High School Biology : RNA Structure

Study concepts, example questions & explanations for High School Biology

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Example Questions

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Example Question #21 : Rna

Which of the following statements are true?

Possible Answers:

The 5-C sugar is exactly the same in both RNA and DNA.

RNA and DNA have no structural differences whatsoever.

DNA contains phosphates, while RNA does not.

RNA is double stranded, while DNA is single stranded.

RNA contains uracil, while DNA contains thymine.

Correct answer:

RNA contains uracil, while DNA contains thymine.

Explanation:

RNA is different than DNA in that it 1) is single stranded (DNA is double stranded), 2) contains uracil (DNA contains thymine instead), and 3) contains a ribose sugar (DNA contains a deoxyribose sugar). And since both DNA and RNA are made up of nucleotides, they will both contain phosphates.

Example Question #21 : Rna

Which of the following characteristics best describe RNA?  

I. It contains base pairs C, G, U, and A

II. It is double stranded

III. It stores hereditary information

IV. It is responsible for transcription of proteins

V. It is synthesized from DNA

Possible Answers:

I, II, and III

V only

I, IV, and V

III and IV

II, IV, and V

Correct answer:

I, IV, and V

Explanation:

RNA is composed of the sugar ribose and contains the nitrogenous bases C, G, U, and A.  RNA is single stranded and is essential for gene expression, transcription and translation of proteins.  RNA is synthesized by DNA; only DNA contains hereditary information.

Example Question #21 : Rna

Which DNA base is replaced by uracil in RNA? 

Possible Answers:

Thymine 

Cytosine 

Adenine 

Guanine 

Correct answer:

Thymine 

Explanation:

DNA is made up of Adenine, Thymine, Guanine, and Cytosine. RNA has these same bases, except in RNA, there is no Thymine. Instead, Uracil is found.  

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:

Adenosine, guanine, cystine, and uracil

Adenine, guanine, cytosine, and uracil

Adenine, guanine, cystine, and thymine 

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 #21 : Rna

Which of the following is not a component of RNA?

Possible Answers:

Ribose

Adenine

Cytosine

Thymine

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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