Toxic Effects of Metals

Question 1

Which of the following is not a major excretory pathway of metals?

a. sweat
b. urine
c. respiration
d. feces
e. hair

Answer 1

c. respiration

Question 2

Metallothioneins:

a. are responsible for metal transport in the bloodstream
b. are involved in the biotransformation of metals.
c. invoke hypersensitivity reactions
d. provide high-affinity binding of copper and mercury
e. are involved in extracellular transport of metals.

Answer 2

d. provide high-affinity binding of copper and mercury

Question 3

Which of the following metal-binding proteins is NOT correctly paired with the metal it binds?

a. transferrin–iron
b. ceruloplasmin– copper
c. metallothioneins– zinc
d. ferritan– lead
e. albumin– non-specific metal binding

Answer 3

d. ferritan– lead

Question 4

Which of the following groups is LEAST likely to chelate metals?

a. -COOH
b. -Cl
c. -NH
d. -OH
e. -SH

Answer 4

b. -Cl

Question 5

What is the mechanism of toxicity of arsenic (As)?

a. inhibition of mitochondrial respiration
b. impairment of calcium uptake by membrane transporters.
c. accumulation in renal corpuscle
d. abolition of sodium-potassium gradient
e. destruction of surfactant in the lungs

Answer 5

a. inhibition of mitochondrial respiration

Question 6

Lead’s toxicity is largely due to its ability to mimic and interfere with normal functioning of which of the following ions?

a. Na+
b. K+
c. Cl-
d. Fe2+
e. Ca2+

Answer 6

e. Ca2+

Question 7

Which of the following statements regarding mercury toxicity is FALSE?

a. a major source of environmental mercury is rainwater
b. Mercury vapor is much more dangerous than liquid mercury
c. Mercury vapor inhalation is characterized by fatigue and bradycardia
d. Microorganisms in bodies of water can convert mercury vapor to methylmercury
e. Methylmercury is the most important source of human mercury toxicity

Answer 7

c. Mercury vapor inhalation is characterized by fatigue and bradycardia

Question 8

Which of the following is a common symptom of nickel exposure?

a. renal failure
b. diarrhea
c. hepatic cirrhosis
d. contact dermatitis
e. tachycardia

Answer 8

d. contact dermatitis

Question 9

Which of the following statements regarding Wilson’s disease is false?

a. Serum ceruloplasmin is high
b. Urinary excretion of copper is high
c. There is impaired biliary excretion of copper
d. The disease can be treated with liver transplantation
e. This is an autosomal recessive disorder

Answer 9

a. Serum ceruloplasmin is high

Question 10

Which of the following statements regarding metals and medical therapy is false?

a. there are elevated levels of aluminum in the brains of Alzheimer’s patients
b. Lithium is used to treat depression.
c. Chronic nephrotoxicity is a common result of excess aluminum exposure
d. Platinum is used as a cancer treatment
e. Platinum salts can cause an allergic dermatitis.

Answer 10

c. Chronic nephrotoxicity is a common result of excess aluminum exposure