Radioisotopes are frequently used to label molecules in a cell. The fate of atoms and molecules in a 18) ce'll can then be followed. Assume Saccharomyces cerevisiae is grown in a nutrient medium containing the radioisotope 3% After a 48-hour incubatir, the 35S would most likely be found in the S. cerevisiae's:.
A) nucleic acids.
B) proteins
C) carbohydrates
D) water
E) lipids

B) Proteins  

Explanation:

[³⁵S] is usually supplied as [³⁵S]methionine and [³⁵S]cysteine. These amino acids are incorporated into proteins.

A is wrong. Nucleic acids do not have sulfur in their molecules.  

C and E wrong. The carbohydrates and lipids in S. cerevisiae have no sulfur.

D is wrong. Water has only H and O in its molecules.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.