exam 3 Flashcards
flow of genetic information
transcribed –> RNA –> translation –> protein
what is DNA transcription
rewriting of the message in DNA into a molecule called RNA
what do ribonucleotides do…
make RNA
deoxyribose v. ribose
deoxy is double stranded, RNA is single, thymine v uracil
rRNA
ribosomal RNA
tRNA
transfer RNA that brings the amino acids to the ribosome to make protein
mRNA
messenger RNA that reads message from DNA to make a protien
what are mutations?
change in the DNA base sequence
what is the genotype
genetic compostition of an organism
phenotype
expressed characteristics
spontaneous mutation
occurs naturally
induced mutation
induced by a chemical or physical agent
silent mutation
change in genotype but not phenotype
frameshift mutation
removal or insertion of a base, everything after will be incorrect
what do genes do?
code for enzymes that catalyze reactions
what do enzymes do
catatlyze reactions that produce products for a certain phenotype
chemical mutagenic agents
smoking
how does smoking cause cancer?
chemical inducers in the smoke will induce mutations in individual lung cells, other chemicals called promoters will promote replication, double mutation in specific genes in a single cell will initiate cancerf
transformation is…
uptake in transformation of naked DNA, taken up by a cell and expressed
in transformation, what is required for the DNA to be transferred?
the cell has to die to transfer DNA
conjugation
sex in bacteria
what do some bacteria use to reproduce
a sex pili
gram positive conjugation
no sex pilus, sex pheromones are used, identified in streptococci
why do streptococcus strains produce pheromones?
to attract a certain plasmid that it needs
what is a CIA
clumping inducing agent and a sex pheromone
what does CIA do to the strain WITH the plasmid
stimulates it to produce a sticky substanec
what is the state of donor/recipient cells in transduction?
the donor is dead, the recipient is alive
what happens when mistaken packaging of DNA occurs
the DNA will be transferred to a new cell and it cannot lyse the new cell because of one way gene transfer
restriction enzymes
enzymes that cut DNA in a staggered pattern
what are the 3 types of control of microorganisms
physical, chemical, antimicrobial
sterilization (definition)
killing or removal of all organism from a given area
6 physical methods of control
heat, filtration, desiccation, radiation, osmotic pressure, low temperature
heat methods of control (5)
moist heat, dry heat, incineration, boiling water, pasteurization
can organisms survive an autoclave?
no
two types of radiation
ultraviolet, ionizing
osmotic pressure example
added salt creates osmotic pressure problems
lyophilization
freeze drying
physical methods of sterlization
moist heat under pressure, dry heat, incineration, filtration, ionizing radiation
antiseptic
chemical used topically to inhibit or destroy microorganisms
disinfectant
chemical used on non living objects to inhibit or destroy microorganisms
sanitizer
chemical used to reduce bacterial numbers to a safe level according to public health requirements
major targets of chemical control methods
cell membranes, cellular proteins
chemical methods of control/ DISINFECTION
- concentration of disinfectatnt/antiseptic
- time
- temperature
- nature of surrounding medium
chemical methods of control/AGENTS
- phenol
- cresol
- alcohols
- soaps and detergents
- formaldehyde
- hydrogen peroxide
- bleach
- ethylene oxide
methods of sterilization
moist heat under pressure, dry heat, incineration, filtration, ionizing radiation, ethylene oxide
chemotherapy
destroying disease organisms without destroying the host
antibiotics
by products of metabolism used in chemotherapy, directed toward bacteria
what is an example of chemically synthesized chemotherapeutic agents
sulfonamides
what are the criteria for usefulness of control
low in toxicity to host while destroying or inhibiting the disease organism
host should not become allergic
disease organism should not become resistant
antimicrobials to know
penicillin, erythromycin, polymyxin B, sulfanilamide, ciprofloxacin
what is antimicrobial resistance
one of the biggest problems that occurs because physicians prescribe antimicrobials/biotics for viral infections
measures to minimize antimicrobial resistance
avoidance of indiscriminate use
dose should be high
combination of antimicrobial agents
possible complications of antimicrobial
allergy
toxic side effects
destruction of normal flora
contamination
microorganisms are present
infection
pathogenic microorganisms are present in the body, may or may not be causing harm
disease
when microorganisms do harm to the host
endemic
disease organism is constantly in a certain geographic location
epidemic
relatively large number of cases of a disease develop in a community within a short time
pandemic
a worldwide epidemic
virulence
measure of pathogenicity
pathogenicity
ability of a microorganism to cause disease
nosocomial infection
hospital acquired infection
how pathogens enter and leave the body
- respiratory tract
- GI tract
- skin and mucous membrane
- genitourinary tract
- blood
invasive mechanisms of bacteria
capsules
fimbriae
exotoxins
and enzymes
factors in the development of disease
portal of entrance
virulence
ability to flourish outside the body
