Question 1

The most abundant essential trace element in the body is ______, and the second most abundant is ______.&#10;A)iodine, selenium&#10;B)fluorine, copper&#10;C)iron, zinc&#10;D)chromium, manganese

Accepted Answer

Iron is the most abundant essential trace element in the body.Zinc is the second most abundant trace element.

Question 2

Which of the following cations is important in enzymes associated with nucleic acid and protein synthesis?&#10;A)aluminum&#10;B)zinc&#10;C)selenium&#10;D)molybdenum

Accepted Answer

Zinc is an important component of more than 200 metalloenzymes such as DNA and RNA polymerases which are associated with nucleic acid and protein synthesis.

Question 3

An aluminum measurement may be requested in which of the following situations?&#10;A)a patient receiving long-term total parenteral nutrition therapy&#10;B)a patient recovering from a liver transplant&#10;C)a patient developing frequent kidney stones&#10;D)a patient diagnosed with type 2 diabetes

Accepted Answer

A group of potentially vulnerable patients to aluminum toxicity are those receiving long-term total parenteral nutrition (TPN) therapy.Products used for TPN have been shown to contain appreciable aluminum contamination.Even with efforts to address this issue, there is evidence of significant variation of aluminum levels, even with different batches of the same main ingredient.

Question 4

A decreased plasma ceruloplasmin, increased level of copper in liver biopsy, and increased plasma nonceruloplasmin-bound copper are associated with which disease?&#10;A)Keshan disease&#10;B)Crohn's disease&#10;C)Wilson's disease&#10;D)Addison's disease

Accepted Answer

Wilson's disease is a genetic disease in which the liver has an impaired ability to excrete excess copper.This results in a buildup of copper in the liver, which would be detected by liver biopsy.Plasma ceruloplasmin, the combination of copper to its transport protein, is typically found decreased in Wilson's disease, along with an increase in nonceruloplasmin-bound copper.

Question 5

Which of the following elements is an important component of thyroid hormones?&#10;A)fluorine&#10;B)iodine&#10;C)manganese&#10;D)molybdenum

Accepted Answer

Iodine is an important constituent of thyroid hormones.Triiodothyronine (T₃) contains three iodine atoms per molecule, and thyroxine (T₄) contains four iodine atoms per molecule.Thyroid hormones are not physiologically active in the absence of iodine.

Question 6

Why are the essential trace elements fluorine and iodine not measured by atomic absorption spectrophotometry (AAS), as are all other essential trace elements?&#10;A)The concentration of fluorine and iodine are too high to be measured by AAS.&#10;B)The concentration of fluorine and iodine are too low to be measured by AAS.&#10;C)Fluorine and iodine cannot be differentiated by AAS, therefore measurement of either element is the sum of both elements.&#10;D)Fluorine and iodine are not metals and cannot be measured by AAS.

Accepted Answer

All essential trace elements are metals, with the exception of fluorine and iodine.AAS is a laboratory technique that can only measure metals.Since fluorine and iodine are halogens instead of metals, they will not be detected by AAS.Ion-selective electrode methodology is used to measure these two halogens.

Question 7

What is the laboratory method of choice in the analysis of essential trace metals?&#10;A)spectrophotometry&#10;B)fluorometry&#10;C)atomic absorption spectrophotometry&#10;D)nephelometry

Accepted Answer

Atomic absorption spectrophotometry has adequate sensitivity to measure essential trace elements.Essential trace metals that are present in higher levels may be measured by flame atomic absorption spectrophotometry, whereas metals present in lower concentrations are measured by the flameless electrothermal atomic absorption technique.Additionally, based on the theory of atomic absorption spectrophotometry, the presence of one metal can be measured in a mixture of metals.This degree of specificity coupled with adequate sensitivity makes atomic absorption spectrophotometry the method of choice in measuring essential trace metals.

Question 8

Which of the following essential trace elements exhibits antioxidant properties?&#10;A)chromium&#10;B)manganese&#10;C)molybdenum&#10;D)selenium

Accepted Answer

Selenium atoms are covalently bound to cysteine residues in the enzyme glutathione peroxidase.Glutathione peroxidase has strong antioxidant properties.Selenium and vitamin E are believed to act synergistically in this manner.

Question 9

Treatment of lead poisoning involves the use of a chelating agent.The effectiveness of this treatment is monitored in the laboratory by measuring lead levels in which of the following specimens?&#10;A)serum&#10;B)plasma&#10;C)red blood cell hemolysate&#10;D)urine

Accepted Answer

Treatment of lead poisoning with a chelating agent such as calcium ethylenediamine tetraacetic acid (Ca-EDTA) works by exchanging calcium for lead.Once the chelating agent circulates through the blood stream, it is removed from the circulation by the kidneys and excreted in the urine.Measurement of the amount of lead in the chelate found in the urine demonstrates the effectiveness of the treatment.

Question 10

Which of the following essential trace elements is important for the function of xanthine oxidase activity and for uric acid production?&#10;A)molybdenum&#10;B)manganese&#10;C)chromium&#10;D)selenium

Accepted Answer

Molybdenum is a cofactor of the enzyme xanthine oxidase, and this plays a role in the metabolism of purines to uric acid.

Question 11

Which of the following correctly compares the relative toxicity of the various forms of mercury (most toxic first and least toxic last)?&#10;A)elemental mercury, inorganic mercury, organic mercury&#10;B)organic mercury, inorganic mercury, elemental mercury&#10;C)inorganic mercury, organic mercury, elemental mercury&#10;D)inorganic mercury, elemental mercury, organic mercury

Accepted Answer

The answer of Which of the following correctly compares the...

Question 12

Which of the following describes the mechanism by which fluoride is believed to provide protection against dental caries?&#10;A)Fluoride neutralizes tooth-damaging acid by-products produced by bacteria.&#10;B)Fluoride anions substitute for hydroxyl anions in the hydroxyapatite crystal structure, causing the crystal structure to be harder.&#10;C)Fluoride serves as an activator of an enzyme which functions to replenish the hydroxyapatite crystal structure to keep teeth strong.&#10;D)Fluoride is a natural component of tooth enamel that is easily dissolved and must be replenished to provide protection against tooth decay.

Accepted Answer

The answer of Which of the following describes the mechanism...

Question 13

A deficiency of __________ may be associated with hyperglycemia, glucosuria, and glucose intolerance in a nondiabetic patient.&#10;A)chromium&#10;B)copper&#10;C)manganese&#10;D)molybdenum

Accepted Answer

The answer of A deficiency of __________ may be associated...

Question 14

The most common food source of mercury is:&#10;A)beef&#10;B)milk&#10;C)fish&#10;D)poultry

Accepted Answer

The answer of The most common food source of mercury...

Question 15

Hair would be an appropriate sample for the laboratory detection and measurement of which of the following toxic trace elements?&#10;A)aluminum&#10;B)arsenic&#10;C)cadmium&#10;D)lead

Accepted Answer

The answer of Hair would be an appropriate sample for...

Question 16

The following laboratory results are associated with which toxic trace element?
Delta-aminolevulinic acid - increased
Free erythrocyte protoporphyrin (zinc protoporphyrin) - increased
Anemia screen - positive

A)aluminum
B)arsenic
C)mercury
D)lead

Accepted Answer

The answer of The following laboratory results are associated with...

Question 17

Metallothionein binds copper, zinc and cadmium.Which of the following sequences relates the strength of the interaction between metallothionein and these metals? (answer format: the most firmly bound metal listed first and least firmly bound metal listed last)

A)cadmium, copper, zinc
B)zinc, cadmium, copper
C)copper, zinc, cadmium
D)None of the above; all metals bind equally.

Accepted Answer

The answer of Metallothionein binds copper, zinc and cadmium.Which of...

Question 18

Given that selenium may be found in all of the following areas, a sample from which area of the body should not be used for selenium measurement?&#10;A)plasma red blood cells&#10;B)plasma platelets&#10;C)nails&#10;D)hair

Accepted Answer

The answer of Given that selenium may be found in...

Deck 42: Trace Metals