Essential Idea: Genetic information in DNA can be accurately copied and can be translated to make the proteins needed by the cell.


Q1-3: These questions are about Meselon and Stahl’s DNA replication experiments.


1.  These experiments showed that DNA replication was ...

  • A. conservative
  • B. semi conservative
  • C. dispersive
  • D. Random
2. Meselon and Stahl grew E. Coli in a medium containing 15N  for several generations.  Which part of the DNA molecule contains 15N?
  • A. deoxyribose
  • B. phosphate
  • C. nucleotide
  • D. adenosine
3. After transferring the bacteria to 14N  they were grown and centrifuged and separated according to their density. After three generations what % of bacteria would contain only 14N ?
  • A. 100
  • B. 75
  • C. 25
  • D. 0
4. The first enzyme involve in DNA replication is helicase. This enzyme ...
  • A. unwinds the DNA
  • B. uses energy from ATP
  • C. breaks the bonds between complementary base pairs
  • D. all of the above
5. For a new strand of DNA to be made, which of the following is not required?
  • A. DNA polymerase
  • B. nucleotides
  • C. template strand of DNA
  • D. RNA polymerase
6. Why is Taq DNA polymerase used in PCR (Polymerase Chain Reaction)?
  • A. It is cheap
  • B. It is not denatured at 80oC
  • C. It is only found in bacteria
  • D. It does not affect the product of DNA replication

7. Which is the correct order for the process of transcription and the formation of mRNA?

I. RNA polymerase separates the DNA into two strands

II. RNA polymerase forms covalent bonds between the RNA nucleotides.

III. RNA nucleotides with complementary base pairing form along the antisense strand of DNA

IV. RNA polymerase binds to DNA at the site of a gene

  • A. I →  II → III → IV
  • B. II → I → IV → III
  • C. IV → I → III →  II
  • D. IV → II → III → I
8. How many codons are in this section of mRNA ACCUGGCAUAGC ?
  • A. One
  • B. Two
  • C. Three
  • D. Four
9. Which is the DNA base sequence for the strand of mRNA with the sequence UUAGGCAAU?
10. As more than one codon may code for an amino acid the code is known as
  • A. degenerate
  • B. universal
  • C. complicated
  • D. complementary
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