L3: BACTERIAL GENETICS AND PATHOGENECITY Flashcards
study of genes, genetic variation, and heredity in organisms
Genetics
passing on of traits from parents to their
offspring; either through asexual reproduction or sexual reproduction
Heredity
Heredity (also called ____)
inheritance
the genetic information
Genotype
the observable traits
Phenotype
package of DNA with part or all of the genetic material of an organism
Chromosome
the molecule that carries genetic information for the development and functioning of an organism
DNA (Deoxyribonucleic acid)
the basic building block of the nucleic acids DNA and RNA.
Nucleotide
Nucleotide is made up of
Nitrogen BASE, sugar molecule, PO4 group
basic unit of HEREDITARY
Genes
sequence of nucleotides in DNA that is transcribed to produce a functional RNA
Genes
How do Human cells replicate and
multiply?
Metosis and Meiosis
How do bacteria replicate and multiply?
Binary Fission
haploid genome, single set of chromosomes, carry the genetic information needed for reproduction
Bacterial Chromosome
Single, circular double stranded DNA (ssDNA) carry the genetic information needed for reproduction
Bacterial Chromosome
extrachromosomal, self-replicating gene elements, non essential, smaller than bacterial chromosomes
Plasmids
Plasmids controls:
- Antibiotic R
- Production of Toxins
- Synthesis of bacterial virulence factors
also known as PHAGE
Bacteriophage
viruses that infect and replicate only in bacterial cells
Bacteriophage
consist principally of proteins plus nucleic acid (DNA or RNA, but not both), encode functions required for replication in bacteria
Bacteriophage
Bacteriophage enhance bacterial pathogenicity by;
- transferring genes encoding toxins
- duplicating the virulence factors
- changing the regulatory sequences controlling bacterial virulence genes
Exchange of Genetic Information (3)
Transformation
Transduction
Conjugation
Direct uptake, incorporation and expression of exogenous genetic material from its surrounding
TRANSFORMATION
Process of horizontal gene transfer by which some bacteria take up foreign genetic material from the
environment
TRANSFORMATION
The prerequisite for bacteria to undergo transformation is its ability to take up free, extracellular genetic material. Susch as bacteria are termed as “___”?
Competent cells
The process of gene transfer by transformation does not require a living donor cell but only requires the presence of persistent _____ in the environment
DNA
process by which a virus transfers genetic
material from one bacterium to another, BACTERIOPHAGE
TRANSDUCTION
the transfer of genetic material between bacterial cells by direct
cell-to-cell contact or by a bridge-like connection between two cells
CONJUGATION
CONJUGATION takes place through a
pilus
parasexual mode of reproduction in bacteria
CONJUGATION
change in the nucleotide sequence and can create new cellular functionalities or lead to the dysfunction of others
BACTERIAL MUTATION
occur spontaneously or by exposure to mutation-inducing agents, result from errors during DNA replication
BACTERIAL MUTATION
BACTERIAL MUTATION genetic outcomes
Silent mutation
Missense mutation
Nonsense mutation
The mutation changes the original codon into another codon that
codes for the same amino acid
Silent mutation
When a mutation in the sequence causes a codon to code for a
different amino acid
Missense mutation
A mutant stop codon replaces a wild-type codon, terminating translation resulting in a shortened protein.
Nonsense mutation
Physical Mutagens of Bacterial Mutation
UV, radiation
Chemical Mutagens of Bacterial Mutation
reactive oxygen species, alkylating
agents
Biological Mutagens of Bacterial Mutation
Transposons (bet species)
Defines the shape of the bacteria
Bacterial Cell Wall
Bacterial Cell Wall, Some components responsible for Pathogenicity:
M protein & Mycolic Acid
Bacterial Cell Wall, Main constituent:
PEPTIDOGLYCAN
Bacterial Cell Wall is part of the ____ reaction
Gram Stain
_____ cell wall consists of a thicker peptidoglycan on its outer part
gram positive cell wall
____ cell wall has lipopolysaccharides beyond its outer membrane and peptidoglycan on the middle
gram negative cell wall
fluid phospholipid bilayer that encloses the bacterial cytoplasm
Cytoplasmic Membrane
Selective permeable membrane, Site of energy production
Cytoplasmic membrane
Dormant, tough and non-reproductive structure produced by the bacteria
during unfavorable conditions
Endospores
Resting cell, resistant to high temperature, desiccant and chemical agents, Compose of Ca and Dipicolinic Acid
Endospores
Endospores are composed of
Calcium and Dipicolinic Acid
Increase in virulence by preventing PHAGOCYTOSIS
Capsule
Capsule Increase in virulence by preventing
PHAGOCYTOSIS
ANTIGENIC, Demonstrated by STAINING method (india ink), Forms colonies which are often slimy
Capsule
Capsule Demonstrated by STAINING method specifically ?
India Ink
Aka FIMBRIAE
Pili
proteinaceous, filamentous polymeric organelles expressed on the surface of
bacteria, SOMATIC 🡪 Attachment, Helps bacteria to adhere to host cell
Pili
Hair like appendage that protrudes from the surface of bacteria that is use for
locomotion, Locomotion 🡪 25C, non motile🡪 37C
Flagella
VIRULENCE FACTORS
- invade the host
- cause disease
- evade host defenses
Adherence Factors
- Pili
- Use to adhere to host cells
Antiphagocytic Factors
- Capsules
- M CHON
- Mycolic Acid
Enzymes
- Coagulase
- Fibrinolysin
- Hyaluronidase
- IgA1 Protease
Toxins
Endotoxin
Exotoxin