Bacterial and Viral Genetics Flashcards
What are the 3 types of DNA transfer
Conjugation, Transduction and Transformation
In which cell (diploid or haploid) is it easier to observe mutations and why?
haploid are easy to identify due to loss-of-function mutations (usually gametes). They reproduce asexually through gene transfer
what is the process of conjugation?
transfer of DNA from one bacteria to another following direct cell-to-cell contact
what cells can act as donor cells
only strains of bacteria that contain the F factor can act as a donor cell.
what’s an F factor
it is a small circular piece of DNA, the ones containing the F factor is designated as F+
- F= cell to F- cell
What are sex pilus
they act as attachment sites for other bacteria
Made only by F+ strains
-helps create conjunction bridge
What is transduction?
the transfer of DNA between bacteria via a bacteriophage
what is a bacteriophage
they are viruses that specifically attack bacteria
What is the process of transformation?
it is when a bacterium takes up extracellular DNA in its environment
What are the two types of transformation?
natural transformation
artificial transformation
does natural transformation require help?
DNA uptake occurs without outside help and occurs in a wide variety of bacteria
what are competent cells?
they carry genes that encode proteins called competence factors that facilitate the binding, uptake and subsequent incorporation of the DNA into the bacterial chromosome
what enzyme cuts up the DNA in transformation in bacterial DNA
endonuclease enzymes
what are plasmids?
they are DNA that exist independently of the chromosomal DNA
what are the plasmids that can integrate into the chromosome?
episome
what are fertility plasmids?
they are F factors, allow conjugation
what factors give resistance to antibiotics?
resistance factors
what are degradative plasmids?
they allow the bacterium to metabolize an unusual substance
what are col plasmids?
they encode colicins, proteins that kill other Bacteria
what plasmid turns the bacterium into a pathogenic strain?
the virulence plasmids
what is the difference between haploid and diploid cells?
the number of complete sets of chromosomes
Haploid- 1 chromosome
Diploid- 2 chromosome
what is the difference between recessive and dominant mutations?
recessive mutations are both alleles being mutants
dominant mutations occur on only one mutant allele
What are the differences in viruses
host range differences
structural differences
genome differences
what are host range differences?
species a virus can infect
what are host range differences?
species a virus can infect
types of cells a virus infects
host cells
what are structural differences in viruses?
capsid (protein coat) size and shape
presence or absence of viral envelope
what are genome differences in viruses?
circular or linear, DNA or RNA, double or single stranded , size
lytic cycle
the lytic cycle involves the reproduction of viruses using a host cell to manufacture more viruses, bacteriophage burst out of cell
lysogenic cycle
involves the incorporation of the viral genome into the host cell genome, infecting it from within
