Toxic agents

Question 1

Metallothioneins:

Answer 1

Metallothioneins (MTs) are a family of small, highly conserved, cysteine-rich metal-binding proteins that are important for zinc and copper homeostasis, protection against oxidative stress, and buffering against toxic heavy metals
D: provide high-affinity binding of copper and mercury.

Question 2

Transferrin

Answer 2

Iron

Question 3

ceruloplasmin

Answer 3

Copper

Question 4

metallothioneins

Answer 4

Zinc

Question 5

albumin

Answer 5

nonspecific metal binding.

Question 6

LEAST likely to chelate metals?

Answer 6

-Cl

Question 7

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

Answer 7

inhibition of mitochondrial respiration.

Question 8

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

Answer 8

Ca2+

Question 9

Which of the following statements regarding mercury (Hg) toxicity is FALSE?

Answer 9

Mercury vapor inhalation is characterized by fatigue and bradycardia.

Question 10

Wilson disease

Answer 10

• Urinary excretion of copper is high.
• There is impaired biliary excretion of copper.
• The disease can be treated with liver transplantation.
• This is an autosomal recessive disorder

Question 11

Metals and medical therapy

Answer 11

• There are elevated levels of aluminum in the brains of Alzheimer’s patients.
• Lithium is used to treat depression.
• Chronic nephrotoxicity is a common result of excess aluminum exposure.
• Platinum salts can cause an allergic dermatitis.

Question 12

Humans consume food to provide energy needed to

Answer 12

drive cellular functions including digestion, metabolism, pumping blood, nerve activity, and muscle contractions

Question 13

Neural control of energy balance

Answer 13

may involve a balance between leptin’s action on orexigenic versus anorexigenic peptide expression.

Question 14

Excess calories may be…

Answer 14

stored as glycogen in the liver.

Question 15

Metabolic syndrome is a constellation of actions including…

Question 16

Excess caloric intake

Answer 16

may lead to nonalcoholic steatohepatitis.

Question 17

Although dieting may effectively reduce body weight,

Answer 17

toxicity may result from a loss of required nutrients.

Question 18

Body mass index

Answer 18

may be defined as body weight divided by height squared.

Question 19

Def. calories ++

Answer 19

• The set-point hypothesis proposes that food intake and energy expenditure are coordinately regulated by defined regions in the brain that signal to maintain a relatively constant level of energy reserve and body weight.
• Hormonal messages generated by the endocrine cells of the pancreas, adipose tissue, and GI tract are involved in orchestrating multiple responses associated with caloric intake and caloric utilization.
• Caloric content of foods generally assumes factors of 4, 9, and 4 for carbohydrate, fat, and protein.
• Liver, adipose, muscle, and other tissues adapt to excess caloric loads.

Question 20

Animal toxins

Answer 20

• The kidneys are responsible for the excretion of metabolized venom.
• Venoms can be absorbed by facilitated diffusion.
• Most venom fractions distribute unequally throughout the body.
• Venom receptor sites exhibit highly variable degrees of sensitivity

Question 21

Scorpion venoms do

Answer 21

• Affect potassium channels.
• affect sodium channels.
• affect chloride channels.
• affect initial depolarization of the action potential.

Question 22

widow spiders

Answer 22

Alpha-latrotoxin stimulates increased exocytosis from nerve terminals

Question 23

commonly caused by tick envenomation

Answer 23

• Rocky Mountain spotted fever.
• Lyme disease.
• Q fever.
• ehrlichiosis.

Question 24

characteristic Lepidoptera envenomation?

Answer 24

• increased prothrombin time.
• decreased fibrinogen levels.
• increased risk of hemorrhaging.
• decreased plasminogen levels.

Question 25

A species of which of the following animals produces a venom that contains 60% formic acid?

Answer 25

Ants

Question 26

Which animals has a venom containing histamine and mast cell-degranulating peptide that is known for causing hypersensitivity reactions?

Answer 26

Bees

Question 27

Which enzymes is not typically found in snake venoms?

Answer 27

histaminase

Question 28

Plant toxins

Answer 28

• genetic variability plays a role in the toxicity of a plant.
• young plants may have a higher toxin concentration than older plants.
• the weather can influence the toxicity of plants.
• soil composition can alter a plant’s production of toxin.

Question 29

Activation

Answer 29

Capsaicin