Toxic effects of plants, fungi and algae

Question 1

All of the following statements regarding plant toxicity are true EXCEPT:

a. genetic variability plays a role in the toxicity of a plant
b. Plant toxins are most highly concentrated in the leaves
c. young plants may have a higher toxin concentration than older plants
d. The weather can influence the toxicity of plants
e. Soil composition can alter a plant’s production of toxin

Answer 1

b. Plant toxins are most highly concentrated in the leaves

Question 2

2. Hypericum perforatum (St John’s wort) poisoning of livestock results in which of the following?
   a. mitotic inhibition
   b. contact dermatitis
   c. inhibition of DNA synthesis
   d. photosensitivity
   e. hemorrhaging

Answer 2

d. photosensitivity

Question 3

Contact with which of the following plant species would be LEAST likely to cause an allergic dermatitis?

a. Urtica sp
b. philodendron sp
c. Rhus sp.
d. Dendranthema sp
e. Heva sp

Answer 3

a. Urtica sp

Question 4

Ingestion of a toxic plant causes vomiting and diarrhea via which of the following mechanisms?

a. relaxation of the lower esophageal sphincter
b. contraction of the muscular layer of the stomach
c. irritation of mucus membranes
d. interferences with chloride ion channels
e. interaction with an inhibitor G protein

Answer 4

c. irritation of mucus membranes

Question 5

Which of the following statements regarding lectin toxicity is false?

a. Lectins have an affinity for N-acetylglucosamine on mammalian neurons.
b. consumption of lectins can cause severe gastrointestinal disturbances
c. The fatality rate after ingestion of a fatal dose is very high
d. Some toxic lectins inhibit protein synthesis
e. A diet high in some lectins has been linked to reduced weight gain

Answer 5

c. The fatality rate after ingestion of a fatal dose is very high

Question 6

colchicine, found in lily bulbs

a. causes severe dehydration
b. is sometimes used as a purgative
c. causes a severe contact dermatitis
d. inhibits sphingolipid synthesis
e. blocks microtubule formation

Answer 6

e. blocks microtubule formation

Question 7

Activiation of a vannilloid receptor is characteristic of which of the following chemicals?

a. acetylandromedrol
b. capsaicin
c. colchicine
d. ergotamine
e. linamarin

Answer 7

b. capsaicin

Question 8

which of the following plant species is known to cause cardiac arrhythmias on ingestion?

a. Diffenbachia
b. phytolacca americana
c. Digitalis purpurea
d. Pteridium aquilinum
c. Cicuta maculate

Answer 8

c. Digitalis purpurea

Question 9

Dicumarol is a fungal metabolite that causes which of the following?

a. prothrombin deficiency
b. epileptiform seizures
c. acute renal failure
d. photosensitivity
e. parasympathetic overactivation

Answer 9

a. prothrombin deficiency

Question 10

Which of the following plant toxins does NOT affect the neuromuscular junction?

a. nicotine
b. anabasine
c. curare
d. anatoxin A
e. muscimol

Answer 10

e. muscimol