Molecular Biology MCQ Quiz With Answers

22 Questions | Attempts: 4006

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Molecular Biology MCQ Quiz With Answers - Quiz

Do you know all about DNA and RNA? Check out this molecular Biology MCQ quiz with answers and review your knowledge of DNA and RNA structure, replication, transcription & translation. Molecular biology is a branch of Biology that is concerned with studying chemical structures and biological phenomenon processes. It is mostly focused on nucleic acids (DNA and RNA) and proteins. This is an advanced-level test, so questions might be hard for you. Answer the questions carefully. Play the quiz now.


Questions and Answers
  • 1. 
    DNA nucleotides have three components. Which one of these is NOT part of a DNA nucleotide?
    • A. 

      Phosphate

    • B. 

      Deoxyribose sugar

    • C. 

      Ribose sugar

    • D. 

      A nitrogenous base

  • 2. 
    When considering DNA replication, the best way to describe it is:
    • A. 

      Semiconservative (half old, half new)

    • B. 

      Conservative (original remains, a new one is formed)

    • C. 

      Semipermeable (letting some molecules through)

    • D. 

      All of these

  • 3. 
    In DNA replication, the enzyme responsible for untwisting & 'unzipping' the DNA strands is....
    • A. 

      Helicase & gyrase

    • B. 

      Ligase

    • C. 

      DNA Polymerase III

    • D. 

      Primase

    • E. 

      RNAse H (DNA Polymerase I)

  • 4. 
    During DNA Replication, a short segment of RNA must form before DNA synthesis can begin. This is done by which enzyme?
    • A. 

      Helicase & gyrase

    • B. 

      DNA Polymerase III

    • C. 

      Ligase

    • D. 

      RNAse H (DNA Polymerase I)

    • E. 

      Primase

  • 5. 
    Small discontinuous fragments of DNA, called Okazaki Fragments, need to be joined together to form a complete strand. Which enzyme carries out this reaction?
    • A. 

      Helicase & gyrase

    • B. 

      DNA Polymerase III

    • C. 

      Ligase

    • D. 

      RNAse H (DNA Polymerase I)

    • E. 

      Primase

  • 6. 
    A new strand of DNA forms when nucleotides are linked together by phosphodiester bonds. The enzyme that enables this is...
    • A. 

      Helicase & gyrase

    • B. 

      DNA Polymerase III

    • C. 

      Ligase

    • D. 

      RNAse H (DNA Polymerase I)

    • E. 

      Primase

  • 7. 
    During DNA replication, there are two other proteins involved that aren't enzymes. These are the SSB's and the "sliding clamp" protein. What are their jobs?
    • A. 

      To speed up the copying of DNA & make sure it happens correctly

    • B. 

      To prevent annealing (closing) of 'unzipped' DNA + increase processivity

    • C. 

      To ensure that any errors in copying are excised before they become permanent

    • D. 

      To bring the correct nucleotides to their correct complementary partners

  • 8. 
    During DNA Transcription, only one strand is copied. This strand is the 3' -- 5' strand, and is called the _______________ strand.
    • A. 

      Leading

    • B. 

      Lagging

    • C. 

      Template

    • D. 

      Adenine

  • 9. 
    During DNA replication, one strand is copied in a nice, smooth, continuous manner. This strand is called the ______________ strand.
    • A. 

      Leading

    • B. 

      Lagging

    • C. 

      Template

    • D. 

      Adenine

  • 10. 
    During DNA replication, one strand is made discontinously, in short fragments, little by little. This is called the ____________________ strand.
    • A. 

      Leading

    • B. 

      Lagging

    • C. 

      Template

    • D. 

      Adenine

  • 11. 
    During transcription, a segment of DNA coding  AACGGATTATAT  would be transcribed to....
    • A. 

      TTGCCTAATATA

    • B. 

      AACGGATTATAT

    • C. 

      AACGGAUUAUAU

    • D. 

      UUGCCUAAUAUA

  • 12. 
    Although there are only 20 amino acids, there are 64 possible codons in the Genetic Code.  This is because of a property of the code called....
    • A. 

      Redundancy

    • B. 

      Repetitiveness

    • C. 

      Recombination

    • D. 

      Frequency

  • 13. 
    Because the mRNA codon, AUG, stands for an amino acid, it means that technically, every protein begins with which amino acid?
    • A. 

      Isoleucine

    • B. 

      Proline

    • C. 

      Methionine

    • D. 

      Tryptophan

  • 14. 
    A sequence of DNA codes: AAAAAAAAAAAAAAAAAAAAA After transcription and translation, it would yield which of the following?
    • A. 

      Nothing.... that's ridiculous!

    • B. 

      A polypeptide composed of 7 Lysines

    • C. 

      A polypeptide composed of 7 Phenylalanines

    • D. 

      A polypeptide composed of 6 Lysines

  • 15. 
    Where in the cell does transcription of DNA occur?
    • A. 

      The nucleus

    • B. 

      The cytoplasm

    • C. 

      Anywhere there is a ribosome

    • D. 

      All of these

  • 16. 
    Where in the cell does translation of mRNA happen?
    • A. 

      The nucleus

    • B. 

      The cytoplasm

    • C. 

      Anywhere there is a ribosome

    • D. 

      All of these

  • 17. 
    If an mRNA has a codon which is CGC, then the tRNA anticodon will be...
    • A. 

      CGC

    • B. 

      GCG

    • C. 

      UAU

    • D. 

      ATA

  • 18. 
    Which of the following is NOT true about the Ribosome?
    • A. 

      It is composed of two subunits, large & small

    • B. 

      It is a vital participant in both transcription & translation

    • C. 

      It has three sites (E, P, A) that accomodate tRNA's

    • D. 

      It is the cell's protein maker

  • 19. 
    A tRNA molecule picks up a Cysteine amino acid. The anticodon loop of this tRNA might have which of the following sequences?
    • A. 

      UGU, UGC

    • B. 

      ACA, ACG

    • C. 

      TGT, TGC

    • D. 

      All of these

  • 20. 
    The 'rough draft' version of an mRNA, the Primary Transcript, needs to be 'cleaned up' or edited before translation can occur. This editing involves....
    • A. 

      Removal of exons

    • B. 

      Removal of introns

    • C. 

      Complementary pairing

    • D. 

      Secondary pairing

  • 21. 
    If the DNA sequence of a gene is  TACCCATGTAAGGGC, then the final amino acid sequence produced from it, after transcription and translation, will be  
    • A. 

      TRP - PHE - LYS - ILE - LEU

    • B. 

      MET - GLY - SER - PHE - SER

    • C. 

      GLY - ASP - GLU - MET - MET

    • D. 

      None of the above

  • 22. 
    When cells transcribe & translate their DNA, the term we use for this is...
    • A. 

      Gene expression

    • B. 

      Genetic mutation

    • C. 

      General mayhem

    • D. 

      Genetic coding

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