Exam #1 Flashcards
What is the definition of The concept of spontaneous generation?
the hypothesis that living organisms arise from non-living matter; disproved by Louis Pasteur using the swan neck flask
Who was the scientist who disproved this concept using the swan necked experiment?
Louis Pasteur: the swan neck flask allowed air, but trapped the dust from entering the sterilized broth. It wasn’t until the dust was mixed with the broth that it became contaminated
Define the germ theory of diseases
the theory that microorganisms are the cause of many diseases
Who came up with the Hypothesis of the Germ theory of disease?
Louis Pasteur and/or Robert Koch
Who proved the germ theory of disease?
Robert Koch
Who Discovered antibiotics?
Alexander Flemming
What was the first antibiotic?
Penicillin; while studying the colonies of Staphylococcus that produced mold (Penicillium)
Who Discovered salvarsan? & Concept of Selective Toxicity?
Paul Elrich
What is salvarsan?
first antimicrobial drug used to fight syphilis
Who determined that Fermentation is the result of microbial activity?
Louis Pasteur
Who Came up with pasteurization?
Louis Pasteur
What is fermentation & pasteurization?
Fermentation:sugars converted from sugar to ethyl alcohol
Pasteurization: Heat-treat something to make it safer to drink/eat to destroy microbes ex. milk
Who Isolated pure cultures?
Robert Koch
Who Discovered Anthrax TB and Cholera?
Robert Koch
Who Made Vaccine against Cholera and rabies?
Louis Pasteur
Who was the First to Implement vaccination(smallpox)?
Edward Jenner
Who described Animacules (bacteria)?
Antoni van Leeuwenhoek
Who invented first compound microscope?
Robert Hooke
List & Describe 3 New Bacteria Diseases?
~Lyme Disease: mode: bite from a tick
~Toxic Shock Syndrome: mode: high absorbent tampons (TSST-1:is a superantigent released by staph aureus which recruits T-cells)
~Ecoli O157:H7: “hamburger ecoli” mode:eating contaminated food, mass production of meat
~Legionnaire’s Disease:mode:contaminated water supply that is resistant to heating & cholorination
List & Describe 3 New Viral Diseases?
~AIDS:”Acquired Immunodeficiency Syndrome”: HIV:mode:contaminated blood or tissue
~Ebola: “hemorrhagic fever”:ebola virus: infected body fluids, control measure is quarantine of active cases
~SARS:”Severe Acquired Respiratory Syndrome”: mode: contact with contaminated feces, person to person; zoonotic
~Hantavirus pulmonary syndrome: mode: inhalation of aerosolized rodent urine or feces
What are the main causes attributed to the emergence of new diseases?
~Change of Lifestyle: Ecoli O157:H7 (slaughter houses); tampons
~Closer contact with animals: expansion of city suburbs to rural areas
List the main causes attributed to the emergence of Old re-emerging diseases?
~Resistant to antibiotics (MRSA, TB)
~Neglecting Vaccination (MMR)
~Increase # of individuals with weakened immune systems (HIV+, elderly, adult diabetics)
~Increase of international traffic
What is a gene?
section of DNA that codes for a specific trait (heredity)
What is the monomer of Genes (what are genes made of)?
nucleotides: nitrogenous base, phosphate group, carbon sugar
What do genes code for?
Genes code for proteins which ultimately expresses a phenotypic trait
What is a prion?
protein ONLY
What is the central dogma in molecular biology?
~DNA Replication: helicase unwinds the ds; RNA primase adds complementary strand; DNA polymerase reads template strand from 3’ to 5’ & adds nucleotides from 5’ to 3’; DNA polymerase removes RNA primers & replaces with DNA
~Transcription (DNA to mRNA): done by RNA polymerase & transcription factors in the nucleus; a 5’ cap and a poly-A tail is added to the pre-mRNA chain; splicing occurs.
~Translation: mRNA gets translated in a ribosome in cytoplasm; ribosome reads the start codon (AUG); tRNA binds to the amino acid residue to add the polypeptide chain being synthesized; ends with a stop codon (UAA, UGA, or UAG).
How did we get rid of small pox and plague?
Smallpox:prevention (immunization-vaccines & quarantine)
Plaque: used antibiotics
causative agent of Ebola
Filoviridae ebolavirus
causative agent of Legionnaire’s Disease
legionella pneumophilia
causative agent of Lyme’s Disease
borrelia burgdorferi
increase in deer & human population in wooded areas
causative agent of Toxic Shock Syndrome
Staphylococcus Aureus
causative agent of EHEC
ecoli 0157:H7
mass production of meat
causative agent of SARS
coronavirus (SARS-CoV)
causative agent of Hantavirus
hantavirus
intrusion of human into rodent niche
List 6 reemerging diseases
Drug Resistant Malaria Plague Diphtheria Multidrug Resistant TB Ebola Hemorrhagic fever Typhoid fever
What is the difference between viruses and cells? Why are viruses not considered as cells?
living organism essentials are absent. cannot reproduce without having a host cell cannot metabolize can not grow do not produce waste products Lack ribosomes Only a single form of nucleic acid
What do viruses have in common with Cells?
Viruses and living cells both have genetic material and protein (makes up their capsid).Both can also mutate.
What are the structural and functional resemblances between Prokaryotic cells and Eukaryotic cells?
Cell membrane & Cytoplasm
compare prokaryotic cell versus eukaryotic cells on the basis of their:structural differences
Prokaryotes: nuceloid, plasmids, flagella, glycocalyx, and peptidoglycan.
Eukaryotes: nucleus, Chromosomes (many), mitochondria, nuclear membrane, organelles.
compare prokaryotic cell versus eukaryotic cells on the basis of their: functional differences differenciation, reproduction exchange of genetic materials
Prokaryotes: reproduce via binary fission(divide). Have sex pili that aid in conjugation(exchange genetic info). DNA replication occurs in the cytoplasm.
Eukaryotes: cells divide(mitosis). Meiosis (exchange genetic info) DNA replication in nucleus.
compare prokaryotic cell versus eukaryotic cells on the basis of their: metabolic differences: food uptake, generation of energy
Both have same metabolic pathways. (Cellular Respiration)
Prokaryotes: metabolic processes occur in the cell membrane.
Eukaryotes: metabolic processes occur in the mitochondria and/or chloroplasts.
Role of flagella
aid in movement; made of flagellin
works like a propeller {run(anticlockwise) & tumble (clockwise)}
Role of Pili:
FOUND MAINLY IN GRAM NEGATIVE
fimbria-like structure present on fertile cells used for attachment to specific structures (twitch & glide)
Role of sex pilus:
used during conjugation (DNA transfer-involves plasmids)
Role of glycocalyx:
composed of polysaccharides (capsule or slime layer)
~nonspecific attachment(form biofilm)
~accumulate nutrients & water loss
~protection (from phagocytosis by macrophages & neutrophils)
Role of Cell Wall:
rigid structure that determines shape and prevents cell from bursting
What are the differences that can be found b/w gram positive versus gram negative?
gram positive:stain purple, thick peptidoglycan layer, no periplasm, teichoic acids present, less resistant to antibiotics
gram negative:stain red, thin peptidoglycan layer, has a periplasm,LPS present & outer membrane, more resistant to antibiotics
What is LPS ,where is it found ?
lipopolysaccharide
its an additional outer layer made up of lipids and sugars. LPS prevents the bacteria from retaining the gram stain. LPS contains an endotoxin (LIPID A) that is toxic to humans
LPS in lungs:
inflammation;release fluids;lung damage
LPS activate macrophages:
fever
reduction of arteries in heart
activate T-helper cells; drop in blood pressure;shock
LPS in blood:
disseminate intravascular coagulation (DIC) by activating clots
internal hemorhage
What are the 3 different ways of acquisition of genetic material in bacterial cells?
Transformation
Transduction
Conjugation
Transformation
when a bacterial cell intakes a segment of DNA from its environment. Recombination between the segment and host chromosome occur and when the cell splits one portion contains the recombinant DNA
Transduction
intraspecific
transfer of bacterial gene via a bacteriophage
Conjugation
interspecific gram+:receptor & protein gram-:use pilus
bacterial cells fuse and part of the genetic material of one cell is passed to the other cell and recombination occurs
ex MRSA with VRE
Explain what is happening in bacterial cells during the lag phase, the log phase and the stationary phase.
Lag phase: little or no cell growth.Replicating/Metabolically active.
Log Phase: cells are active and being to divide. Rapid growth (binary fission).
Stationary phase: slow down of growth. This is where are limited resources for cells. waste also slows down growth
During which phase are antibiotic produced ?
stationery phase
5 targets of antibacterial drugs?
cell wall nucleic acid synthesis protein synthesis metabolic pathways cell membrane integrity
Tetracyclines
target protein synthesis
Chloramphenicol
target protein synthesis
Amoxicillin
target cell wall synthesis (beta lactam drugs)
Sulfanilamide
target metabolic pathways
Streptomycin
target protein synthesis
Rifamycin
target nucleic synthesis
Fluoroquinolones
target nucleic synthesis
PolymyxinB
target cell integrity
Bacitracin
target cell wall synthesis (beta lactam drugs)
Isoniasid
target cell wall synthesis (Mycobacterium)
Vancomycin
target cell wall synthesis (beta lactam drugs)
Methicillin
target cell wall synthesis (beta lactam drugs)
Erythromycin
target protein synthesis
Binary Fission
when a prokaryotic cells dna attacks to the cell membrane, replicates, and then split to form to daughter cells
What are antimicrobial drugs?
chemically synthesized drugs that inhibit growth or kill microorganisms.
Differentiate between vertical evolution and horizontal evolution in the acquisition of antimicrobial resistance
Vertical evolution is from mother cell to daughter cell (intraspecific). Horizontal evolution is from one cell to another cell (conjugation: interspecific)
List four mechanisms of antimicrobial drug resistance & specific examples?
efflux pump
alter targets
Decreasing uptake of drugs
Drug-inactiviting enzymes
Which of the following groups of microorganisms produces antibiotics?
a. Penicillium
b. Streptomyces
c. Bacillus
d. all of the above
e. a and b
D. All of the above
An antibiotic made by microorganisms and modified by chemists is called ___________
Semi-Synthetic
A high therapeutic index drug is
a. more toxic to the patient.
b. less toxic to the patient.
c. has no effect on the patient.
d. has no effect on the pathogen.
B.Less toxic to the patient
Drugs that are bacteriostatic Kill or Inhibit growth of bacteria?______
inhibit growth
Antibiotics that affect various strains of Gram-positive bacteria and various strains of Gram- negative bacteria are called
a. isolate usable.
b. stress-induced.
c. narrow spectrum.
d. broad spectrum.
D.broad spectrum
Define what is the half life of a drug?
time it takes for the body to eliminate one half of the original dosages in the serum. The longer the half life of a drug the less is the frequency of doses that are required to maintain an effective level in the body
Which group of Antibiotics that are most likely to disrupt the normal flora are termed a narrow spectrum of activity Or broad spectrum of activity?
Broad Spectrum of activity
List the three major side effects caused by antimicrobial agents
allergies, toxic at high concentrations, suppression of normal flora
The arsenic compound that proved highly effective in treating syphilis was called__________
Salvarsan
Which bacteria have an innate resistance to penicillin?
Mycoplasma
Prontosil effectively acted on streptococci when the drug was split by enzymes to produce_________________
sulfanilamide
One of the earliest antimicrobials isolated from a bacterium was_______________
Streptomyces
List the drugs that target peptidoglycan
penicillin, cephalosporin, vancomycin, bacitracin
Penicillin-binding proteins
a. primarily function in the cell to bind to beta-lactam drugs.
b. are enzymes.
c. are involved in cell wall synthesis.
d. inhibit non-growing bacteria.
e. b and c
E. B&C
What is the Role of Beta-lactamases?
breaks the beta-lactam ring
What is the role of of aminoglycosides?
Bactericidal against aerobic and facultative bacteria; binds to the 30s ribosomal subunit, blocking the initiation of translation and causing the misreading of mRNA. Toxicity limits the use. Resistance is due to a plasmid encoded inactivating enzyme, alteration of the target molecule, or decreased uptake by a cell.
What are The major classe(s) of antibiotics that inhibit protein synthesis is/are_______________
aminoglycosides, tetracyclines AND macrolides
Antibiotic that act as Inhibitors of protein synthesis typically key on________________
ribosomes
Folic acid is ultimately used in the synthesis of_____________________
coenzyme
Sulfonamides are similar in structure to_____
PABA
Mycolic acids are targeted by isoniazid in the treatment of______________
M. tuberculosis
Bacteria may become antibiotic resistant by four different ways which are?
1) drug-inactivating enzymes
2) alteration in the target molecule
3) decreased uptake of the drug
4) increased elimination of the drug
Acquisition of antimicrobial resistance due to spontaneous mutation is called______________
Vertical evolution
The most common method of transfer of antimicrobial resistance is through the use of_______________
R-plasmid
The key characteristic of a useful antimicrobial is selective toxicity.
True
Antimicrobials that have a high therapeutic index are less toxic to the patient.
True
Broad spectrum antibiotics have minimal effect on the normal flora.
False
Certain antimicrobials may be life-threatening.
True
Drugs that target peptidoglycan do not effect eukaryotes.
True
Beta-lactam drugs are only effective against growing bacteria.
True
Antimicrobial resistance can be due to spontaneous mutation or gene acquisition.
True
Viruses are very effectively treated with an antibiotics.
False
Is their any association between the generation time of a specific bacterial pathogen and it’s the length of period of treatment ? Explain your argument (keep in mind that drugs are more efficient against growing cells)
Length of treatment does depend on generation time. The longer the generation time for a bacteria (the slower it metabolizes) the longer time for treatment.
Is there any association with the half life of an antibiotic and its number of daily prescription dose ? Explain your argument
Yes, because the longer the half-life the least number of daily prescription doses have to be taken and vice versa
