High School Biology : Understanding Differences with DNA

Study concepts, example questions & explanations for High School Biology

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Example Questions

Example Question #21 : Rna

DNA contains the following nitrogenous bases: adenine, guanine, thymine, and cytosine. RNA contains which of the following sets of nitrogenous bases?

Possible Answers:

Adenine, guanine, cystine, and thymine 

Adenosine, guanine, cystine, and uracil

Adenine, guanine, cytosine, and uracil

Adenine, guanine, cytosine, and uracil

Correct answer:

Adenine, guanine, cytosine, and uracil

Explanation:

Thymine is exclusively present in DNA. Uracil replaces thymine in RNA; thus, RNA contains the following four nitrogenous bases: adenine, guanine, cytosine, and uracil.

Example Question #12 : Rna Structure

Which of the following is not a component of RNA?

Possible Answers:

Ribose

Thymine

Cytosine

Adenine

Correct answer:

Thymine

Explanation:

RNA’s nucleotide components consist of a phosphate group, ribose, and nitrogenous bases. RNA’s nitrogenous bases include the purines adenine and guanine, and the pyrimidines cytosine and uracil. Thymine is a pyrimidine found exclusively in DNA. 

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