DNA and RNA Nitrogen Bases Quiz
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Questions and Answers

What type of bond is formed between nucleotides in DNA?

  • Hydrogen bond
  • Phosphodiester bond (correct)
  • Ester bond
  • Covalent bond

    • In DNA, what type of bond links adenine with thymine?

  • Ionic bond
  • Three hydrogen bonds
  • Ester bond
  • Two hydrogen bonds (correct)

    • What is the primary structure of RNA?

  • Double helix
  • Alpha helix
  • Triple helix
  • Single strand of nucleotides (correct)

    • How many hydrogen bonds form between guanine and cytosine in DNA?

    <p>Three hydrogen bonds</p> Signup and view all the answers

    What is present at the 5’ end of a nucleic acid strand?

    <p>Free 5’-phosphate group</p> Signup and view all the answers

    How are nucleotides linked in a double helix structure of DNA?

    <p>Phosphodiester bonds</p> Signup and view all the answers

    What was the main conclusion drawn by Griffith from his experiment?

    <p>Dead S cells can transform living R bacteria into pathogenic S bacteria.</p> Signup and view all the answers

    Why are bacteria of the 'S' strain pathogenic according to the text?

    <p>They have a capsule that protects them from an animal's defense system.</p> Signup and view all the answers

    What does the term 'transformation' refer to in Griffith's experiment?

    <p>The change in genotype and phenotype due to the assimilation of external DNA by a cell.</p> Signup and view all the answers

    Why were some living cells of the nonpathogenic strain transformed into pathogenic cells in Griffith's experiment?

    <p>As a result of exposure to an unknown substance from dead pathogenic cells.</p> Signup and view all the answers

    What additional evidence supported DNA as the genetic material according to the text?

    <p>Studies of a virus infecting bacteria.</p> Signup and view all the answers

    What role did heat-killed cells play in Griffith's experiment?

    <p>They released an unknown substance that caused the transformation of living R cells.</p> Signup and view all the answers

    What did Watson and Crick conclude regarding the pairing of nitrogenous bases in DNA?

    <p>The pairing is dictated by the structure of the bases</p> Signup and view all the answers

    According to Franklin's model, how are the sugar-phosphate backbones arranged in DNA?

    <p>Antiparallel to each other</p> Signup and view all the answers

    How many hydrogen bonds are formed between adenine and thymine in a DNA base pair?

    <p>Two</p> Signup and view all the answers

    Which of the following nitrogenous bases is a pyrimidine present in DNA and RNA?

    <p>Cytosine</p> Signup and view all the answers

    In Franklin's space-filling model of DNA, how are the nitrogenous bases arranged?

    <p>Paired in the molecule's interior</p> Signup and view all the answers

    Which statement describes the pairing of cytosine and guanine in DNA?

    <p>They form three hydrogen bonds</p> Signup and view all the answers

    What is the complementary base sequence for the given DNA section: A-G-T-C-C-A-A-T-C?

    <p>T-C-A-G-G-T-T-A-G</p> Signup and view all the answers

    What is the main function of RNA in the genetic code?

    <p>Transmit information from DNA to make proteins</p> Signup and view all the answers

    Which type of RNA carries genetic information from DNA to the ribosomes?

    <p>Messenger RNA (mRNA)</p> Signup and view all the answers

    What is the role of transfer RNA (tRNA) in protein synthesis?

    <p>Carries amino acids to the ribosome</p> Signup and view all the answers

    What is the significance of the anticodon on transfer RNA (tRNA)?

    <p>It complements a specific codon on mRNA</p> Signup and view all the answers

    During DNA replication, what happens to the parent strands?

    <p>Each parent strand bonds with new complementary bases</p> Signup and view all the answers

    Which nitrogen base is unique to DNA but not found in RNA?

    <p>Thymine</p> Signup and view all the answers

    In which type of nucleic acid is uracil found as a nitrogen base?

    <p>RNA</p> Signup and view all the answers

    What type of sugar is found in DNA, distinguishing it from RNA?

    <p>Deoxyribose with no O atom on carbon 2'</p> Signup and view all the answers

    How are nucleosides named based on their nitrogen base?

    <p>By adding -osine for pyrimidines and -idine for purines</p> Signup and view all the answers

    What defines a nucleotide as compared to a nucleoside?

    <p>A nucleotide has a phosphate ester with the C5’ –OH group</p> Signup and view all the answers

    How do nucleotides form according to the text?

    <p>When the C5’ –OH on sugar bonds to phosphoric acid</p> Signup and view all the answers

    Study Notes

    DNA Structure and Bonds

    • Nucleotides in DNA are linked by phosphodiester bonds.
    • Adenine pairs with thymine through two hydrogen bonds.
    • Guanine forms three hydrogen bonds with cytosine in DNA.
    • At the 5’ end of a nucleic acid strand, a phosphate group is present.
    • In the double helix structure of DNA, nucleotides are linked by covalent bonds between the sugar of one nucleotide and the phosphate of the next.

    Griffith's Experiment

    • Griffith concluded that a 'transforming principle' could convert nonpathogenic bacteria into pathogenic ones.
    • Bacteria of the 'S' strain are pathogenic due to their ability to produce a protective capsule that prevents phagocytosis.
    • The term 'transformation' in Griffith's experiment refers to the process by which nonpathogenic bacterial cells acquired virulence from heat-killed pathogenic cells.
    • Some living cells of the nonpathogenic strain became pathogenic due to the uptake of genetic material from the heat-killed 'S' strain.

    Evidence for DNA as Genetic Material

    • Further supporting evidence for DNA as the genetic material came from the identification and experimentation of nucleic acids, establishing their role in heredity.
    • Heat-killed cells served as a source of genetic material that transformed nonpathogenic cells during the experiment.

    Base Pairing and DNA Structure

    • Watson and Crick concluded that nitrogenous bases pair specifically, with adenine always pairing with thymine and guanine pairing with cytosine.
    • According to Franklin's model, sugar-phosphate backbones in DNA run in opposite directions (antiparallel).
    • A DNA base pair of adenine and thymine is held together by two hydrogen bonds.

    Nitrogenous Bases

    • Cytosine and guanine pair through three hydrogen bonds.
    • Thymine is a pyrimidine nitrogenous base found only in DNA.
    • Uracil is a nitrogenous base found in RNA but not in DNA.
    • In DNA, deoxyribose sugar distinguishes it from ribose sugar in RNA.

    RNA Functions

    • RNA's primary function is to serve as a messenger carrying genetic information from DNA to the ribosomes.
    • Messenger RNA (mRNA) is responsible for carrying genetic information from DNA to ribosomes for protein synthesis.
    • Transfer RNA (tRNA) helps in protein synthesis by transporting specific amino acids to the ribosome.
    • The anticodon on tRNA is significant as it complements the mRNA codon, ensuring the correct amino acid is added during translation.

    Nucleotides and Nucleosides

    • Nucleosides are named based on their nitrogen base, with a prefix indicating the type (e.g., adenosine for adenine).
    • A nucleotide is defined as a nucleoside with an added phosphate group.
    • Nucleotides are formed when a phosphate group is attached to the sugar of a nucleoside.

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    Description

    Test your knowledge on the nitrogen bases found in DNA and RNA, including the differences between thymine and uracil. Explore the pentose sugars used in both DNA and RNA, as well as the distinction between ribose and deoxyribose.

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