Transformation and homologous recombination allow for the formation of heteroduplex DNA. Which of the following would occur during DNA replication of this molecule?
A) One daughter strand is complementary to the recombinant DNA molecule, while the other daughter strand is complementary to the parent DNA molecule.
B) Both daughter strands are complementary to the recombinant DNA molecule.
C) Both daughter strands are complementary to the parent DNA molecule.
D) None of the answers are correct.
Hfr means high frequency of ________, and these cells are capable of transferring genes from their ________ to other cells.
A) transformation / chromosome
B) transduction / plasmids
C) recombination / chromosome
D) transduction / chromosome
Mutation rates are similar in Bacteria and Archaea, yet certain stressful conditions mutation rates increase. Why is the mutation rate not constant and close to zero all of the time?
A) Increased mutation rates can be advantageous in rapidly changing environments because some random mutations may be useful for survival.
B) Microorganisms carefully control the mutation rate of their DNA to match the environmental conditions and maximize evolution.
C) The increased mutation rate under stressful conditions is an indication that the microorganisms can no longer replicate their DNA properly and are about to die.
D) Constant mutation rates would halt evolution completely.
You work for a biotechnology company that uses Streptomyces strains to produce pharmaceutical products. A phage has infected and killed some of your Streptomyces strains during production, resulting in dramatically decreased yields.
To protect the strains from infection you propose to
A) introduce gene transfer agents into the Streptomyces cultures to transfer antibiotic resistance genes into your Streptomyces strains.
B) design and insert CRISPR spacer sequences into the genomes of your strains that are complementary to the genomes of the phages that are infecting the cultures.
C) infect the Streptomyces strains with a helper phage that will help the strains resist infection.
D) transform the Streptomyces strains with plasmids encoding antibody proteins that will protect them from phage infection.
Which of the following factors has delayed the development of laboratory-based genetic systems in Archaea?
A) There are no documented systems of conjugation in Archaea.
B) Homologous recombination does NOT occur in Archaea.
C) Archaea do NOT host viruses or plasmids.
D) Many archaea grow in extreme or unusual conditions that make the use of agar and traditional mutant screening techniques problematic.
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