Sat bio question

Test Preparation SAT Subject Test Preparation
1

<p>2) Radioactively labeled amino acids introduced into a growing cell culture would be incorporated by the cells. If the cells were involved in protein synthesis and secretion the labeled amino acids would appear in the following organelles in which order over a period of time</p>

<p>a) smooth ER-rough ER-golgi apparatus-nucleus</p>

<p>b)rough ER-smooth ER-golgi apparatus-plasma membrane</p>

<p>c)rough ER- golgi apparstus-smooth Er-plasma membrane</p>

<p>d)smooth ER-rough ER-golgi apparatus-plasma membrane</p>

<p>e) smooth ER-rough ER-golgi apparatus-lysosome</p>

<p>Isn't it B? The book says A.</p>

2

<p>Proteins are synthesized by ribosomes lining the Rough ER hence the name Rough ER. The Smooth ER is responsible for many things, but it only synthesizes fats and steroid hormones. A protein created by the Rough ER would travel through the Smooth ER into the Golgi Apparatus where it would be modified then shipped by vesicles to the plasma membrane. It would then leave the cell by exocytosis. So to answer your question B seems more like the right correct.</p>

3

<p>however it is also possible that it is not exocytosis but simply protien synthesis</p>