WGU Biochemistry Final Review
250 Q/A
- The polymerase chain reaction is a tool used to study protein structure.
True False - CORRECT ANSWER False Feedback PCR is a tool used to amplify a specific segment of DNA.What color is the primer in the following diagram?Red Purple Blue - CORRECT ANSWER Red Feedback Recall from the section on DNA replication that DNA polymerase needs a primer to begin DNA synthesis. This requirement means the primers will direct the DNA polymerase to only synthesize complementary strands of
the target DNA. (Note: In DNA replication, the primers are RNA primers,
while PCR generally uses DNA primers because they are more stable.) 1 / 4
dNTPs are DNA nucleotides used in PCR.True False - CORRECT ANSWER True Feedback dNTPs stands for deoxynucleotide triphosphates, which are the nucleotides used in DNA synthesis.A thermocycler is a machine used for PCR that varies the temperature of a sample.True False - CORRECT ANSWER True Feedback For PCR, in each cycle, the two strands of the duplex DNA are separated by heating, then the reaction mixture is cooled to allow the primers to anneal (or pair) to their complementary segments on the DNA. Next, the DNA polymerase directs the synthesis of the complementary strands. The use of a heat-stable DNA polymerase eliminates the need to add fresh enzyme after each round of heating (heat inactivates most enzymes).Hence, in the presence of sufficient quantities of primers and dNTPs, PCR is carried out simply by cycling through the different temperatures for strand separation, primer annealing, and DNA synthesis.The thermocycler is the machine that is used to vary the temperature of the samples. 2 / 4
DNA polymerase is used in DNA replication and in PCR.True False - CORRECT ANSWER True Feedback Both PCR and DNA replication require DNA polymerase to make new copies of DNA.Which of the following changes can NOT be detected using PCR?Differences in DNA sequence Epigenetic changes Deletions Insertions - CORRECT ANSWER Epigenetic changes Feedback Epigenetic changes do not affect the sequence of the DNA. PCR is used to look at the DNA sequence.Which of the following components is NOT used in PCR?DNA template DNA nucleotides RNA polymerase Primers - CORRECT ANSWER RNA polymerase Feedback PCR makes a DNA copy, so DNA polymerase is used. 3 / 4
Assuming there is one copy of the target DNA sequence before PCR, how many copies of DNA are there after 5 PCR cycles?256 6
65,536
16
32 - CORRECT ANSWER 32
Feedback Each cycles double the numbers of DNA copy. Round 1: 1->2. Round 2: 2 - >4. Round 3: 4 -> 8. Round 4: 8 ->16. Round 5: 16 ->32.DNA polymerase can synthesize new DNA strands in which direction?3' to 5' 5' to 3' any direction N-terminus to C-terminus - CORRECT ANSWER 5' to 3' Feedback DNA needs a free 3' end to bind to and initiate synthesis of a DNA. It synthesizes in a 5' to 3' direction.The following are steps involved in a polymerase chain reaction. Which is
the correct order:
Elongation, denaturation, and annealing Denaturation, annealing, and elongation
- / 4