Question 25 assays are based on the fact that a substrate a

Question 25

______________ assays are based on the fact that a substrate absorbs light of a particular wavelength.

Volumetric

Colorimetric

Radioisotope

Hydrometric

None of the above

1 points

Question 26

__________ chromatography separates protein molecules by size.

High performance liquid

Reverse phase

Gel filtration

Ion-exchange

Affinity

1 points

Question 27

Which of the following amino acids are basic?

arginine and leucine

lysine and tryptophan

tryptophan and leucine

lysine and arginine

none of the above

1 points

Question 28

Phenylalanine and __________ are nonpolar and have aromatic side chains.

serine

methionine

tryptophan

threonine

tyrosine

Solution

Answer:

25). B. Colorimetric

If a solute absorbs light at a particular wavelength, the absorbance is directly proportional to the concentration of the substance in solution. Ex: anti-proliferative assay, ATPase activity.

26). C.  Gel filtration

Gel filtration chromatography separates proteins that differ in size. A mixture of proteins is carefully layered on the top of a glass cylinder packed with porous beads. Smaller proteins travel through the column more slowly than larger proteins.

27). D. lysine and arginine

There are three amino acids that have basic side chains at neutral pH. These are arginine (Arg), lysine (Lys), and histidine (His).

28). C. tryptophan