Physiology, Metabolism & Genetics Flashcards
3 Major/ Basic Nutritional needs of bacteria:
C, N, E
Carbon
Nitrogen
Energy (ATP)
Can grow simply, using CO2 as sole source of carbon
Autotrophs
Require complex organic sources such as glucose, carbohydrates, proteins or lipids
Heterotrophs
Medically significant & associated with infection
Requires additional nutrients such as vitamins, hemoglobin, etc.
Fastidious
Environmental Factors Influencing Bacterial Growth:
P, T, G
pH
Temperature
Gaseous Composition
Pathogenic bacteria grow best at what pH?
Neutral pH (7.0-7.5) Culture media are adjusted to this pH
Psychrophiles
Cold-Loving (10-20 degC)
Mesophiles
Moderate Temperature (20-40 degC)
Majority associated with disease
Thermophiles
High Temp (50-60 degC)
Agents of Intoxication & not really infections
Human Pathogens grow at __ degC
37 degC
Cannot grow in absence of oxygen
Obligate aerobes
Require reduced level of oxygen (5-6% O2)
microaerophilic
Can grow with or without oxygen
facultative anaerobes
Cannot grow in presence of oxygen
Obligate anaerobes
Can survive but cannot grow in aerobic conditions
aerotolerant anaerobes
Requires increased CO2 (best at 5-10% CO2)
Capnophilic
Bacteria Replicate by?
Binary Fission
What is Binary Fission?
Binary Fission is when one cell asexually divides into two cells
What is Binary Fission?
Binary Fission is when one cell asexually divides into two cells
Time required for 1 cell to divide into two cells
Generation Time/ Doubling Time
Bacterial Growth Curve Phases:
Lag Phase
Log Phase
Stationary Phase
Decline Phase/ Death Phase
Phase where bacteria prepares to divide; little to no cell division
Lag Phase
What happens in the Log phase?
Cells actively replicate; maximum rate of doubling
Sensitive to adverse conditions and antimicrobial drugs
Exhaustion of nutrients & accumulation of waste products; bacterial count remains constant
Slow growth rate
Stationary Phase
Number of nonviable cells exceed number of viable cells
Death/ decline phase
Doubling time is short, ____ replication rate
Doubling time is ____, slow replication rate
higher; longer
Bacteria can be differentiated through:
S, EP, pH
Utilization of Substrate
Specific End-Product
production of alkaline or acidic pH
genotype
genetic potential
phenotype
physiologic manifestation
single, closed, circular piece of supercoiled ds-DNA
Bacterial genome
small circular pieces of DNA in cytoplasm that contain extra genetic information
Plasmid.
can code for genetic resistance or endotoxins
can be replicated & passed to daughter cells
“Jumping Genes”
Transposons
Insertion Sequences
Small mobile nucleic acid strands capable of activating or inactivating genes; may be independent or part of transposon
FACT: Transposons can have insertion sequences at the end
What is Mutation?
Changes that occur in DNA code
Mutation that changes one nucleotide base leading to a change in single amino acid within a protein
Point Mutation/ Base Mutation
One or a few nucleotide pairs are deleted or inserted in the DNA
Frameshift Mutation
Gene transfer or gene exchange between homologous regions on 2 DNA molecules; horizontal transfer of genes between bacteria
Genetic Recombination
Uptake and incorporation of naked DNA into a bacterial cell; chromosomal or plasmid DNA
Transformation
Transfer of bacterial genes by bacteriophage
Transduction
Transfer of genetic material from donor to recipient requiring close contact, mediated by sex pilus
Conjugation
Subdivision based on phenotypic differences
subspecies
Subdivision based on serologic differences
Serovarieties
Subdivision based on biochemical test result differences
Biovarieties
