25 Questions
What is the naming convention for prokaryotic gene names?
First 3 letters describe function – 4th letter designates a specific gene.
How do prokaryotes primarily reproduce?
Simple binary fission producing genetically identical offspring.
What is the mechanism of genetic exchange involving a virus in prokaryotes?
Transduction
How do prokaryotes adapt and evolve despite not reproducing sexually?
They mutate and exchange genes.
Which type of mutation is shown using the delta symbol?
Deletion mutation
What do genomic loci encode in E. coli that are involved in maltose fermentation?
Genes
In classic bacterial genetics, how are mutations named?
By adding numbers to gene names
What type of mutations can result in DNA being added or lost, leading to frameshift mutations?
Insertion mutations
What is the process called when a prophage is induced and its DNA is excised from the genome & packaged into phage particles, sometimes including neighboring DNA by mistake?
Specialized transduction
What type of plasmid is typically involved in mediating conjugation, requiring cell-cell contact?
Conjugative plasmid
What is the name of the model plasmid originally identified in E. coli which is involved in conjugation?
F plasmid
What type of cells are strains with an F plasmid known as?
F+ cells
What do some tra genes encode that are produced by F+ cells and attach to F- cells only?
Conjugative pilus
What happens after the pilus attaches and brings two cells together during conjugative transfer of F plasmids?
Conjugative bridge forms
What does an Hfr cell stand for in the context of conjugative transfer?
High frequency recombination
What can be transferred to recipient strain's genome via Hfr cell conjugative transfer?
Part of donor’s chromosomal DNA
What will ultimately be lost if acquired DNA is not evolutionarily useful?
Much acquired DNA will ultimately be lost if not useful for evolution.
How can microbial genomes contain horizontally-acquired DNA?
Microbial genomes can contain horizontally-acquired DNA with different %GC content from rest of genome.
What are some impacts of horizontal gene transfer in microbiology?
Horizontal gene transfer has huge impacts on all aspects of microbiology, including infectious disease.
What is the natural mutation rate for prokaryotes per 1000 base pairs per round of replication?
10^-6 – 10^-7
Which enzyme is commonly used to identify colonies with altered gene expression in bacteria?
β-galactosidase
How can foreign DNA enter a prokaryotic cell?
Transformation, transduction, or conjugation
What plays an important role in the integration of foreign DNA into the host genome?
Genetic recombination, specifically homologous recombination
What are transposable elements?
Mobile genetic elements that can cause DNA rearrangements and insertions
How do many transposable elements move from one place to another?
Conservative (cut and paste) mechanisms
Study Notes
Bacterial Genetics and Gene Transfer
- Screening for mutants with a desired phenotype can be achieved by detecting single colonies that produce a detectable signal, such as color or fluorescence.
- The enzyme β-galactosidase is commonly used to identify colonies with altered gene expression in bacteria.
- The natural mutation rate for prokaryotes is approximately 10^-6 – 10^-7 per 1000 base pairs per round of replication.
- Acquiring mutations plays a major role in prokaryotic evolution, and horizontal gene transfer from foreign DNA plays an even bigger role.
- Foreign DNA can enter a prokaryotic cell through transformation, transduction, or conjugation, and once inside, it can be degraded, replicated as a separate entity, or integrated into the chromosome.
- Genetic recombination, specifically homologous recombination, plays an important role in the integration of foreign DNA into the host genome.
- Foreign DNA with homology to a region of the host chromosome can be inserted into the genome, replacing or duplicating native DNA sequences.
- Transposable elements, containing a transposase gene flanked by inverted repeats, are mobile genetic elements that can cause DNA rearrangements and insertions.
- Many transposable elements use conservative (cut and paste) mechanisms to move from one place to another, while others use a replicative mechanism to produce and insert a copy elsewhere.
- Transformation is the process by which free DNA is incorporated into a recipient cell, often through the capture of DNA by pili in competent organisms.
- Bacteriophages are viruses that infect bacteria and can operate through lytic or lysogenic pathways, integrating their DNA into the host DNA as a prophage.
- Transduction is a process in which a virus (phage) transfers DNA from one cell to another, contributing to gene transfer in bacteria.
Test your knowledge on bacterial genetics and gene transfer mechanisms, including mutation, horizontal gene transfer, genetic recombination, transposable elements, transformation, bacteriophages, and transduction. Explore how bacteria acquire genetic variation and exchange genetic material through different processes.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
