DNA & DNA Replication
In light repair
the covalent bonds between the thymine dimers are broken.
In a particular DNA molecule, 32% of the nucleotides contain the base A. What percent of the nucleotides in this DNA molecule contain the base C?
18%
Arrange the following proteins in the proper order in which they participate in DNA replication. 1 = Primase 2 = Helicase 3 = Single-strand binding proteins 4 = DNA polymerase III
2, 3, 1, 4
Which of the following DNA sequences is complementary to 5' TAGAC 3'?
5' GTCTA 3'
In the Meselson and Stahl experiment, Escherichia coli cells started the experiment with double stranded DNA, where each strand contained 15N (heavy) DNA (e.g. 15N15N). After TWO generations in the 14N medium, Escherichia coli cells contained
50% 15N14N DNA and 50% 14N14N DNA
According to Chargaff's rule, which of the following statements about double-stranded DNA is TRUE?
A = T and C = G and A + G = C + T
Which characteristic of DNA allows each strand of the molecule to act as a template that specifies the exact sequence of nucleotides in the other strand?
Complementarity of the bases
What enzyme is responsible for repairing thymine dimers using the energy of light?
DNA photolyase
Which protein has a helicase function?
UvrD
UV light damages DNA by causing
covalent bonds to form between thymine nucleotides next to each other on the same DNA strand.
How does UV light and other ionizing radiations damage DNA molecules?
creating thymine dimers between adjacent thymines in the DNA chain.
What kind of bond do thimine dimers weaken?
hydrogen bonds
