1) A biologist wanted to replicate an entire strand of DNA in the laboratory. She added DNA plus the separate components needed for replication, but the DNA that was formed was defective. Each contained a normal strand of DNA paired with numerous segments of DNA that was a few hundred bases long. What had she probably left out of the mixture?
  1. DNA polymerase
  2. Nucleotides
  3. Ligase
  4. Primers

2) Will DNA polymerase be able to fill in the missing nucleotides using the top strand as a primer?
 

     AGGTCTGAC
5ā TCCAGACTGTTAGC 3ā

  1. Yes, because the new nucleotides will add to the 5ā end.
  2. Yes, because the new nucleotides will add to the 3ā end.
  3. No, because the new nucleotides canāt add to the 5ā end.
  4. No, because the new nucleotides canāt add to the 3ā end.

3) A human protein was inserted into the chromosome of bacteria in order to produce it in the laboratory. The bacteria then transcribed this gene into mRNA and then translated it into protein. The final protein was useless however because it was much longer than the natural human protein. What is the best explanation for this?

  1. Transcription begins at a different place in bacteria than in human cells.
  2. The human gene may contain introns that the bacteria canāt remove.
  3. The stop codons are different between prokaryotes and eukaryotes.
  4. The genetic code is different between prokaryotes and eukaryotes.
4) Which of the following is not true about a codon?
  1. It consists of three nucleotides
  2. It is the basic unit of the genetic code.
  3. It may code for the same amino acid as another codon.
  4. It may code for more than one amino acid.
5) If the operator in the lac operon is mutated so that the repressor can no longer bind, what effect will this have on transcription?
  1. None of the genes will be transcribed regardless of the presence of lactose
  2. Transcription will always be activated in the presence of lactose
  3. Transcription will always be activated in the absence of glucose.
  4. None of the above.