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Old 04-27-2010
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Molecular NE + G proteins = increased intracellular calcium

Norepinephrine stimulation of G proteins results in an increased intracellular concentration of calcium. This increase is not reversed by the extracellular calcium chelator EGTA. Which of the following is the most likely source of the increased intracellular calcium concentration?

(A) Endoplasmic reticulum
(B) Golgi complex
(C) Mitochondria
(D) Nucleus
(E) Plasma membrane
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Old 04-27-2010
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E - plasma membrane???
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Old 04-27-2010
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Default A.

Intracellular Ca2+ storages include mitochondria and the endoplasmic reticulum.
So A or C
Choice A. Calcium storage is one of the functions commonly attributed to the endoplasmic reticulum (ER) in non-muscle cells
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Old 04-27-2010
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Default hmm

If they say NE and they say increase in Calcium threw G protein isnt it an alpha 1 mechanism in smooth muscle?
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Old 04-28-2010
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Quote:
Originally Posted by just_md View Post
Intracellular Ca2+ storages include mitochondria and the endoplasmic reticulum.
So A or C
Choice A. Calcium storage is one of the functions commonly attributed to the endoplasmic reticulum (ER) in non-muscle cells
yes u're ryte the answer is A. but can u please elaborate yr reasoning further. i just dont see it.
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Old 04-29-2010
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Quote:
Originally Posted by Seetal View Post
yes u're ryte the answer is A. but can u please elaborate yr reasoning further. i just dont see it.
i think it s because norepinephrine(alpha-1 receptor) stimulates Phospholipase c which causes increase in IP3.Then u have rapid release of stored calcium ions from the ER to the cytosol
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Old 04-29-2010
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Quote:
Originally Posted by sam01 View Post
i think it s because norepinephrine(alpha-1 receptor) stimulates Phospholipase c which causes increase in IP3.Then u have rapid release of stored calcium ions from the ER to the cytosol
Yes ur right .
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Cell-Biology-, Molecular-Biology-, Step-1-Questions

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