Elsevier Flashcards
(20 cards)
Which of the following is considered a lipid?
a. Chylomicrons
b. LDL
c. Cholesterol
d. HDL
C. Chylomicrons, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) are considered to be lipoproteins that transport lipids throughout the body; cholesterol is classified as a lipid.
In the laboratory procedure for the quantification of HDL, the purpose of the dextran sulfate is to:
a. Precipitate all Apo A1 containing lipoproteins
b. Covert cholesterol esters to cholesterol for detection
c. Precipitate all Apo B and Apo A containing
lipoproteins
d. Precipitate all Apo B containing proteins
d. Dextran sulfate precipitates all Apo B–containing lipoproteins (chylomicrons, very-low-density lipoprotein [VLDL], intermediate density lipoprotein [IDL], and low-density lipoprotein [LDL]) leaving high-density lipoprotein (HDL) (Apo A–containing lipoprotein) in the supernatant. HDL is then mixed with the reagent cholesterol esterase and cholesterol oxidase to
quantitate HDL concentrations.
Which of the following lipoproteins is the smallest of
all the lipoproteins and is composed of 50% protein?
a. HDL
b. Chylomicrons
c. LDL
d. Triglycerides
a. Lipoproteins are characterized by size and density. High-density lipoprotein (HDL) is the smallest, most dense lipoprotein, carrying 50% of its weight as protein.
Which of the following would be most adversely
affected by a nonfasting sample?
a. HDL
b. LDL
c. Cholesterol
d. Triglycerides
d. Triglycerides are most adversely affected by recent food intake, and therefore a fast is always recommended for triglyceride analysis.
Which of the following apoproteins is responsible for
receptor binding for IDL and the chylomicron remnant
produced in fat transport?
a. Apo A1
b. Apo C
c. Apo E
d. Apo B
c. Apo E is a ligand for the low-density lipoprotein
(LDL) receptor, reverses cholesterol transport,
and is a regulator of cell growth and immune
responses.
Which of the following enzymes is found bound to
HDL and LDL in blood plasma and acts to convert
free cholesterol into cholesteryl esters?
a. Cholesterol esterase
b. Cholesterol oxidase
c. Lecithin-cholesterol acyltransferase
d. Lipase
c. Two enzymes are responsible for esterifying cholesterol, lecithin-cholesterol acyl transferase
(extracellular), and acetyl coenzyme A (acyl
CoA) cholesterol acyltransferase (intracellular).
Which of the following blood samples would serve
best to assay lipoproteins because this anticoagulant
acts to preserve lipoproteins?
a. EDTA plasma sample
b. Heparin plasma sample
c. Citrate plasma sample
d. Fluoride plasma sample
a. Althoughlipoproteins canbe assayed using avari
ety of anticoagulants, the preferred anticoagulant
is
ethylenediaminetetraacetic acid (EDTA)
because it preserves lipoproteins over time.
Exogenous triglycerides are transported in the
plasma in which of the following forms?
a. VLDL
b. Chylomicrons
c. LDL
d. Cholesteryl esters
b. Triglycerides are transported throughout the body by means of two lipoproteins: very-low-density lipoprotein (VLDL) and chylomicrons. VLDL carries endogenously derived triglycerides, and
chylomicrons
carry exogenously
derived triglycerides.
A patient presents to his physician for a lipid profile.
The following results are received:
HDL¼50 mg/dL
Total cholesterol¼300 mg/dL
Triglycerides¼200 mg/dL
The calculated LDL cholesterol is:
a. 200
b. 210
c. 290
d. 350
b. Low-density lipoprotein (LDL) cholesterol is calculated as follows:
LDL= TC-(HDL+TG/5)
LDL= 300-(50+200/5)
LDL=300-90
LDL=210 mg/dL
According to the National Cholesterol Education Program, which lipid or lipoprotein class is more important for therapeutic decision making (diet and medication decisions)?
a. Chylomicrons
b. LDL
c. HDL
d. Cholesterol
b. Low-density lipoprotein (LDL) is currently
the only lipoprotein or lipid that is recommended
for use by physicians for therapeutic lifestyle
changes.
Which of the following mechanisms accounts for
the elevated plasma level of b-lipoproteins seen in
hyperbetalipoproteinemia (Fredrickson’s type II
lipoproteinemia)?
a. Elevated insulin found in these patients
b. Apo B-100 receptor defect
c. Apo C-II–activated lipase deficiency
d. LCAT deficiency
b. Both forms of hyperbetalipoproteinemia (types IIA and IIB) are due to either a defect in the low-density lipoprotein (LDL) receptor (type
IIA) or a defect in Apo B-100 (type IIB).
Which enzyme is common to all enzymatic methods
for triglyceride measurement?
a. Glycerol phosphate oxidase
b. Glycerol phosphate dehydrogenase
c. Pyruvate kinase
d. Glycerol kinase
d. All enzymatic methods to measure triglycerides, regardless of the enzyme used, begin with the conversion of triglycerides to glycerol and fatty acids in the presence of the enzyme lipase, followed by the conversion of glycerol to glycerol-3 phosphate in the presence of the enzyme glycerol kinase.
A patient sample is assayed for fasting triglycerides
and a triglyceride value of 1036 mg/dL. This value
is of immediate concern because of its association
with which of the following conditions?
a. Coronary heart disease
b. Diabetes
c. Pancreatitis
d. Gout
c. Marked increases in triglyceride levels, between 1000 and 2000mg/dL have been associated with increased risk for the development of pancreatitis.
Which of the following apoproteins is inversely
related to risk for coronary heart disease and is a surrogate
marker for HDL?
a. Apo A-I
b. Apo B
c. Apo B100
d. APO E
a. ApoA-I is the predominant apoprotein associated with the high-density lipoprotein (HDL) molecule, activates (lecithin cholesterol acyltransferase[LCAT]), and is associated with reverse cholesterol transport. As a result, it is protective against coronary artery disease.
What is the most appropriate fasting procedure when a lipid study of triglycerides, total cholesterol, HDL,
and LDL tests are ordered?
a. 8 hours, nothing but water allowed
b. 10 hours, water, smoking, coffee, tea (no sugar or
cream) allowed
c. 12 hours, nothing but water allowed
d. 16 hours, water, smoking, coffee, tea (no sugar or
cream) allowed
c. The recommended fasting state for the study of lipids involves nothing but water for 12 hours before the blood sample collection.
Sucrose is considered a disaccharide that on hydrolysis yields which of the following sugars?
a. Glucose
b. Galactose and glucose
c. Maltose and glucose
d. Fructose and glucose
d. Sucrose upon hydrolysis yields fructose and
glucose.
John Smithers (21 years of age) is in to see his physician
for a pre-college physical and checkup. John
has always been extremely healthy. The following
laboratory results are received:
AStandard=0.679 AControl= 0.650
ASmithers= 0.729 CStandard= 200 mg/dL
Control range 190-195 mg/dL
John’s cholesterol concentration is approximately:
a. 186 mg/dL
b. 199 mg/dL
c. 209 mg/dL
d. 215 mg/dL
c. Using Beer’s law, the concentration of cholesterol in the patient (Smithers) serum is determined as follows: 0.679
Concentration(cholesterol)=Absorbance(unknown)/Absorbance(standard)x
Concentration(standard)
Concentration(cholesterol)= 0.729/0.679 x 200mg/dL
Concentration(cholesterol)= 209 mg/dL
200 mg=dL
Laboratory tests are performed for a postmenopausal,
57-year-old woman as part of an annual
physical examination. The patient’s random serum
glucose is 220 mg/dL, and the glycated hemoglobin
(HbA1c) is 11%. Based on this information, this
patient would mostly likely be classified as:
a. Normal
b. Impaired
c. Having type 1 diabetes
d. Having type 2 diabetes
d. According to the American Diabetes Association
criteria for the diagnosis of diabetes (below), this
patient would most likely be classified as having
type 2 diabetes.
Symptoms and a random plasma glucose
> or = 200 mg/dL or
Fasting plasma glucose > or =126 mg/dL or
2-hr OGTT > or = 200mg/dL or
Hbg A1c > or = 6.5%
Which of the biochemical processes below is promoted by insulin?
a. Glycogenolysis
b. Gluconeogenesis
c. Esterification of cholesterol
d. Uptake of glucose by the cells
d. Insulin lowers glucose levels by increasing the uptake of glucose into the cell and through
increased glucose metabolism.
