The flashcards below were created by user
on FreezingBlue Flashcards.
Requirements for bacterial growth
- Temp pH (between 6.5-7.5)
- osmotic pressure
- chemicals (carbon, nitrogen, sulfur. Phosphorus, trace elements)
Growth occurs only where high concentrations of O2 have diffused into the medium
Obligate Aerobes – Oxygen Required
Growth is best where most O2 is present, but occurs throughout tube
Facultative Anaerobes – Both aerobic and anaerobic, greater with O2
Growth occurs only where there is no O2
Obligate Anaerobes – Only Anaerobic, ceases in the presence of O2
Growth occurs evenly; O2 has no effect
Aerotolerant Anaerobes – Only Anaerobic, but continues in the presence of O2
Growth occurs only where a low concentration of O2 has diffused into medium
Microaerophiles – Only Aerobic growth, O2 required in low concentrations
Biofilms: what they are and what they do
- Microbial communities
- Usually found on solid substrates submerged in or exposed to an aqueous solution
- Cell to cell communication allows bacteria to coordinate their activity forming a functional community
- Resists antimicrobials
What does a buffer do?
maintains pH by neutralizing acid (alkalinity)
time required for a bacterial population to double
Name the phases of bacterial growth
- lag phase
- exponential phase
- stationary phase
- death phase
What happens in the lag phase of bacterial growth?
starts to produce enzymes
What happens in the exponential phase of bacterial growth?
increase in population (doubles replication)
What happens in the stationary phase of bacterial growth?
Using up nutrients (the number of bacteria dividing equals the number of bacteria dying)
What happens in the death phase of bacterial growth?
removing vegetative pathogens from hard surfaces, not endospores
antimicrobial substances that are applied to living tissue to reduce the possibility of infection
inhibiting, not killing microbes (whatever is left continues to grow)
removing all microbial life
killing organisms that cause illness
The effectiveness of disinfectant treatment depends on:
- Number of microbes
- Environment (organic matter, temp, biofilms)
- Time of exposure
- Microbial characteristics
What are the various ways to sterilize?
- Low Temp Freezing
Name three common chemicals for sterilization
- Phenols: Lysol
- Alcohols: Isopropyl Alcohol
- Halogens: Betadine
population of cells derived from a single cell that are identical
genetically different cells within a species
A subset of a bacterial species differing from other bacteria of the same species by some minor but identifiable differences
What are the Phenotypic Identification Methods?
- Determines type of protein made
- Determines when it will turn on and off (how it controls the gene)
Serology: Slide agglutination test
- Technique relying on specific interaction between antibodies and antigens
- Some available for rapid detection (gonorrhea) Bacteria A vs Bacteria B
- protein attaches or not
What is Burkholderia and why it is dangerous in the hospital?
- Extraordinary nutritional spectrum
- Degrades more than 100 different organic molecules
- May grow in disinfectant
- Can live on a variety of items
What is an opportunistic pathogen?
- Live outside normal habitat
- Cause problems outside their habitat
What are the characteristics of Enterobacteriales (enterics)?
- Facultatively anaerobic
- Normal part of the gut flora found in the intestines of humans
Name some examples of Enterobacteriales (enterics):
- Esherichia coli
- Salmonella – typhoid, salmonellosis Shigella - dysentary
- Klebsiella – K pneumonia – most common nosocomial URI
Characteristics of Pseudomonas aeruginosa
- forms biofilms
- resistant to most antibiotics
Characteristics of Enterobacter:
- most frequently isolated in hospitalized patients
Characteristics of Shigella:
usually the cause of epidemics of dysentery
Characteristics of Bacillus:
- endospore producing
- obligate anaerob
- forms capsules
Characteristics of E. Coli
- transmission through food/water
- provides vitamin K
Characteristics of Klebsiella:
- rod-shaped bacteria
- prominent polysaccharide-based capsule
The bacteria that causes ulcers?
Campylobacter jejuni; why is it important?
- Main cause of bacterial foodborne disease in many developed countries.
- Importance: produces a toxin that hinders cells from dividing and activation the immune system
Staphylococcus; examples of what it causes and what makes it so dangerous
- Causes staph aureus, MRSA
- Produces numerous toxins that allows it to damage tissue
- Develops ABX resistance
Streptococcus, how to distinguish between beta, alpha, gamma
- Beta-hemolytic: leaves a clear zone around colony
- ·Strep throat
- Alpha-hemolytic: forms a green zone around colony
- Gamma-hemolytic: no hemolysis
General Characteristics of Viruses
- Obligatory (obligated to be in a cell to grow and reproduce
- Contain DNA or RNA
- Contains a protein coat
- Most viruses infect only specific types of cells in one host
- Host range determined by specific host attachment
What determines which cells a virus binds to (infects)
- Receptor on a host cell site (ligand) attaches to virus binding site
- Only binds to certain cells
- If it can’t get into the cell it can’t replicate
Name the steps of Multiplication of animal virus’
What is attachment in the multiplication process of animal viruses
attachment to cell membrane via protein receptors
What is entry in the multiplication process of animal viruses
receptor-mediated or fusion
What is uncoating in the multiplication process of animal viruses
separation of viral nucleic acid from protein coat in vesicle
What is biosynthesis in the multiplication process of animal viruses
production of nucleic acid and proteins
What is maturation in the multiplication process of animal viruses
- protein transported into nucleus
- nucleic acid and proteins assemble
What is release in the multiplication process of animal viruses
virus transported to plasma membrane and released by budding or rupture
virus remains in asymptomatic host cell for long periods
Disease process occurs over a long period; generally fatal
What are prions?
proteins that are resistant to chemical biocides
The study of what genes are, how they carry information, how information is expressed, and how genes are replicated
Three types of RNA
What is the messenger function of RNA
intermediate between DNA and Protein
What is the Ribosomal function of RNA?
reads mRNA and synthesizes protein
What is the Transfer function of RNA?
transports amino acids to the ribosome
a change in the genetic material (single nucleotide mutation that may or may not affect the protein
What are the causes of mutations?
- mistake during DNA replication
- environmental, chemical, radiation...
What type of genetic transfer occurs during reproduction between generations of cells (parent à daughter cells
vertical gene transfer
What type of genetic transfer occurs during movement of DNA between bacteria and same generation (daughter à daughter cells)
Horizontal gene transfer
What type of genetic transfer occurs during the uptake and incorporation of DNA from a dead cell into a living cell
What type of genetic transfer occurs during a Transfer of a plasmid to another cell
Name the flow of genetic information
DNA - transcription - RNA - translation - protein
The flow of genetic information when DNA converted to RNA
The flow of genetic information when RNA converted to protein
The flow of genetic information when duplication of DNA making 2 chromosomes from 1
Cocci and Bacilli are gram?
This type of bacteria:
Cannot be gram stained
Distinctive cell wall: outer most layer is not LPS but a waxy water resistant layer
Few antimicrobial drugs can enter the cell
Mycobacterium: M. Tuberculosis, M. Leprae
Evaluation of disinfectants by the disk-diffusion method
- Zone of inhibition
- Gram+ zone reacts to all Gram-
- E-Coli: chlorine and phenylphenol Pseudomonas: chlorine only
Genus Mycobacterium, Species?
Genus Escherichia; Species ?
Genus Salmonella; Species ?
Genus Pseudomonas; Species?
Genus Herpes Simplex Virus; Species ?