MBG QUESTIONS CHAPTER 9 questions
and answers
What are the 3 mechanisms that bacteria use to acquire new alleles (parasexual processes)? -
correct answer ✔✔Conjugation, transformation, transduction
What makes bacteria valuable research objects? - correct answer ✔✔Their small size (millions
can be present in a small test tube), rapid reproduction (they double every 30-40 mins),
selective media that can select for a specific kind of bacteria and identify the presence of an
active allele, their simple structures (no nuclei) and physiology, and their genetic variability
(since bacteria = monoploid and they have only one copy of every gene therefore aren't
recessive nor dominant).
What are some characteristics of bacterial viruses/bacteriophages? - correct answer ✔✔They
are not able to independently reproduce, they are somewhat parasitic. This means they require
some of their host's molecular machinery to replicate. They reproduce by infecting bacterial
cells.
Describe the process of bacteria growing in liquid or solid media. - correct answer ✔✔There is a
test tube containing sterile liquid media, which will contain the essential nutrients. This medium
will be inoculated with bacteria using an inoculating loop. The bacteria from the loop will start
growing in the media as the tube is incubated overnight at (37 degrees celsius) with some
shaking for aeration. The colour goes from golden/clear to opaque, representing the much
larger concentration of bacteria. Then to isolate a single species, pipette some liquid onto a
petri plate with some agar (solid) and spread. Little bumps will show up and each bump is the
result from the single bacterium from liquid falling down on a spot. Single bacterium can be
isolated and grow its own colony.
What does one colony represent? - correct answer ✔✔Genetically identical population since it
all comes from one single cell.
, What is a lawn? - correct answer ✔✔When the bacterial culture is so dense, it forms a uniform
coating
What do bacteriophages produce on plates with dense bacterial cultures within hours of
infection? - correct answer ✔✔Plaques or clearings. Each spot is where a single virus landed
and started infecting and killing cells.
How is the genetic material enveloped in a bacteriophage T4? - correct answer ✔✔There is a
protein coat that envelops the genetic material in the head.
How many base pairs and characterized genes are present in a bacteriophage T4? - correct
answer ✔✔The genome contains 168 000 base pairs and 150 characterized genes. This is fairly
large and complex.
What cycle does a bacteriophage T4 go through? - correct answer ✔✔Goes through a lytic
phase, meaning it lyses the cell to infect other cells. This means it injects the first cell, makes
dozens of copies of itself, then bursts out of that cell to infect hundreds of others. It simply
docks on the surface of the bacterial cell and injects its genetic material into bacteria.
How many base pairs and characterized genes are present in a bacteriophage λ? - correct
answer ✔✔Genome contains 48 502 base pairs and about 50 genes.
What cycle does a bacteriophage λ go through? - correct answer ✔✔May be lytic (lyses the cell
like T4) OR lysogenic (inserts its DNA into host cell genome and goes into latency)
What are retroviruses? - correct answer ✔✔Category of viruses that have RNA genomes.
What is the function of the enzyme called reverse transcriptase? - correct answer ✔✔Instead of
traditional transcription where you go from DNA to RNA, you take the RNA template and
reverse transcribe it into DNA, called cDNA. cDNA is complementary DNA to the RNA template.
Then the RNA strand can be degraded (because it is very fragile and prone to degradation) and
and answers
What are the 3 mechanisms that bacteria use to acquire new alleles (parasexual processes)? -
correct answer ✔✔Conjugation, transformation, transduction
What makes bacteria valuable research objects? - correct answer ✔✔Their small size (millions
can be present in a small test tube), rapid reproduction (they double every 30-40 mins),
selective media that can select for a specific kind of bacteria and identify the presence of an
active allele, their simple structures (no nuclei) and physiology, and their genetic variability
(since bacteria = monoploid and they have only one copy of every gene therefore aren't
recessive nor dominant).
What are some characteristics of bacterial viruses/bacteriophages? - correct answer ✔✔They
are not able to independently reproduce, they are somewhat parasitic. This means they require
some of their host's molecular machinery to replicate. They reproduce by infecting bacterial
cells.
Describe the process of bacteria growing in liquid or solid media. - correct answer ✔✔There is a
test tube containing sterile liquid media, which will contain the essential nutrients. This medium
will be inoculated with bacteria using an inoculating loop. The bacteria from the loop will start
growing in the media as the tube is incubated overnight at (37 degrees celsius) with some
shaking for aeration. The colour goes from golden/clear to opaque, representing the much
larger concentration of bacteria. Then to isolate a single species, pipette some liquid onto a
petri plate with some agar (solid) and spread. Little bumps will show up and each bump is the
result from the single bacterium from liquid falling down on a spot. Single bacterium can be
isolated and grow its own colony.
What does one colony represent? - correct answer ✔✔Genetically identical population since it
all comes from one single cell.
, What is a lawn? - correct answer ✔✔When the bacterial culture is so dense, it forms a uniform
coating
What do bacteriophages produce on plates with dense bacterial cultures within hours of
infection? - correct answer ✔✔Plaques or clearings. Each spot is where a single virus landed
and started infecting and killing cells.
How is the genetic material enveloped in a bacteriophage T4? - correct answer ✔✔There is a
protein coat that envelops the genetic material in the head.
How many base pairs and characterized genes are present in a bacteriophage T4? - correct
answer ✔✔The genome contains 168 000 base pairs and 150 characterized genes. This is fairly
large and complex.
What cycle does a bacteriophage T4 go through? - correct answer ✔✔Goes through a lytic
phase, meaning it lyses the cell to infect other cells. This means it injects the first cell, makes
dozens of copies of itself, then bursts out of that cell to infect hundreds of others. It simply
docks on the surface of the bacterial cell and injects its genetic material into bacteria.
How many base pairs and characterized genes are present in a bacteriophage λ? - correct
answer ✔✔Genome contains 48 502 base pairs and about 50 genes.
What cycle does a bacteriophage λ go through? - correct answer ✔✔May be lytic (lyses the cell
like T4) OR lysogenic (inserts its DNA into host cell genome and goes into latency)
What are retroviruses? - correct answer ✔✔Category of viruses that have RNA genomes.
What is the function of the enzyme called reverse transcriptase? - correct answer ✔✔Instead of
traditional transcription where you go from DNA to RNA, you take the RNA template and
reverse transcribe it into DNA, called cDNA. cDNA is complementary DNA to the RNA template.
Then the RNA strand can be degraded (because it is very fragile and prone to degradation) and
