triglyceride: 5%, cholesterol: 45%, protein: 50%
D) triglyceride: 85%, cholesterol: 5%, protein: 2%

Answer 4

C) triglyceride: 5%, cholesterol: 45%, protein: 50%

Question 5

In familial hypercholesterolemia, the hallmark finding is an elevation of:

A) low-density lipoproteins
B) chylomicrons
C) high-density lipoproteins
D) apolipoprotein A1

Answer 5

A) low-density lipoproteins

Question 6

Premature atherosclerosis can occur when which of the following becomes elevated?

A) chylomicrons
B) prostaglandins
C) low-density lipoproteins
D) high-density lipoproteins

Answer 6

C) low-density lipoproteins

Question 7

Transportation of 60-75% of the plasma cholesterol is performed by:

A) chylomicrons
B) very low-density lipoproteins
C) low-density lipoproteins
D) high-density lipoproteins

Answer 7

C) low-density lipoproteins

Question 8

Which of the following diseases results from a familial absence of high density lipoprotein?

A) Krabbe disease
B) Gaucher disease
C) Tangier disease
D) Tay-Sachs disease

Answer 8

C) Tangier disease

Question 9

A 1-year-old girl with a hyperlipoproteinemia and lipoprotein lipase deficiency has the following lipid profile:

Cholesterol: 300 mg/dL (7.77 mmol/L)
LDL: increased
HDL: decreased
triglycerides: 12000 mg/dL (13.56 mmol/L)
chylomicrons: present

A serum specimen from this patient that was refrigerated overnight would most likely be:

A) clear
B) cloudy
C) creamy layer over cloudy serum
D) creamy layer over clear serum

Answer 9

D) creamy layer over clear serum

Question 10

Which of the following lipid results would be expected to be falsely elevated on a serum specimen from a non-fasting patient?

A) cholesterol
B) triglyceride
C) HDL
D) LDL

Answer 10

B) triglyceride

Question 11

A 9-month old boy from Israel has gradually lost the ability to sit up, and develops seizures. He has an increased amount of a phospholipid called GM2-ganglioside in his neurons, and he lacks the enzyme hexosaminidase A in his leukocytes. These findings suggest:

A) Neimann-Pick disease
B) Tay-Sachs disease
C) phenylketonuria
D) Hurler syndrome

Answer 11

B) Tay-Sachs disease

Question 12

In amniotic fluid, the procedure used to determine fetal lung maturity is:

A) lecithin/sphingomyelin ratio
B) creatinine
C) measurement of absorbance at 450 nm
D) alpha-fetoprotein

Answer 12

A) lecithin/sphingomyelin ratio

Question 13

The class of phospholipid surfactants represented by the dotted line on the amniotic fluid analysis shown above is thought to originate in what fetal organ system?

A) cardiovascular
c
C) hepatic
D) placental

Answer 13

A) lecithin/sphingomyelin ratio

Question 14

A fasting serum sample from an asymptomatic 43-year-old woman is examined visually and chemically with the following results:

initial appearance of serum: milky
appearance of serum after overnight refrigeration: cream layer over turbid serum
triglyceride level: 2000 mg/dL (22.6 mmol/L)
cholesterol level: 550 mg/dL (14.25 mmol/L)

This sample contains predominantly:

A) chylomicrons, alone
B) chylomicrons and very low-density lipoproteins (VLDL)
C) very low-density lipoproteins (VLDL) and low-density lipoproteins (LDL)
D) high-density lipoproteins (HDL)

Answer 14

B) chylomicrons and very low-density lipoproteins (VLDL)

Question 15

Chylomicrons are present in which of the following dyslipidemias?

A) familial hypercholesterolemia
B) hypertriglyceridemia
C) deficiency in lipoprotein lipase activity
D) familial hypoalphalipoproteinemia

Answer 15

C) deficiency in lipoprotein lipase activity

Question 16

The function of the major lipid components of the very low-density lipoproteins (VLDL) is to transport:

A) cholesterol from peripheral cells to the liver
B) cholesterol and phospholipids to peripheral cells
C) exogenous triglycerides
D) endogenous triglycerides

Answer 16

D) endogenous triglycerides

Question 17

Turbidity in serum suggests elevation of:

A) cholesterol
B) total proteins
C) chylomicrons
D) albumin

Answer 17

C) chylomicrons

Question 18

A lipemic serum is separated and frozen at -20 degrees C for assay at a later date. One week later, prior to performing an assay for triglycerides, the specimen should be:

A) warmed to 37 degrees C and mixed thoroughly
B) warmed to 15 degrees C and centrifuged
C) transferred to a glycerated test tube
D) discarded and a new specimen obtained

Answer 18

A) warmed to 37 degrees C and mixed thoroughly

Question 19

As a part of a hyperlipidemia screening program, the following resutls were obtained on a 25-year-old woman 6 hours after eating:

Triglycerides: 260 mg/dL (2.86 mmol/L)
Cholesterol: 120 mg/dL (3.12 mmol/L)

Which of the following is the best interpretation of these results?

A) both results are normal, and not affected by the recent meal
B) cholesterol is normal, but triglycerides are elevated, which may be attributed to the recent meal
C) both results are elevated, indicating a metabolic problem in addition to the nonfasting state
D) both results are below normal despite the recent meal, indicating a metabolic problem

Answer 19

B) cholesterol is normal, but triglycerides are elevated, which may be attributed to the recent meal

Question 20

Blood was collected in a serum separator tube on a patient who has been fasting since midnight. The time of collection was 7 am. The laboratory test which should be recollected is:

A) triglycerides
B) iron
C) LD
D) sodium

Answer 20

A) triglycerides

Question 21

Which of the following is the formula for collecting absorbance given the percent transmittance (%T) of a solution?

A) 1-log(%T)
B) log(%T)/2
C) 2 x log(%T)
D) 2 - log(%T)

Answer 21

D) 2 - log(%T)

Question 22

The substance that is measured to estimate the serum concentration of triglycerides by the most methods is:

A) phospholipids
B) glycerol
C) fatty acids
D) pre-beta lipoprotein

Answer 22

B) glycerol

Question 23

Which of the following methods for quantitation of high-density lipprotein is most suited for clinical laboratory use?

A) Gomori procedure
B) homogeneous
C) column chromatography
D) agarose gel electrophoresis

Answer 23

B) homogeneous