Unit 2 lecture 7-10 Flashcards
Chemical Requirements for growth
- carbon
- hydrogen
- oxygen
- nitrogen
- phosphorus
- sulfur
Carbon purpose
make all of the macromolecules that cells need
hydrogen
make macromolecules and form hydrogen bonds
oxygen
mack macromolecules and metabolism
nitrogen
make amino acids, nucleic acids, ATP
Phosphorus
Make ATP, nucleic acids, phospholipids
sulfur
make amino acids, vitamins, disulfide bonds
Transport mechanisms
- Diffusion
- Active transport
Define diffusion
molecules move from area of higher concentration to areas of lower concentration
simple diffusion
limited, lipid soluble molecules
Facilitated diffusion
carrier protein bonds substances and changes shape. transport
Active Transport
Against concentration gradient or with but at a faster rate
(lower concentration to higher)
cell mediated transport
need carrier protein
group translocation
molecules transported altered in the process
endocytosis
phagocytosis and pinocytosis
phagocytosis
engulfment of whole cells/ large solids
Pinocytosis
vesicles of liquid are taken into cell
Physical requirements for growth
- temperature
- gas
- ph
- osmotic pressure
temperature requirements
most at 37 degrees celsius
minimum-optimum-maximum curve
gas requirement
CO2 and O2
Not all need oxygen
pH requirements
grow best in range 6-8
bacteria: 7-7.2
yeats/molds: 5-6
Osmotic pressure requirements
prefer isotonic conditions
concentration is the same inside and outside of the cell
what is binary fission
call division and reproduction
- with each round, cells double in number
Process of binary fission
- cell elongates/DNA replication of bacterial chromosome
- invagination of cell membrane and cell wall at midpoint
- cross walk formation
- cells separate
generation time
amount of time required for one bacterial cell to divide into two cells
Bacterial growth phases
- lag
- log
- stationary
- death
Lag phase of growth
cells adapting and little to no cell division
Log phase of growth
Rapid cell division, nutrients available, cells most vulnerable
Stationary growth phase
decreasing nutrients, increasing toxic products, cell death rate= cell production rate
Death growth phase
Nutrients depleted, increase toxic products, cell death rate>cell production
3 measurements of bacterial growth
- turbidity
- direct microscopic count
- standard plate count
turbidity measurement
measure cloudiness using spectrometer
direct microscopic count
bacterial cells within specific area counted using specialized slide
standard plate count measurement
bacterial sample diluted over and over again
colony count multiplied by soliton factor
Define sterilization
destruction of all forms of microbial life
define disinfection
destruction of pathogenic microorganisms
static
inhibit
cidal
kill
what does contact rate of killing mean
the same percentage of of cells die per time interval of treatment
7 factors affecting control methods
- size of microbial population
- amount of time agent used
- concentration of agent
- greater temperatures
- Ph extremes
- special protection
- presence of organic matter
4 mechanisms of action
- disruption of cell wall
- disruption of plasma membrane
- denaturation of proteins
- damage to nucleic acids
Disruption of cell wall
fragile cell that can result in lysis
Disruption of plasma membrane
agent damages lipids/proteins in cell membrane
content leakage
denaturation of proteins
alcohols, acids, heat damage proteins and enzymes
damage to nucleic acids
inhibit replication/transcription/translation
7 physical methods of control
- heat
- pasteurization
- dedication
- filtration
- radiation
- osmotic pressure
- low temps
Heat method of control
- superior method
- inactivates proteins
Why is moist heat superior to dry heat
penetrates better, denatures proteins
Pasteurization method of control
mild heat destroys pathogens
dedication method of control
dehydration inhibits bacterial growth
filtration method of control
physical separation of microbe form liquid or gas using membrane filter
radiation method of control
damage to proteins and DNA
Osmotic pressure method of control
highly concentrated solutions dehydrate microbes
refrigeration method of control
decreases bacterial enzyme activity and can’t reproduce
spectrum of resistance from lowest to highest
lipid envelope, gram +, no envelope, fungi, gram -, protozoa, mycobacterium, endospores
Chemical methods of control
- antiseptics and disinfectants
- work by disruption of plasma membrane and denaturation of proteins
- microorganisms are not equally effected by anti microbial chemicals
do most anti microbial chemicals sterilize
No
define antiseptic
chemicals applied to the body that inhibit/destroy microorganisms
define disinfectant
chemicals use don non living objects to kill/destroy microorganisms
superior chemical methods (kill everything)
- chlorine
- hydrogen peroxide
- glutearaldehyde
- formaldehyde
- gaseous sterilants
what is the filter paper method
- evaluates efficacy of chemical agent
- zone of inhibition: clear area around paper disks with no bacterial growth
3 factors leading to decrease in infectious disease
- improved methods of sterilization
- discovery and use of vaccines
- development of anti microbial drugs and antibiotics
define anti microbial drug
synthetic product made in laboratory
define antibiotic
natural product made by 1 microbe that inhibits or kills another microbe
what is spectrum of activity
specific group of organisms that specific agent is effective against
6 mechanisms of action
- inhibition of cell wall synthesis
- inhibition of protein synthesis
- disruption of nucleic acids
- disruption of plasma membrane
- inhibit folic acid synthesis
- inhibit fungal infections
Isoniazid and ethambutol
inhibit production and incorporation of mycolic acid into the cell wall of mycobacterium
inhibition of cell wall synthesis
- inhibits peptidase enzyme necessary to cross link glycan chains in peptidoglycan
drugs that inhibit cell wall synthesis
- penecillins
- cephalosporins
- bacitracin
- vancomycin
inhibition of protein synthesis
drugs interact with prokaryotic ribosomes and stop translation of proteins
drugs that inhibit protein synthesis
- aminoglycosides
- tetracycline
- chloramphenicol
disruption of nucleic acids
drugs interfere with dna or rna
drugs that disrupt nucleic acids
- quinolones
- rifampin
disruption of plasma membrane
drugs have specificity based on differences in membrane lipids
drugs that disrupt plasma membrane
polymyxins
inhibit folic acid synthesis
inhibit enzymes necessary to make folic acid
drugs that inhibit folic acid synthesis
- sulfanomides
- trimeothoprin
inhibition of fungal infections
eukaryotic
drugs that inhibit fungal infections
- polyenes
- Imidolzoles
- Grislofulvin
5 mechanisms of antibiotic resistance
- enzymes produced that inactivate drug
- membrane protein receptors altered and drug cannot enter cell
- membrane protein pumps drug out of cell
- mutations in cell target cite and drug cannot bind
- microbe develops an alternate pathway or enzyme
3 effects of drug resistance
toxicity
allergic reactions
suppression of normal flora
toxicity
drug can become toxic to people with prolonged use
allergic reactions
drug works as antigen
suppression of normal flora
drug can deplete normal flora and pathogens over take
kirby bauer test
- determine sensitivity of resistance
- antibiotic disks placed on agar plate
- the larger the sone of inhibition the better
- sensitive-resistant-intermediate
MIC Test
- determines minimum concentration of antibiotic that prevents growth
- serial dilutions of particular antibiotic are made
- 1st well that is clear=no growth
Define pathogen
organism capable of causing disease
define infection
invasion of pathogenic organisms in body
define invasiveness
pathogens ability to penetrate individuals tissue and establish itself
define infectious disease
altered state of health cause by pathogenic microorganisms
define sign
change in patient visible and measurable
define symptom
changes felt only by patient
define normal flora
microorganisms normally found on a given habitat on our body consistently
define transient microorganisms
organisms found on body only for brief periods of time
define mutualistic symbiont
host and microbes benefit
define commensal
microbes benefit
define opportunistic
microbes benefit, host is hurt
3 major interacting factors
- virulence of organism
- number of organisms
- status of persons immune system
6 virulence factors
- body site must be optimal for microbe
- adherence factors
- escape from bodies immune system
- direct invasion of host cell
- siderophores
- toxicity
Body site optimal for growth
growth requirements met
adherence factors
Components of cell wall
- fimbriae and capsules
escape from bodies immune system
anti-phagocytes structures: fimbriae and capsules impede phagocytosis
- genetic factors
direct invasion of host cell
pathogen invades and multiplies which kills cells
Siderophores
high affinity for iron may aid organism to remain in host
toxin production
exotoxins and endotoxins
exotoxins
- secreted proteins
- disease specific signs/symptoms
- antibody production
- can immunize against
- produce frequently due to plasmid/prophage
- produced mostly by gram +
endotoxins
- lipopolysaccharides
- same signs/symptoms
- released when organism is destroyed in host
- no ABs against
- can’t immunize against
- produced by gram - bacteria
define intoxication
directly ingest toxin
define infection
ingest pathogen which produces toxin
define pathology
study of disease
define etiology
cause of disease
define pathogenesis
development of disease
reservoirs
- continual source of pathogen
- human body, animals, water, soil, food
transmission routes
- how pathogen is spread
- contact, vehicle, animal
5 portals of entry
- respiratory tract
- gastrointestinal tract
- genitourinary tract
- skin and mucous membranes
- blood
4 phases of infectious disease development
- incubation
- prodormal
- illness
- convalescence
incubation period
time interval between infection and first signs/symptoms
prodromal period
short period of mild signs and symptoms
illness period
most acute, full blown disease, overt signs/symptoms
highest level of organisms
Convalescence period
recovery time, signs/symptoms subside
acute disease
disease develops rapidly for short duration.
chronic disease
disease develops slowly
milder but longer lasting symptoms
local disease
infection limited to one area of the body
systematic
infection spread throughout the body
primary
body’s defenses are overcome by pathogen
secondary
opportunistic bacteria causes infection after primary infection
inapparent
signs/symptoms non existent but infection still transmitted to others
define endemic
disease constantly present within geographic area
define epidemic
sharp increase in cases during specific period of time
define sporadic
disease occurs occasionally in random sporadic ways
define prevalence
percentage of population that contract disease at any given time
define incidence
percentage of population that contract disease during specific period of time
emerging infectious diseases
- diseases that are new or changing and increasing or expected to increase in future
- AIDS, E. coli, Streptococcus, Lymes, Anthrax
