Question

dna and rna differ in all but one of the following ways. *
1 point
○ dna is double stranded while rna is single stranded
○ dna contains the base uracil while rna contains the base thymine instead
○ rna uses the sugar ribose in its backbone while dna uses deoxyribose

if an rna strand has 20 adenine, how many thymine would it have? *
1 point
○ 20
○ 40
○ none, because rna has uracil not thymine

dna is used to make _____ and rna is used to make _____. *
○ rna, proteins
○ rna, dna
○ proteins, dna

Explanation:

First Question (DNA and RNA differences)

To solve this, we analyze each option:

• Option 1: DNA is double - stranded, RNA is single - stranded (correct difference).
• Option 2: DNA has thymine, RNA has uracil (this option has the bases reversed, so it's the incorrect statement, which is what the question is asking for as the "BUT one" case).
• Option 3: RNA has ribose, DNA has deoxyribose (correct difference).

RNA is composed of the bases adenine, guanine, cytosine, and uracil. Thymine is a base found in DNA, not in RNA. So, regardless of the number of adenine in an RNA strand, there will be no thymine.

The central dogma of molecular biology states that DNA is transcribed to make RNA, and then RNA (specifically mRNA) is translated to make proteins.

Answer:

B. DNA contains the base uracil while RNA contains the base thymine instead

Second Question (RNA strand and thymine)