Genetic Exchange Among Concepts Flashcards
Prokaryotic Genome
- Bacteria have evolved the capacity to exchange ______ _______ among members of the same and different species
- ____-_________ elements (_____ not part of the chromosome) have the greatest capacity for the exchange of genetic information between bacteria due to their ______ nature
- genetic information
- Extra-chromosomal; genes; mobile
Characteristics of the Bacterial Chromosome
- Single _______ DNA molecule (500-5,000 kbp)
- ________ ________ DNA
- Linear array of ______ genes, _____ copy of each gene
- ________ of genes
- ______: Functionally related genes that exist naturally
- _______ _______: Virulence-related genes that encode for proteins that are virulence factors. Are ______ regions compared to operons and can be _______
- Circular
- Double stranded
- haploid; single
- Clustering
- Operons
- Pathogenicity Islands; larger; acquired
Genetic Map of the Chromosome
- Set gene ________ of the chromosome
- ____: Gene for the origin of replication
- ____: Gene for the termination of the replication of the entire chromosome
- order
- oriC
- ter
Chromosomal Replication
- Occurs in ____ directions in the bacterial chromosome
- ________ occurs in the 5’ –> 3’ direction
- _____ ____: Responsible for the easing the strain caused by supercoiling
- 2
- Synthesis
- DNA Gyrase
- _____/______ ____ ______: Process in which a microorganism incorporates genetic material from another microorganism without an offspring being produced
- Mechanism for attaining _________ plasticity in bacteria, and is an ________ for evolution
- Process discovered in _____ in 1959
- Suggested by _____ ____ that the genetic ______ of all modern organisms is derived through ____ ____ ______
- Horizontal/lateral Gene Transfer
- phenotypic; implication
- Japan
- Carl Woese; heritage; horizontal gene transfer
Consequences of Horizontal Gene Transfer
- Formation of _____ species results in _______
- Ability to ______ host defense mechanisms
- Acquire resistance to ________ agents
- new; evolution
- evade
- antimicrobial
Mobile Genetic Elements Types: 1. \_\_\_\_\_\_: Circular dsDNA that are much smaller than chromosomes and are never composed of \_\_\_\_\_. \_\_\_\_\_\_\_\_ \_\_\_\_\_\_: Mobile plasmids that can carry genes from one bacterial cell to another 2. \_\_\_\_\_\_\_\_ 3. \_\_\_\_\_\_\_\_
- Plasmids; Conjugative Plasmids
- Transposons
- Bacteriophages
-_______ are not integrated into the chromosome
- plasmids
Plasmids: General Properties
- ______ dsDNA
- ______ molecule
- Several to many _____, varies from plasmid to plasmid
- _________ copy number, helpful for cloning
- Bacteria will make additional ________ of the plasmid when ______ in order to spread them to the population
- Always
- Circular
- genes
- Characteristic
- copies; dividing
Plasmid Classification
- ____ _____/_ _____: Carry resistance against 1 or more antibiotics, multiple can exist in a bacterial cell, and was the ______ plasmid discovered
- ______ ______: Codes for small protein that is bactericidal for select species of bacteria, and ONLY effects _______
- ______/____ ______: Codes for proteins necessary for conjugation including genes for the __ pilus
- ______ ______: Codes for some bacterial toxins (______) or surface antigens such as capsules or pili. Effects _____/______ cells not ________
- ______ ______: Codes for enzymes involved in catabolism that allows bacteria to acquire the necessary proteins to metabolize sugars it normally wouldn’t
- _______ ________: Constructed plasmids used for transferring specific genes into the cell in a laboratory. Formed by taking pieces of ______ ______ plasmids and putting them together for the desired ______, and are used to make ______
- _____ ______: Encoded functions that have not yet been identified
- Drug Resistance/R Factors; first
- Bacteriocinogenic Factor; bacteria
- Fertility/Sex Factor; F
- Toxinogenic Factor; exotoxins; host/eukaryotic; bacteria
- Metabolic Factor
- Cloning Vector; naturally occurring; properties; drugs
- Cryptic Plasmid
Multiple Drug Resistance (MDR) Plasmid
- Discovered in 1959 in Japan by _____ _____ during a large epidemic of _____ caused by Shigella dysenteriae
- Contained genes for both ________ and drug ________
- Kiyoshi Shiga; dysentery
- conjugation; resistance
Bacteriocins Produced by Oral Bacteria
- ________: Plasmids used to kill other bacteria species that are closely related to each other. This is due to ________ for nutrients since they prefer to live in similar ______
- ______ _____: Used to test for the presence of bacteriocins by looking for _____ of _______ that are produced
- _______ _____: Contains the gene that has the bacteriocin that will kill the susceptible bacteria
- Bacteriocins form ________ channels in the membrane of other bacteria, causing _______ to flow out of the cell resulting in death
- _______: Found specifically in E. coli
- Bacteriocins; competition; environments
- Indicator Strain; zones of inhibition
- Producer Strain
- Calcium; calcium
- Colicins
Fertility/Sex Factor
- Genes regulate the______ of genetic information from 1 bacteria to another
- Donor strain directs the process of __________
- transfer
- conjugation
Transposons
-Most recently identified _____ ______, and found by American geneticist ____ ______ in maize
General Properties
-Always _______ like plasmids
-________ molecules, difference from _______
-Composed of ______ genetic regions
-Several to many genes in ______ region. Can have _________ repeats, carry genes for ______ and ______, and be of many ______.
-Undergo a lot of ________ making them difficult to _______
-Move by non-___________ recombination, allowing it to be inserted into many different _________
Unique Property:
-Can be inserted into other _______ ______ or into the _________ itself
- mobile element; Barbara McClintock
- dsDNA
- Linear; plasmids
- distinct
- core; inverted; virulence; resistance; sizes
- variability; classify
- non-homologous; sequences
- mobile elements; chromosome
Transposons: Transposition
-Very __________ and can move around easily
-___________ enzyme will cut in a specific position and the __________ will insert itself into that region
-Can be identified in region of _______ repeats that _______ their sequence
-_________ ______: Contain all the genes necessary for their own transfer
Result of Transposition:
-Creation of gene ______
-_______
-_______
-______ repeats will ______ the transposon
- promiscuous
- Restriction; transposon
- direct; sandwich
- Conjugative Transposons
- insertions
- Deletions
- Translocation
- Direct; sandwich
Bacteriophages
-Viruses that specifically attack _______
-Most are comprised of a _____ coat that has a geometric structure
-Some are _____
-_______ _____: Process that uses bacteriophages to control oral plaque ______
General Properties:
- Contain either ____ or ____, but never both
-____ can be double or single stranded, ____ is typically single stranded
-____ or _____ is always in a ______ coat
-Have a ____ host range
- bacteria
- protein
- filamentous
- Phage Theory; biofilms
- DNA; RNA
- DNA; RNA
- DNA; RNA; protein
- limited
Bacteriophages Structure
Head:
-_________: Contains proteins that will self assemble into a specific structure and contains the _____ _____
-_________: Protein subunits that make up the nucleocapsid
Tail:
-______ ______: Protein surrounding the core that may or may not be present
-_____ plate
-_____: Where the nucleic acid flows through
-____ ______: Give bacteriophages their specificity that recognize receptors on the surface. Can recognize _____, ______, and other surface Ag
- Nucleocapsid; nuclear material
- Capsomeres
- Contractile Sheath
- Core
- Tail Fibers; pili; fimbriae
Bacteriophage Classification
-Based on _____ and ____ ____ composition, aka _______ properties
Bradley’s Bacteriophage Groups
dsDNA:
-_____ __: Tails are contractible
-_____ __: Tails are long and non-contractible
-_____ __: Tails are short and non-contractible
ssDNA:
-_____ __: No tails and have large capsomeres
-_____ __: Filamentous
ssRNA:
-_____ __: No tails and small capsomeres
-structure; nucleic acid dsDNA; -Group A -Group B -Group C ssDNA: -Group D -Group F ssRNA: -Group E
Mechanisms of Genetic Exchange
- ________: Genetic alteration of a cell resulting from the direct uptake, incorporation, and expression of ________ genetic material. Requires _____ pieces of DNA that are ______, _____, and ___DNA. Must be _____ and _____ to bind to the several sites where the DNA binding proteins on bacteria are located, must be ______ so the ______-______ proteins can bind, must be ____ to bind, and the cells must be _______ to participate
- ________: Transfer of genetic material (_____) between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between 2 cells. Requires a _______ plasmid or ________ transposon, and this process can be used to map the bacterial __________
- _______: Process by which DNA is transferred from one bacterium to another by a bacteriophage
- Transformation; exogenous; long; naked; linear; dsDNA
- long; linear; naked; competence-specific; dsDNA; competent
- Conjugation; plasmids; conjugative; conjugative; chromosome
- Transduction
Transformation: F. W. Griffith Experiment
- Involved using ________ _______
- ______/__ ______: Contained a capsule making it virulent
- ______/__ ______: Lacked a capsule making it non-virulent
- Determined that there was a ______ ______ responsible for the ____ strain transforming the ___ strain into becoming virulent
- Bacteria must be ______ to replicate this process of transformation
- Streptococcus pneumoniae
- Smooth/S Strain
- Rough/R Strain
- transforming principle; S; R
- alive
Mechanism of Genetic Transformation in Gram-Positive Bacteria
Development of Competence:
-Competence ______ must be secreted for the bacteria to become competent to undergo _________. With very ______ populations the competence _____ can bind to other cells, making them _________ dependent
Steps:
1. Binding of ______ ______ with cell surface receptors
2. _______: Synthesis of _______-________ proteins
3. _________ exposes DNA-binding protein and _______ by chewing away at the ______ membrane
Transformation Process:
1. Fragment of ______ is bound to the cell surface at several sites where ____-______ protein are located
2. Bound DNA is nicked and cut by the _____, and the other strand is ________
3. Association of remaining DNA strand with ______-_____ proteins that coat the DNA, to eliminate the ______ charge. The ______ charge would be repelled by the ______ charge of the _____ membrane
4. Entry into the cell and replacement of one _______ DNA strand by the _____ DNA
-Can only take place while the bacterial cell is _________ so the uptaken DNA can be ______. The single strand only goes to a ____ bacterial cell, the _______ strand or the _____ strand, never both
Development of Competence
-factors; transformation; dense; factors; concentration
1. competence factors
2. Autolysin; competence-specific
3. Autolysin; nuclease; cell
Transformation Process:
1. dsDNA; DNA-binding
2. nuclease; degraded
3. competence-specific; negative; negative; negative; cell
4. endogenote; inserted; single; original; daughter
Conjugation
- Identified by __ _____ and __ _____ who won the 1958 Nobel Prize for Physiology in Medicine
- Occurs while both the ______ and _____ are replicating
- ___ ____: The donor cell that contains the F factor plasmid, this encodes for the ____ pilus. The tip of the _____ pilus is recognized by the __ ____. Will retain a copy of the _____ since it’s being replicated
- __ ____: Lacks the conjugative plasmid and is the recipient cell
- ______ _________ ______(__): Occurs when the F plasmid DNA becomes integrated into the chromosome of the ________ cells. The ________ cell becomes considered a ____ and is also now a donor cell. The ____ plasmid DNA is the last segment to be transferred. Very ____ process
- J. Lederbergy; E. Tatum
- chromosome; plasmid
- F+ Cell; sex; sex; F- Cell; plasmid
- F- Cell
- High Frequency Recombinant (Hfr); recipient; recipient; Hfr; F
Crossing an Hfr and a F- Cell:
-__ ____: Result of the cross where the plasmid has come out of the chromosome in the _______ cell, which now contains a piece of _________ DNA attached to the __ plasmid. This is how new genes are transferred in _________. Now considered a _____ cell
-F’ Cell; recipient; chromosomal; F; conjugation; donor
Conjugation: Application to Gene Mapping
- Used ____ strains to map bacterial chromosomes
- Stop the process via ______ after certain time intervals, and that the __ ____ was always last
- ___________ maps were depicted in the ____ it took to transfer the DNA, not the ______ of the chromosomal DNA
- First bacteria with its chromosome fully mapped was __ ____ _-___
- Hfr
- lysing; F plasmid
- Chromosomal; time; length; E. coli K-12
Quantifying Bacteriophages by Counting Plaques
-_______: Clear area on an agar plate
Steps:
1. Grow lawn of bacteria that are _______ to the bacteriophage
2. _______ of a bacteriophage suspension is added
3. Bacteria become _____ with the bacteriophage
4. Infected bacteria ___ releasing new ____ which infects neighboring cells
5. Infection and ____ continues to spread
-Each individual ______ came from an individual cell that ____due to infection by a ____
- Plaques
1. sensitive
2. Dilution
3. infected
4. lyse; phage
5. lysis - plaque; lysed; phage
Bacteriophage Multiplication: Bacteriophage 1-Step Growth Curve
- _____ ______: Initial period where nothing is happening in terms of growth. Bacteriophage _____ are being made by the cell
- _____ _____: No bacteriophage particles have been released. Phage particles have begun to be _______ inside the cell and the number of particles _________ inside the cell too
- _____ ____: Final number of bacteriophage particles produced. New phage particles have fully ______ causing the cells to ____ releasing newly formed phages
- Considered a __-____ process since the phage particles are only seen outside the cells until it’s almost all at once
- Eclipse Period; particles
- Latent Period; assembled; increases
- Burst Size; matured; lyse
- 1-step
Bacteriophage Assembly
- ____ Region
- _____ Region
- Long ___ ____
- ______ Phage gets released when the cell is lysed
- Head
- Tail
- Long tail fibers
- Competed
Transduction: 2 Types of Bacteriophages
- Identified by ________ and ______
- 2 types of phages:
1. ______ Phages
2. ______ Phages
- Lederberg; Zinder
1. Virulent
2. Temperate
_______ Cycle and the Virulent Phage
- _________ into the host cell
- _______ of DNA into the host
- _______ replication
- ________: New phage assembly
- Phage _______ leading to bacteria cell death
- ________ of new host cells
- End result is cell ______
- Lytic
1. Absorption
2. Injection
3. Phage
4. Maturation
5. release
6. Infection - death
_______ Cycle and Temperate Phages
- ________ to host cell
- ________ of DNA into host cells
- _________ integrates into the bacterial chromosome
- ________ replication occurs with the bacterial chromosome. _________ genes in the _____ chromosome prevent the ______ genome from being expressed. The bacteria is considered a ________ ________
- __________ Phages can be ______ to become virulent by some type of ______
- Lysogenic
1. Absorption
2. Injection
3. Prophage
4. Prophage; Suppressor; phage; phage; Lysogenic Bacterium
5. Temperate; induced; stimulus
-________ plasmids and transposons are how ________ resistance genes are passed on. ____________ transposons are more likely to occur and represent the most _________ process, since they’re very _________. This gives them the greatest potential impact on the future of clinical treatment of _______ disease
-Conjugative; antibiotic; Conjugative; frequent; promiscuous; infectious
