chapter 8,5,6 in Sun book, Exam 5

Monoclonal antibodies are derived from: (Objective 5)

A. different cell lines.

B. different clones.

C. a single cell line.

D. a heterogeneous mixture of clones

Answer: C. a single cell line.

Which of the following best describes haptens? (Objective 5)

A. Haptens are substances that are capable of binding an antibody but cannot by themselves stimulate an immune response.

B. Haptens are immunoglobulins capable of binding specifically to both natural and synthetic antigens.

C. Haptens can be any substance capable of reacting with an antibody but without necessarily being capable of inducing antibody formation.

D. Haptens are compounds that can be attached to antigens or antibodies and used as labels for immunoassays

Answer: A. Haptens are substances that are capable of binding an antibody but cannot by themselves stimulate an immune response.

A competitive immunoassay includes an antibody, patient antigen, and: (Objective 5)

A. a paramagnetic particle to which an antibody attaches.

B. an antibody to the antibody–antigen complex.

C. a label that is not attached to either an antibody or antigen.

D. an antigen with a label attached to its structure

Answer: D. an antigen with a label attached to its structure.

Acridinium ester and dioxetane are both examples of labels used in which of the following immunoassays? (Objective 2)

A. fluorescence polarization immunoassay

B. enzyme-multiplied immunoassay technique C. chemiluminescent immunoassay

D. substrate-labeled fluorescent immunoassay

 Answer: C. chemiluminescent immunoassay

Polyclonal gels, particles coated with iron oxide, and plastic beads are all examples of: (Objective 3)

A. a solid-phase material.

B. antigen labels.

C. immunogens.

D. double antibodies

Answer: A. a solid-phase material

Which of the following best describes a significant difference between homogeneous and heterogeneous immunoassays? (Objective 2)

A. There is a physical separation of bound from free fractions in a homogeneous immunoassay.

B. There is no physical separation of bound from free fractions in a homogeneous immunoassay.

C. A homogeneous immunoassay usually takes longer to perform because bound fractions must be physically separated from free fractions.

D. Separation of bound and free fractions is optional for either type of immunoassay.

Answer: B. There is no physical separation of bound from free fractions in a homogeneous immunoassay.

In fluorescence polarization immunoassay, the small fluorescein molecules chemically attached to the hapten react in which of the following manner? (Objective 6)

A. They don’t spin at all.

B. They spin 100 times faster than normal.

C. They spin more slowly in solution.

D. They spin freely in solution

 Answer: D. They spin freely in solution

Which of the following immunoassays uses a gold electrode to facilitate production of light? (Objective 4)

A. fluorescence polarization immunoassay

B. substrate-labeled fluorescent immunoassay

C. electrochemiluminescence immunoassay D. enzyme-multiplied immunoassay technique

Answer: C. electrochemiluminescence immunoassay

Luminescent oxygen-channeling immunoassay takes advantage of which of the following distance factors to initiate a chemiluminescent reaction? (Objective 4)

A. long diffusion distance of oxygen molecules in the first electronic state

B. short diffusion distance of oxygen molecules in the first electronic state

C. short absorption distances of oxygen

D. short diffusion distance of hydrogen molecules in the first electronic state

Answer: B. short diffusion distance of oxygen molecules in the first electronic state

The antibody that binds to hapten-enzyme in the EMIT assay: (Objective 6)

A. inhibits enzyme activity.

B. enhances enzyme activity.

C. facilitates the enzyme catalytic properties. D. has no effect on the reaction.

Answer: A. inhibits enzyme activity.

Chapter 6 is bottom

Which of the following is not a component of a nucleotide? (Objective 1)

A. 5′ carbon sugar

B. amino acid

C. nitrogenous base

D. phosphate group

Answer: B. amino acid

Which of the following is a step in the process of translation? (Objective 2)

A. RNA polymerase binds to the promoter sequence.

B. Introns are removed from the transcript.

C. A string of As are added to the 3′ end of the mRNA.

D. Anticodons on the tRNAs bind to their complementary codons on mRNA.

Answer: D. Anticodons on the tRNAs bind to their complementary codons on mRNA

How much DNA would be contained in 200 ml of a sample that has an A260 of 0.40 and an A280 of 0.20? (Objective 3)

A. 2 mg

B. 4 mg

C. 10 mg

D. 20 mg

Answer: B. 4 mg

(Note: An A260 of 1.0 corresponds to approximately 50 μg/mL of double-stranded DNA. So, 0.40 A260 50 μg/mL 200 mL = 4000 μg = 4 mg)

Which of the following is true about gel electrophoresis of DNA? (Objective 4)

A. DNA of smaller molecular weight will travel far from the point of application.

B. DNA migrates toward the cathode.

C. Increasing the voltage increases the resolution of DNA fragments separated in the gel.

D. DNA electrophoresis requires polyacrylamide as a matrix.

Answer: A. DNA of smaller molecular weight will travel far from the point of application.

(Note: DNA is negatively charged due to its phosphate backbone and migrates towards the anode (positive electrode). Higher voltage can sometimes decrease resolution due to increased heat. Agarose is more commonly used for larger DNA fragments, while polyacrylamide is used for smaller ones.)  

Restriction endonucleases function by: (Objective 5)

A. linking two pieces of DNA from different sources.

B. adding a phosphate group onto one end of the DNA.

C. cutting the DNA at specific nucleotide sequences.

D. breaking the DNA randomly to create fragments of manageable size.

Answer: C. cutting the DNA at specific nucleotide sequences.

Real-time qPCR differs from traditional PCR in that: (Objective 7)

A. primers are not necessary.

B. the amplicon is detected as the reaction progresses.

C. the amplicon is detected on a special fluorescent gel.

D. the reaction requires hybridization probes.

Answer: B. the amplicon is detected as the reaction progresses.

All of the following are clinical applications of FISH except for: (Objective 8)

A. detection of chromosome microdeletions. B. detection of oncogenes in tumor cells.

C. monitoring patients with sex-mismatched bone marrow transplants for engraftment.

D. detecting DNA from tumor-causing viruses in cytologic specimens.

Answer: D. detecting DNA from tumor-causing viruses in cytologic specimens.

(Note: FISH (Fluorescence In Situ Hybridization) primarily targets DNA sequences within chromosomes. While viral DNA can be detected using other methods like PCR, FISH is less commonly used for routine detection of viral DNA in cytologic specimens compared to its applications in cytogenetics and oncology.)

RNA differs from DNA in that RNA: (Objective 2)

A. contains thymine instead of uracil.

B. contains an H group instead of an OH group at its 2′ carbon.

C. is normally single-stranded.

D. is used to carry the genetic information of most viruses

Answer: C. is normally single-stranded.

Note: RNA contains uracil instead of thymine, has an OH group at the 2' carbon, and DNA carries the genetic information of most viruses.)

The protein product derived from the DNA sequence below contains which of the following amino acid sequences? (Objective 3) DNA: 3′ TACTTTCGCGGAACT 5′

A. tyrosine–phenylalanine–arginine–glycine–threonine

B. tyrosine–phenylalanine–arginine–glycine C. methionine–lysine–alanine–proline

D. methionine–lysine–alanine–proline–tryptophan

Answer: D. methionine–lysine–alanine–proline–tryptophan

(Note: First, transcribe the DNA sequence to mRNA: 5′ AUGAAAGCGCCUUGA 3′. Then, translate the mRNA sequence using the genetic code: AUG (Methionine), AAA (Lysine), GCG (Alanine), CCU (Proline), UGA (Stop). Therefore, the amino acid sequence is methionine–lysine–alanine–proline.)

Suppose a laboratory got 2 mg of DNA from a clinical sample, but the DNA isolation procedure stated that 10 mg was optimal. The laboratory’s result can be explained by all of the factors below except: (Objective 4)

A. a low patient white blood cell count.

B. inadequate harvesting of the buffy coat from the sample.

C. storage of the whole-blood sample at 22°C for 12 hr before use.

D. contamination of the sample with protein.

Answer: D. contamination of the sample with protein.

(Note: Low WBC count, inadequate buffy coat harvesting, and improper storage can all lead to lower DNA yield. Protein contamination would affect the purity of the DNA, not necessarily the total yield.)

Suppose a laboratory wanted to separate small DNA fragments that were 10 bps apart in size. The optimal technique to use for the separation is: (Objective 5)

A. agarose gel electrophoresis.

B. polyacrylamide gel electrophoresis.

C. pulse-field gel electrophoresis.

D. denaturing gel electrophoresis.

Answer: B. polyacrylamide gel electrophoresis.

(Note: Polyacrylamide gels have a smaller pore size and higher resolving power for separating small DNA fragments with small size differences compared to agarose gels. Pulse-field gel electrophoresis is used for very large DNA fragments, and denaturing gel electrophoresis is used to separate nucleic acids based on size in a denatured state, often for RNA or single-stranded DNA.)

More nonspecific binding of a probe to DNA sequences in a sample is encouraged when the: (Objective 7)

A. size of the probe is increased.

B. salt concentration is decreased.

C. temperature is decreased.

D. temperature is increased.

Answer: C. temperature is decreased.

(Note: Lower temperatures generally reduce the stringency of hybridization, allowing for more mismatched binding between the probe and the target DNA.)

Labeled antibodies are used as probes to detect proteins in the: (Objective 8)

A. hybrid capture assay.

B. Northern blot.

C. Southern blot.

D. Western blot.

Answer: D. Western blot.

(Note: Western blotting is a technique used to detect specific proteins in a sample using labeled antibodies.)

A suitable method to use for quantitation of HIV in patient blood is: (Objective 9)

A. bDNA.

B. DNA sequencing.

C. SDA.

D. Southern blot.

Answer: A. bDNA.

*(Note: bDNA (branched DNA) assays are signal amplification assays used for the direct quantitation of nucleic acids, such as viral RNA (HIV)

Chapter 8

Lipids are characterized by: (Objective 2)

A. insolubility in water and solubility in organic solvents.

B. solubility in water and organic solvents.

C. solubility in saline.

D. solubility in weak acids.

E. solubility in water and insolubility in organic solvents.

Answer: A. insolubility in water and solubility in organic solvents

Which is the most commonly found sterol in humans? (Objective 1)

A. cholesterol

B. cortisol

C. estriol

D. pregnanediol

Answer: A. cholesterol

The perhydrocyclopentanophenanthrene nucleus is found in: (Objective 1)

A. nucleic acids.

B. lecithin.

C. cephalin.

D. cholesterol.

E. triglycerides

Answer: D. cholesterol

Cholesterol functions in all of the following except: (Objective 1)

A. bile acid precursor.

B. steroid hormone precursor.

C. prostaglandin synthesis.

D. membrane structure.

Answer: C. prostaglandin synthesis.

Cholesterol esters are formed through the esterification of cholesterol with: (Objective 1) A. protein.

B. digitonin.

C. fatty acids.

D. Apo A-I

Answer: C. fatty acids.

Which of the following is false concerning blood cholesterol concentrations? (Objective 8)

A. Increased cholesterol is associated with diabetes mellitus.

B. Increased cholesterol is associated with hyperthyroidism.

C. Increased cholesterol is associated with nephrotic syndrome.

D. Cholesterol levels decrease following strenuous exercise.

E. Cholesterol levels are unchanged when comparing results from fasting and nonfasting blood.

Answer: B. Increased cholesterol is associated with hyperthyroidism. (

Note: Hypothyroidism is typically associated with increased cholesterol.)

Which enzyme is used in enzymatic cholesterol determinations to form hydrogen peroxide? (Objective 10)

A. lactate dehydrogenase

B. cholesterol oxidase

C. cholesterol kinase

D. cholesterol dehydrogenase

Answer: B. cholesterol oxidase

Which enzyme catalyzes the following reaction: glycerol + ATP → glycerol phosphate + ADP? (Objective 10)

A. glycerol phosphate dehydrogenase

B. glycerol kinase

C. hexokinase

D. pyruvate kinase

E. glycerol phosphate oxidase

Answer: B. glycerol kinase

The desirable range for cholesterol levels as determined by the NCEP is: (Objective 18)

A. less than 200 mg/dL.

B. 200–240 mg/dL.

C. more than 240 mg/dL.

D. more than 300 mg/dL.

Answer: A. less than 200 mg/dL.

Serum lipase catalyzes the: (Objective 13)

A. hydrolysis of triglycerides to fatty acids and glycerol.

B. hydrolysis of triglycerides to fatty acids and water.

C. synthesis of triglycerides from fatty acid and glycerol.

D. synthesis of cholesterol from fatty acids.

Answer: A. hydrolysis of triglycerides to fatty acids and glycerol.

The enzymatic determination of glycerol in triglyceride analysis usually involves conversion of glycerol to: (Objective 13)

A. phospholipid.

B. formaldehyde.

C. CO₂ and H₂O.

D. glycerol phosphate

Answer: D. glycerol phosphate.

Which of the following lipid results would be expected to be falsely elevated on a serum specimen from a non-fasting patient? (Objective 13)

A. triglycerides

B. cholesterol

C. HDL

D. LDL

Answer: A. triglycerides

A “milky” serum from blood collected about an hour after the patient has eaten a heavy meal often has elevated: (Objective 5)

A. chylomicrons.

B. globulin.

C. thymol turbidity.

D. calcium.

Answer: A. chylomicrons.

From 60% to 75% of the plasma cholesterol is transported by: (Objective 6)

A. chylomicrons.

B. very-low-density lipoproteins.

C. low-density lipoproteins.

D. high-density lipoproteins.

Answer: C. low-density lipoproteins.

Triglycerides are the main constituent of: (Objective 6)

A. chylomicrons.

B. VLDL.

C. LDL.

D. HDL.

E. A and B.

Answer: E. A and B.

A. chylomicrons.

B. VLDL

The lipoprotein that is responsible for the transport of cholesterol from peripheral cells to the liver for excretion is: (Objective 5)

A. HDL.

B. LDL.

C. VLDL.

D. ILDL.

Answer: A. HDL.

After a meal, the bloodstream transports chylomicrons and VLDL to all tissues of the body. The principal site of uptake is the: (Objective 5)

A. liver.

B. intestine.

C. kidney.

D. brain.

Answer: A. liver.

An increase of 10 mg/dL of HDL cholesterol would: (Objective 14)

A. increase the risk of myocardial infarction. B. decrease the risk of myocardial infarction. C. have no effect

Answer: B. decrease the risk of myocardial infarction.

Which apolipoprotein has the ability to increase the risk of coronary heart disease? (Objective 14)

A. Apo A-I

B. Apo B-100

C. Apo B-48

D. Apo E-11

Answer: B. Apo B-100

A 52-year-old man went to his doctor for a physical examination. The patient was overweight and had missed his last two appointments because of business dealings. His blood pressure was elevated, his cholesterol was 210 mg/dL, and his triglycerides were 150 mg/dL. The result of an HDL cholesterol test was 23 mg/dL (20–60 mg/dL). Which of the following would be this patient’s calculated LDL cholesterol value? (Objective 15)

A. 157 mg/dL

B. 137 mg/dL

C. 55.4 mg/dL

D. Cannot determine from the information given

Answer: A. 157 mg/dL (

Note: LDL cholesterol can be estimated using the Friedewald equation:

LDL Cholesterol =

Total Cholesterol - HDL Cholesterol - (Triglycerides / 5).

LDL = 210 - 23 - (150 / 5) = 210 - 23 - 30 = 157 mg/dL.)

The results of a lipid profile on a 40-year-old patient with a history of alcoholism would most probably be: (Objective 19)

A. elevated.

B. decreased.

C. normal.

D. Unable to determine from the information.

Answer: A. elevated.

(Note: Alcohol consumption can lead to increased triglyceride and cholesterol levels.)

To produce the most reliable results, a specimen for a lipid profile should be drawn: (Objective 10)

A. immediately after eating.

B. fasting, 10 to 14 hours after eating.

C. fasting, 4 to 5 hours after eating.

D. randomly, or any time without regard to the last meal.

Answer: B. fasting, 10 to 14 hours after eating.

Which of the following is a reagent commonly used to precipitate VLDL and LDL, thereby allowing the measurement of HDL-C? (Objective 14)

A. zinc sulfate

B. isopropanol

C. sulfosalicylic acid

D. dextran sulfate and MgCl₂

Answer: D. dextran sulfate and MgCl₂

Which lipoprotein has the least amount of protein? (Objective 6)

A. HDL

B. LDL

C. VLDL

D. Chylomicrons

Answer: D. Chylomicrons

side note: The lipoprotein with the most amount of protein is HDL (High-Density Lipoprotein), which has the highest protein-to-lipid ratio

Which of the following is a variant form of LDL associated with an increased risk of coronary heart disease? (Objective 2)

A. HDL ‘

B. Apo A-I

C. Lp(a)

D. VLDL

Answer: C. Lp(a)

The Friedewald formula for estimating LDL cholesterol should not be used when the: (Objective 2)

A. HDL cholesterol is greater than 40 mg/dL.

B. triglycerides are greater than 400 mg/dL.

C. plasma shows no visible evidence of lipidemia.

D. total cholesterol is elevated based on the age and sex of the patient.

Answer: B. triglycerides are greater than 400 mg/dL.