Sands Flashcards
What does the antiparallel nature of double-stranded DNA mean?
The two strands run from 5’ to 3’ in opposite directions.
While studying the structure of a small gene that was recently sequenced during the
Human Genome Project, an investigator notices that one strand of the DNA molecule
contains 20 A’s, 25 G’s, 30 C’s, and 22 T’s. How many of each base is found in the
complete double-stranded molecule?
A=42, G=55, C=55, T= 42
The extent of DNA synthesis in a cell could most specifically be determined by
measuring the incorporation of which of the following radiolabeled compounds?
Thymine
DNA contains which one of the following components?
Negatively charged phosphate groups on the exterior of the molecule
If a completely radioactive double-stranded DNA molecule undergoes two rounds of
replication in a solution free of radioactive label, what is the radioactivity status of the
resulting four double-stranded DNA molecules?
Half should contain no radioactivity
During which phase of the cell cycle is DNA replicated?
S
The sequence of part of a DNA strand is the following –ATTCGATTGCCCACGT-.
When this strand is used as a template for DNA synthesis, the product will be which one of
the following?
ACGTGGGCAATCGAAT
The isolation of nascent Okazaki fragments during DNA replication led to the surprising
discovery of uracil in the fragment. The uracil is present due to which of the following?
The need for a primer
Which of the following is true about the lagging strand?
It is synthesized as a series of Okazaki fragments.
What is a replication fork?
An area where the DNA separates into two strands and DNA synthesis occurs.
If a 1,000-kilobase fragment of DNA has 10 evenly spaced and symmetric replication origins and DNA polymerase moves at 1 kilobase per second, how many seconds will it take to produce two daughter molecules (ignore potential problems at the ends of this linear piece of DNA)? Assume that the 10 origins are evenly spaced from each other, but not from the ends of the chromosome.
D) 50
Which of the following enable all the DNA of a eukaryote to be replicated in 8 hours.
There are multiple origins of replication.
Which of the following is necessary for DNA polymerase to polymerize deoxynucleotides?
3’-hydroxyl group
Analysis of a cell line that rapidly transforms into a tumor cell line demonstrated an increased mutation rate within the cell. Further analysis indicated that there was a mutation in the DNA polymerase enzyme that synthesizes the leading strand. This inactivating mutation is likely to be in which of the following activities of this DNA polymerase?
3’-5’ exonuclease activity
Why is DNA synthesized only in a 5’ to 3’ direction?
It has to do with proof reading.
-and because the phosphate group is on the 5’end
DNA polymerase , the eukaryotic primase, differs from DNA polymerase by which of the following?
Does not contain 3’ to 5’ exonuclease activity
Which of the following enzymes are responsible for this chemical reaction? 5’-AACGGGATCCATTGCTA-3’ 5’-AACGGGATCCATTGCTA-3’ 3’-TTGCCCTAGGTAACGAT-5’ 3’-TTGCCCTAGGTAACGAT-5’
DNA polymerase
What is the polymerase that generates the primer in eukaryotes called
DNA polymerase α
-alpha
DNA polymerase δ - delta
Lagging
DNA polymerase ε
leading
DNA polymerase β
DNA repair
DNA polymerase α
primase in eukaryotes
Primase is not required during DNA repair processes because of which of the following?
DNA polymerase delta and epsilon can use any 3’-OH for elongation.
During DNA replication, which type of enzyme separates double-stranded DNA into the single-stranded DNA that is needed as a template for the DNA polymerases?
Helicase