Wrong answer on #36 Biology Destroyer 2011?

[chance8]

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Consider the following: ATP-->cyclic AMP. The enzyme that catalyzes this reaction is called adenylyl cyclase. This enzyme is inactive until which hormone binds?

Answer: epinephrine

I agree but what about the other answer choices? Trypsin, glucagon FSH, LH.

FSH and LH, when they bind to receptors, also activates adenylyl cyclase.

Reference: http://www.medicine.virginia.edu/ba...ab/lecture_notes/lecture_notes/pdf/lh_fsh.pdf
http://www.reproduction-online.org/content/130/1/15/F1.expansion.html
Glucagon activates adenylyl cyclase

 

[MAdental]

I am pretty sure FSH and LH are lipid soluble, so they would enter the cell. I am 100% sure epinephrine and norepinephrine are water soluble, so they cant enter the cell...hence, they gota attach to something out of the cell. And we know that for cAMP to work, it needs to be activated by a foreign molecule since it has receptors on the ouside.........so the answer is epinephrine. hope it helps/makes sense

 

[chance8]

FSH & LH and glycoproteins and are water soluble. They attach to receptors on the cell.

Therefore, I believe the answer is: FSH, LH and epinephrine ...not just epinephrine alone.

I am pretty sure FSH and LH are lipid soluble, so they would enter the cell. I am 100% sure epinephrine and norepinephrine are water soluble, so they cant enter the cell...hence, they gota attach to something out of the cell. And we know that for cAMP to work, it needs to be activated by a foreign molecule since it has receptors on the ouside.........so the answer is epinephrine. hope it helps/makes sense

 

[Jab1113]

FSH & LH and glycoproteins and are water soluble. They attach to receptors on the cell.

Therefore, I believe the answer is: FSH, LH and epinephrine ...not just epinephrine alone.

Its peptide hormone vs. steroid hormones.

Steroid hormones are lipid soluble and examples include progesterone, estrogen, FSH, and LH just like MAdental was saying.

Peptide hormones are ones that are WATER soluble (also what MAdental said) and examples of those are norpinephrine nd epinephrine.

The answer they are looking for is one that is a SURFACE receptor which are the peptide hormones. In this case the only answer is epinephrine.

Hope that made sense

 

[AllahIsGreater]

Its peptide hormone vs. steroid hormones.

Steroid hormones are lipid soluble and examples include progesterone, estrogen, FSH, and LH just like MAdental was saying.

Peptide hormones are ones that are WATER soluble (also what MAdental said) and examples of those are norpinephrine nd epinephrine.

The answer they are looking for is one that is a SURFACE receptor which are the peptide hormones. In this case the only answer is epinephrine.

Hope that made sense

yep exactly, steroid hormones bind to nuclear receptors, while all the others bind to the cells surface

 

[Troyvdg]

yep exactly, steroid hormones bind to nuclear receptors, while all the others bind to the cells surface

FSH AND LH ARE PEPTIDE HORMONES (they bind to GPCRs), while they are glycoproteins, they cannot diffuse through the cell membrane-ONLY STEROID HORMONES can diffuse through the membrane and bind to a nuclear hormone receptor.Norepi binds to a beta andrenergic receptor, which is also a gpcr (seen in production of melatonin)

I'm fresh out of endocrinology. this question's answer is wrong.

 

[Jab1113]

FSH AND LH ARE PEPTIDE HORMONES (they bind to GPCRs), while they are glycoproteins, they cannot diffuse through the cell membrane-ONLY STEROID HORMONES can diffuse through the membrane and bind to a nuclear hormone receptor.Norepi binds to a beta andrenergic receptor, which is also a gpcr (seen in production of melatonin)

I'm fresh out of endocrinology. this question's answer is wrong.

I stand corrected. Good catch!

 

[kitejunky27]

yeh i agree its wrong, LH and FSH activate the cAMP signalling pathway

i am studying for endocrine right now

 

[Dotoday]

Other hormones like FSH and LH do not directly stimulate cAMP synthesis. They are however involved in a pathway. If the question asks which hormone directly stimulates cAMP synthesis, then epinephrine is the best choice among other choices.

 

[chance8]

Epinephrine actually acts in the same way as FSH & LH: it binds a receptor then activates adenylyl cyclase. See my links above 😀

Other hormones like FSH and LH do not directly stimulate cAMP synthesis. They are however involved in a pathway. If the question asks which hormone directly stimulates cAMP synthesis, then epinephrine is the best choice among other choices.