Studied by 0 people
Looks like no one added any tags here yet for you.
Barbara McClintock
A scientist who discovered transposons ('jumping genes') in corn and won the Nobel Prize in 1983.
Transposons
Segments of DNA that can move in and out of genes, disrupting their function.
Staphylococcus aureus
A gram-positive bacterium commonly referred to as Staph, known for causing skin and wound infections.
Methicillin-resistant Staphylococcus aureus (MRSA)
A strain of Staphylococcus aureus resistant to methicillin and other antibiotics.
Haploid
A single set of chromosomes, such as in bacteria, which allows for easier study of genetic mutations.
Mutation
A change in the nucleotide sequence of an organism's DNA.
Horizontal gene transfer
The transfer of genetic material between organisms that isn’t vertical transmission (e.g., from parent to offspring).
Auxotroph
A mutant organism that requires additional nutrients not required by the wild-type organism.
Prototroph
A microorganism that can synthesize all of its compounds from simple substances; does not require growth factors.
Spontaneous mutations
Mutations that occur naturally without human intervention.
Base substitution
A type of mutation that replaces one nucleotide with another.
Silent mutation
A mutation that does not change the amino acid sequence of the resulting protein.
Missense mutation
A mutation that results in a different amino acid being incorporated into a protein.
Nonsense mutation
A mutation that creates a stop codon, terminating protein synthesis prematurely.
Frameshift mutation
A mutation caused by insertions or deletions of nucleotides that change the reading frame of the genetic sequence.
Transposition
The process by which transposons move from one location in the genome to another.
Induced mutations
Mutations that result from external factors such as chemicals or radiation.
Chemical mutagens
Substances that cause mutations by altering DNA base sequences.
Base analogs
Compounds that resemble normal nucleobases and can be incorporated into DNA, leading to mutations.
Intercalating agents
Chemicals that insert themselves between base pairs in DNA, causing frameshift mutations.
Photoreactivation
A light-dependent repair mechanism that fixes thymine dimers formed by UV radiation.
SOS repair
A last-ditch DNA repair mechanism activated under extreme DNA damage.
Direct selection
A method used to isolate mutant cells that can grow on selective media, while their parent strains cannot.
Indirect selection
A method to isolate mutants by identifying auxotrophs from prototrophic parents through replica plating.
Ames test
A test to assess mutagenic potential of compounds by measuring reversion rates in bacteria.
Transformation
The process by which bacteria take up naked DNA from their environment.
Transduction
The transfer of bacterial genes from one bacterium to another via bacteriophages.
Conjugation
The direct transfer of DNA between two bacterial cells that are temporarily joined.
Hfr cells
Bacterial cells with an integrated F plasmid that can transfer chromosomal DNA.
Core genome
The set of genes common to all strains within a species.
Accessory genome
Genes present in some but not all strains of a species.
Mobile genetic elements
DNA sequences that can change positions within the genome, such as plasmids and transposons.
R (resistance) plasmids
Plasmids that confer resistance to harmful substances like antibiotics and heavy metals.
Ti plasmid
A plasmid from Agrobacterium tumefaciens that can be transferred to plants, causing tumors.
Prophage
Bacteriophage DNA that has integrated into the host bacterial genome.
Restriction enzymes
Proteins that cut DNA at specific sequences, protecting against invading DNA.
CRISPR system
An adaptive immune system in bacteria that provides resistance to foreign genetic elements.
spacer acquisition
The process in the CRISPR system where a fragment of invading DNA is integrated into the CRISPR array.
Bacterial defenses against invading DNA
Mechanisms such as restriction-modification systems and CRISPR that protect bacteria from foreign genetic elements.
Insertion sequence (IS)
The simplest type of transposon that encodes only the transposase enzyme.
Generalized transduction
A form of transduction where bacterial DNA is packaged into phage particles for transfer to other bacteria.
Genotype
The genetic constitution of an organism, describing the specific alleles it possesses.
Phenotype
The observable characteristics or traits of an organism, resulting from the interaction of its genotype with the environment.
Base-pair substitution
A mutation that replaces one nucleotide pair in DNA with another, potentially altering the resulting protein.
Spontaneous mutations
Mutations that occur without any external influence, often due to natural errors in DNA replication.
Induced mutations
Mutations that result from exposure to external agents, such as chemicals or radiation.
Chemical mutagens
Agents that cause mutations by interacting with DNA, such as alkylating agents, base analogs, and intercalating agents.
Photoreactivation
A DNA repair mechanism that uses light energy to directly reverse damage caused by UV radiation, specifically thymine dimers.
Excision repair
A DNA repair process that removes damaged bases and replaces them with the correct ones.
Direct selection
A method to isolate mutant organisms by using media that supports the growth of mutants while inhibiting wild-type strains.
Indirect selection
A method for isolating mutants by identifying non-requiring growth factors through techniques like replica plating.
Ames test
A screening method that assesses the mutagenic potential of compounds by measuring their ability to induce reversion mutations in specific bacteria.
Transposable elements
DNA sequences that can change positions within the genome and can cause mutations when they insert into or disrupt genes.
F plasmid
A specific type of plasmid that allows for bacterial conjugation and transfer of genetic material between cells.
Hfr cell
A bacterial cell possessing an integrated F plasmid that facilitates the transfer of chromosomal DNA during conjugation.
Mobile genetic elements (MGEs)
Genetic sequences that can move around within the genome, including transposons and plasmids, contributing to genetic diversity.
SOS response
A global response to DNA damage in bacteria activating several repair mechanisms when the DNA is severely damaged.
Gene expression
The process by which information from a gene is used to synthesize functional gene products like proteins.
Chromosomal mutation
A type of mutation involving a change in the structure or number of chromosomes, which can lead to genetic disorders.
Polyploidy
A condition in which an organism has extra sets of chromosomes, often observed in plants.
Recombinant DNA
DNA that has been artificially created by combining DNA from different sources.
Nucleotide
The basic building block of DNA and RNA, consisting of a base, a sugar, and a phosphate group.
Plasmid
A small, circular DNA molecule found in bacteria that is separate from chromosomal DNA and can replicate independently.
Gene therapy
A technique that modifies a gene to treat or prevent disease, often by adding a functional gene to replace a nonfunctional one.
Biotechnology
The use of living systems and organisms to develop or make products, often involving genetic modification.
Synthetic biology
An interdisciplinary branch of biology that involves the design and construction of new biological parts, devices, and systems.
Transcription
The process by which the genetic code from DNA is copied to mRNA for protein synthesis.
Translation
The process by which ribosomes synthesize proteins using the information carried by mRNA.
Genetic engineering
The direct manipulation of an organism's genes using biotechnology to alter its characteristics.
CRISPR-Cas9
A revolutionary genome editing technology that allows for precise and efficient modification of DNA.
Transgenic organism
An organism that has been genetically modified to contain genes from other species.
Modified nucleobase repair
Modified nucleobases can be repaired through excision repair mechanisms in which damaged bases are removed and replaced by correct ones.
Thymine dimer repair mechanisms
Cells repair thymine dimers primarily through photoreactivation, which uses light energy to directly reverse the damage, and nucleotide excision repair, which removes the damaged DNA segment.
Three general groups of chemical mutagens
Alkylating agents - add alkyl groups to nucleobases, causing mispairing;
Base analogs - mimic normal nucleobases, leading to incorrect base pairing;
Intercalating agents - insert between DNA base pairs, causing frameshift mutations.
DNA damage by X-rays and UV light
X-rays cause double-strand breaks and modify bases, while UV light primarily induces thymine dimers, resulting in improper base pairing during replication.
How do transposons contribute to genetic diversity in bacterial populations?
Transposons can move within the genome, causing mutations and rearranging genetic material, which can contribute to genetic diversity and adaptability.
What might be the consequences of a frameshift mutation in a gene?
A frameshift mutation can lead to a completely different amino acid sequence downstream, potentially resulting in a nonfunctional protein.
How does the Ames test determine the mutagenic potential of a compound?
The Ames test assesses the rate of reversion mutations in particular bacterial strains after exposure to the compound, indicating its potential to cause mutations.
Why are Hfr cells important in the study of bacterial genetics?
Hfr cells can transfer chromosomal DNA during conjugation, allowing researchers to study gene mapping and the transfer of genetic traits.
How do chemical mutagens differ from spontaneous mutations?
Chemical mutagens are induced by external agents causing changes in the DNA, while spontaneous mutations occur naturally due to errors in DNA replication.
What role does CRISPR-Cas9 play in genetic engineering?
CRISPR-Cas9 allows for precise editing of genetic sequences, enabling modifications to be made to DNA for research and therapeutic applications.
Explain how nucleotide excision repair functions in fixing DNA damage.
Nucleotide excision repair involves recognizing damaged DNA, removing the damaged section, and synthesizing new nucleotides to fill the gap, restoring the original sequence.
What are the implications of having an auxotroph in microbial genetics research?
Auxotrophs are valuable for studying metabolic pathways and gene function since they require additional nutrients not needed by prototrophs.
Describe the impact of horizontal gene transfer on antibiotic resistance in bacteria.
Horizontal gene transfer allows bacteria to acquire antibiotic resistance genes from other bacteria, leading to the rapid spread of resistance traits.
In what ways can the understanding of genomic mutations aid in developing gene therapies?
Understanding mutations can inform the development of targeted therapies that correct or compensate for genetic defects, improving treatment strategies.
