Nucleic Acids: The Molecules of Information
Nucleic acids are among the most remarkable biomacromolecules because they are both chemical structures and information carriers. Found in the acid insoluble fraction of every living tissue, they are polynucleotides — long chains built from a single repeating unit, the nucleotide.
This quiz follows Lesson 9: Nucleic Acids and tests the precise vocabulary that every later discussion of heredity and protein synthesis assumes. You will be asked about:
- Nucleic acids as polynucleotides and members of the true macromolecular fraction
- The three components of a nucleotide: a heterocyclic compound, a monosaccharide, and a phosphate
- Purines (adenine, guanine) versus pyrimidines (uracil, cytosine, thymine)
- Ribose as a pentose sugar and 2′ deoxyribose
- The definitions of DNA and RNA
Read each question carefully — the distinctions here are small but decisive. Good luck!
Q1. Nucleic acids are best described as which type of polymer?
Nucleic acids are polynucleotides: long chains built from a single repeating type of unit, the nucleotide.
Q2. Which three groups together comprise the true macromolecular fraction of any living tissue or cell?
The lesson states that nucleic acids, together with polysaccharides and polypeptides, comprise the true macromolecular fraction of any living tissue or cell.
Q3. In which fraction of a living tissue are nucleic acids found?
Nucleic acids are found in the acid insoluble fraction of any living tissue, along with polysaccharides and polypeptides.
Q4. A nucleotide has three chemically distinct components. Which set correctly lists them?
A nucleotide consists of a heterocyclic compound (the nitrogenous base), a monosaccharide, and a phosphoric acid or phosphate.
Q5. In a nucleotide, the nitrogenous base is chemically classified as which kind of compound?
The nitrogenous bases of nucleic acids are heterocyclic compounds, as stated in the lesson.
Q6. Which of the following is a substituted purine?
Adenine and guanine are substituted purines; cytosine, thymine and uracil are substituted pyrimidines.
Q7. Which pair correctly lists the substituted pyrimidines named in the lesson?
The lesson states that adenine and guanine are substituted purines while the rest — uracil, cytosine and thymine — are substituted pyrimidines.
Q8. The skeletal heterocyclic ring of adenine and guanine is called:
The skeletal heterocyclic ring is called purine, and adenine and guanine are its substituted forms.
Q9. Which sugar found in polynucleotides is described as a monosaccharide pentose?
The lesson describes ribose as a monosaccharide pentose; the other sugar found in polynucleotides is 2' deoxyribose.
Q10. A nucleic acid containing 2' deoxyribose is called:
A nucleic acid containing deoxyribose is called deoxyribonucleic acid (DNA), while one containing ribose is called ribonucleic acid (RNA).
Q11. Which nucleic acid contains ribose as its sugar?
A nucleic acid containing ribose is called ribonucleic acid (RNA); DNA contains 2' deoxyribose instead.
Q12. Which of the following nitrogenous bases is found in nucleic acids according to the lesson?
The heterocyclic compounds in nucleic acids are the nitrogenous bases adenine, guanine, uracil, cytosine and thymine. Adenosine, thymidine and cytidine are nucleosides, not bases.
Q13. Which statement about the sugar component of a nucleotide is correct?
The second component of a nucleotide is a monosaccharide — either ribose or 2' deoxyribose.
Q14. Which of the following is NOT one of the three components of a nucleotide?
A nucleotide has three components: a heterocyclic compound, a monosaccharide, and a phosphoric acid or phosphate. Amino acids are the building blocks of proteins, not nucleotides.
Q15. Which pair of bases are both substituted purines?
Adenine and guanine are substituted purines; cytosine, thymine and uracil are substituted pyrimidines.