toxicology question

[jnguyen]

hey guys!

i have a few questions regarding toxicology. sorry if this is the wrong place to post. MODs feel free to move this thread to the appropriate section if needed:

1) Which of the following would you expect to be an irreversible effect of xenobiotics?
a) damage to the liver, b) damage to the central nervous system, c) cancer d) birth defects, or e) all of the above except "A"

this question is mind boggling because i feel that the correct answer should be all of the above.

2) Perchlorate is an environmental industrial contaminant of ground water. persons who are exposed to it experience symptoms of hypothyroidism and develop enlargement of the thyroid gland. This is an example of:
a) dysregulation of gene expression, b) dysregulation of on-going cellular activity, c) dysregulation of electrically excitable cells d) dysregulation of internal cell maintenance or e) dysregulation of external cell maintenance.

so for this question i already eliminated a, b, and c. i`m creeping towards e because the external cell maintenance is being mutated but can i please have your opinions?

and finally,

3) Molecular repair often involves reducing oxidized molecules. Excessive oxidative damage can result in depletion of:
a) NAD, b) glutathione (GSH), c) NADPH, d) ATP, e) B, C and D can all be depleted

i honestly have no idea what the answer could be in this question.

thanks in advance for your feedback. these are all questions from my practice midterm which is tomorrow! hopefully all goes well. once again TIA!

[MrMistery]

No idea on the first two.
I will take a crack at number 3 though. If i had to pick one i would say glutathione, because it is used to neutralize reactive oxygen species by reducing them(the glutathione peroxidase reaction). However, the enzyme glutathione reductase needs NADPH in order to resynthesize reduced glutathione from the resulting oxidised glutathione.
Stupid question really...

[canalon]

I would give a crack at 1)
As far as I remember the liver can repair itself if the damages are not too extensive in percent of the organ or in time. All the other possibilities on the other hand do not appear to be reversible, so I would go for E

I have no idea for the rest

[jnguyen]

thanks for your input guys.

so for #1 i went over with my classmates and we decided on E because the liver can repair itself.

and for #3 i think we chose e also because we weren`t sure.

i think we were all stuck on #2. but thanks for replying guys! i really appreciate it. wish me luck =)