Question

You are trying to figure out what molecule, DNA, RNA, or protein, is responsible for making your bacterial cell lysate turn blue when you add a certain chemical. You divide your lysate into 4 tubes and add (a) Nothing, (b) protease, (c) RNase, and (d) DNase. Then you add your chemical of interest to each tube. Tubes (a), (b), and (d) turned blue but (c) remained colorless. You conclude:

a. The molecule responsible for making the blue color is DNA.
b. Your RNase didn't work.
c. The molecule responsible for making the blue color is RNA.
d. The molecule responsible for making the blue color is a protein.

Answer 1

c. The molecule responsible for making the blue color is RNA.

Step-by-step explanation:

Tube (a): DNA, RNA and proteins present ⇒ BLUE

Tube (b): DNA and RNA present ⇒ BLUE

Tube (c): DNA and proteins present ⇒ COLORLESS

Tube (d): RNA and proteins present ⇒ BLUE

RNA is the only molecule that is present every time the chamical is added and the tubes turn blue, and not present when the color doesn't change, meaning in tube (c) there's no reaction with the added chemical.

In conclusion, RNA is the only molecule reacting with the chemical and responsible for blue appearance.