MCB3023 EXAM 2 QUESTIONS AND
ANSWERS (GRADED A)
Which of these would a signal peptide be used for in bacteria? - ANSWER-To move
a protein to the outside of the cell
Which of these is a point mutation that results in changing a codon from an amino
acid codon to a stop codon? - ANSWER-nonsense
Initiation of translation in bacteria starts with the binding of the ribosome to the
mRNA molecule. The ribosomal binding site is nearer the _________ end of the
mRNA molecule and is called the ________. - ANSWER-5' end; Shine-Dalgarno
sequence
The mRNA of bacterial cells is often polycistronic. What does this term mean? -
ANSWER-It contains the code for multiple peptides
After the translational process the polypeptide folds into the appropriate
conformation for proper functioning. What group of proteins aids in protein folding? -
ANSWER-chaperonins
Bacteriophages vary in their ability to infect different strains of bacteria. This is
because some bacteria contain _________ __________ that cut the phage DNA
after it enters the cell. - ANSWER-restriction endonucleases
Compared to the eukaryal genome, the bacterial genome: - ANSWER-contains
usually one chromosome and most genes occur in a single copy
Term for the transfer of donor DNA to a recipient bacterium via a bacteriophage -
ANSWER-transduction
Under what conditions will two different plasmids be incompatible? - ANSWER-If
they use similar methods of replication initiation (ori)
Escherichia coli strain K12 is considered a wild-type strain and does not have any
nutritional vitamin requirements. What term applies to this strain? - ANSWER-A
prototroph
What sized fragments will be generated by cutting DNA with a four base pair-
recognition restriction endonuclease if we assume equal A-T and C-G richness
within the DNA? - ANSWER-roughly 250 bp
The sequencing method which uses detection of pyrophosphate liberated when
nucleotides are added to a growing DNA chain is called: - ANSWER-Pyrosequencing
Which of these is TRUE regarding horizontal gene transfer? - ANSWER-It is always
occurring in nature
, Which of these is another term for the Sanger method of DNA sequencing? -
ANSWER-dideoxy sequencing
What are paralogs? - ANSWER-Genes that arise from a duplication event in an
organism
How do nucleotides connect to adjacent nucleotides in the Watson-Crick model of
DNA? - ANSWER-Via a covalent bond between the 3' hydroxyl of one nucleotide
and the 5' phosphate of the other.
What did the experiment by Avery, MacLeod, and McCarty in 1944 with the R and S
strains of Streptococcus pneumoniae demonstrate? - ANSWER-DNA was the
genetic material in cells.
What is the first protein to bind to the oriC region of the DNA molecule to start the
replication process? - ANSWER-DnaA
Which of these is a term for a point mutation that results in a change in the amino
acid specificity of the codon and the synthesized polypeptide? - ANSWER-missense
For the initiation of transcription in bacteria, RNA polymerase binds to what region on
the gene? - ANSWER-promoter
The DNA replication process in Archaea more closely resembles that in: - ANSWER-
Eukarya
What is the sigma factor of the RNA polymerase holoenzyme responsible for? -
ANSWER-recognition of the promoter region
A bacterium that can synthesize all organic molecules needed for its growth from
one carbon molecule, e.g. glucose, is known as a/an: - ANSWER-prototroph
Suppose a microbe has died and lysed, exposing its DNA to the environment. Some
of this DNA was taken up by another unrelated microbe and incorporated into its
genome. This is an example of which process? - ANSWER-horizontal gene transfer
Genetic elements that are able to "jump" around on the chromosome - ANSWER-
transposons
Which of these enzymes is not required for homologous recombination to occur? -
ANSWER-DNA polymerase
You are searching for a mutant strain of Salmonella enterica which is antibiotic
sensitive. Which method would you employ to find such a mutant? - ANSWER-
Replica plating
You mix Met+ Pro- Lys-, Met-, Pro- Lys+ and Met- Pro+ Lys- auxotrophic strains of
E. coli. After incubation time has passed, you place 1020cells per plate on agar to
detect potential prototrophic colonies. How many plates need to be screened if gene
ANSWERS (GRADED A)
Which of these would a signal peptide be used for in bacteria? - ANSWER-To move
a protein to the outside of the cell
Which of these is a point mutation that results in changing a codon from an amino
acid codon to a stop codon? - ANSWER-nonsense
Initiation of translation in bacteria starts with the binding of the ribosome to the
mRNA molecule. The ribosomal binding site is nearer the _________ end of the
mRNA molecule and is called the ________. - ANSWER-5' end; Shine-Dalgarno
sequence
The mRNA of bacterial cells is often polycistronic. What does this term mean? -
ANSWER-It contains the code for multiple peptides
After the translational process the polypeptide folds into the appropriate
conformation for proper functioning. What group of proteins aids in protein folding? -
ANSWER-chaperonins
Bacteriophages vary in their ability to infect different strains of bacteria. This is
because some bacteria contain _________ __________ that cut the phage DNA
after it enters the cell. - ANSWER-restriction endonucleases
Compared to the eukaryal genome, the bacterial genome: - ANSWER-contains
usually one chromosome and most genes occur in a single copy
Term for the transfer of donor DNA to a recipient bacterium via a bacteriophage -
ANSWER-transduction
Under what conditions will two different plasmids be incompatible? - ANSWER-If
they use similar methods of replication initiation (ori)
Escherichia coli strain K12 is considered a wild-type strain and does not have any
nutritional vitamin requirements. What term applies to this strain? - ANSWER-A
prototroph
What sized fragments will be generated by cutting DNA with a four base pair-
recognition restriction endonuclease if we assume equal A-T and C-G richness
within the DNA? - ANSWER-roughly 250 bp
The sequencing method which uses detection of pyrophosphate liberated when
nucleotides are added to a growing DNA chain is called: - ANSWER-Pyrosequencing
Which of these is TRUE regarding horizontal gene transfer? - ANSWER-It is always
occurring in nature
, Which of these is another term for the Sanger method of DNA sequencing? -
ANSWER-dideoxy sequencing
What are paralogs? - ANSWER-Genes that arise from a duplication event in an
organism
How do nucleotides connect to adjacent nucleotides in the Watson-Crick model of
DNA? - ANSWER-Via a covalent bond between the 3' hydroxyl of one nucleotide
and the 5' phosphate of the other.
What did the experiment by Avery, MacLeod, and McCarty in 1944 with the R and S
strains of Streptococcus pneumoniae demonstrate? - ANSWER-DNA was the
genetic material in cells.
What is the first protein to bind to the oriC region of the DNA molecule to start the
replication process? - ANSWER-DnaA
Which of these is a term for a point mutation that results in a change in the amino
acid specificity of the codon and the synthesized polypeptide? - ANSWER-missense
For the initiation of transcription in bacteria, RNA polymerase binds to what region on
the gene? - ANSWER-promoter
The DNA replication process in Archaea more closely resembles that in: - ANSWER-
Eukarya
What is the sigma factor of the RNA polymerase holoenzyme responsible for? -
ANSWER-recognition of the promoter region
A bacterium that can synthesize all organic molecules needed for its growth from
one carbon molecule, e.g. glucose, is known as a/an: - ANSWER-prototroph
Suppose a microbe has died and lysed, exposing its DNA to the environment. Some
of this DNA was taken up by another unrelated microbe and incorporated into its
genome. This is an example of which process? - ANSWER-horizontal gene transfer
Genetic elements that are able to "jump" around on the chromosome - ANSWER-
transposons
Which of these enzymes is not required for homologous recombination to occur? -
ANSWER-DNA polymerase
You are searching for a mutant strain of Salmonella enterica which is antibiotic
sensitive. Which method would you employ to find such a mutant? - ANSWER-
Replica plating
You mix Met+ Pro- Lys-, Met-, Pro- Lys+ and Met- Pro+ Lys- auxotrophic strains of
E. coli. After incubation time has passed, you place 1020cells per plate on agar to
detect potential prototrophic colonies. How many plates need to be screened if gene
