Week 2: Singlecelled and Multicelled Organisms Flashcards
Define homeostasis and give 2 examples.
Regulation of the internal environment to maintain a constant
Examples:
Electrolyte concentration
Sweating to reduce temperature
Define metabolism.
Transformation of energy by converting chemicals and energy into cellular components (anabolism) and decomposing organic matter (catabolism)
Define growth.
Maintenance of a high rate of anabolism than catabolism; a growing organism increases in size all of its parts, rather than simply accumulating matter
Define adaptation.
The ability to change over time in response to the environment; fundamental to the process of evolution and is determined by the organism’s heredity, diet, and external factors
Define reproduction.
The ability to produce new individual organisms, either asexually from a single parent organism, or sexually from two parent organisms
What are the 2 major cell types? List the organisms associated with each.
Prokaryotic: bacteria
Eukaryotic: protists, fungi, plants, and animals
Identify this bacteria shape.
https://upload.wikimedia.org/wikipedia/commons/thumb/d/d3/Staphylococcus_aureus_VISA_2.jpg/440px-Staphylococcus_aureus_VISA_2.jpg
Coccus
Identify this bacteria shape.
https://upload.wikimedia.org/wikipedia/commons/b/b9/Bacillus_subtilis_Gram.jpg
Bacillus
Identify this bacteria shape.
https://upload.wikimedia.org/wikipedia/commons/thumb/9/9d/Cholera_bacteria_SEM.jpg/440px-Cholera_bacteria_SEM.jpg
Vibrio
Identify this bacteria shape.
https://upload.wikimedia.org/wikipedia/commons/thumb/9/9f/Spirillen.jpg/440px-Spirillen.jpg
Spirillum
Identify this bacteria shape.
https://ucmp.berkeley.edu/bacteria/leptospira.jpg
Spirochete
What is the key difference between Gram positive and negative stains?
Gram positive bacteria appear purple under the microscope and Gram negative bacteria appear red
What are the 4 types of bacteria? Give examples for each.
Respiratory:
TB (M. tuberculosis)
Pneumonia (S. pneumoniae)
Enteric:
Cholera (V. cholera)
Salmonella (S. enteriditis)
Typhoid (S. typhi)
Common food poisoning (E. coli)
STDs:
Syphilis (T. pallidum)
Gonorrhea (N. gonorrhoeae)
Systemic:
Leprosy (M. leprae)
Lyme disease (B. burgdorferi)
Pertussis/”whooping cough” (B. pertussis)
Give details about the 9 techniques used in bacterial identification and classification:
Microscopic morphology
Macroscopic morphology
Phsyiological/biochemical characteristics
Chemical analysis
Serological analysis
Genetic and molecular analysis
G + C base composition
DNA analysis using genetic probes
Nucleic acid sequencing and rRNA analysis
Microscopic morphology: traits that can be valuable aids to identification are combinations of cell shape and size; electron microscope studies can pinpoint additional structural features
Macroscopic morphology: appearance of colonies, including texture, size, shape, pigment, speed of growth, and patterns of growth in both and gelatin media
Physiological/biochemical characteristics: enzymes and other biochemical properties of bacteria are fairly reliable and stable expressions of the “chemical identity” of each species; diagnostic tests determine the presence of specific enzymes and assess nutritional and metabolic activities
Chemical analysis: analyzing the types of specific structural substances that the bacterium contains, such as chemical composition of peptides in the cell wall and lipids in membranes.
Serological analysis: bacteria display molecules called antigens that are recognized by the immune system; one immune response is to produce antibodies designed for the antigens and these antibodies can be used to identify bacteria
Genetic and molecular analysis: examining the genetic material itself has revolutionized the identification and classification of bacteria
G + C base composition: overall percentage of guanine and cytosine in DNA is a general indicator of relatedness because it is a trait that does not change rapidly; bacteria with a significant difference in G + C percentage are less likely to be genetically related
DNA analysis using genetic probes: possible to identify a bacterial species by analyzing genetic material; uses small fragments of DNA (or RNA) called probes that are complimentary to specific DNA sequences from a particular microbe; if the probes bind to the DNA after being added to a special plate, the unknown species is closely related and may be identifiable
Nucleic acid sequencing and rRNA analysis: one of the most valuable indicators of evolutionary relatedness is the sequence of nitrogen bases in ribosomal RNA; tend to remain stable in nucleic acid content over long periods; any major differences is likely to indicate some distance between ancestry; effective for differentiating general group differences and can identify species
What are the 3 details related to fungi? Give examples of the 3 types.
Any member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds (as well as more familiar mushrooms)
Classified as a kingdom (“Fungi”) and is separate from plants, animals, protists, and bacteria
One major difference is that fungal cells have cell walls that contain chitin, unlike the cell walls of plants and some protists (which contain cellulose) and unlike the cell walls of bacteria
Example:
Systemic:
Histoplasmosis
Cryptococcosis
Dermal:
Ringworm (tinea capitis)
Opportunistic:
Candida
Aspergillus
What are the 4 details related to viruses? Give examples of the 5 types.
Not cells (instead, they are obligate intracellular parasites, meaning they need host-cell “machinery” to replicate)
Comprised of nucleic acid (RNA or DNA) making up the genome
Usually have a protein coat (capsid) to protect the nucleic acid
May have an outer protective coat (envelope)
Examples:
Respiratory:
Colds (URIs)
Influenza
Childhood diseases:
Measles (rubeola)
German measles (rubella)
Mumps
Chickenpox
Cytomegalovirus (CMV)
Epstein Barr virus (EBV)
GI system:
Hepatitis viruses (A, B, C, D, E, G)
Viral diarrheas
Neurological diseases:
Encephalitis (EE, WEE, etc.)
Aseptic meningitis
Rabies
Poliomyelitis
Systemic:
Yellow fever
Smallpox
Hemorrhagic fevers
What are the 3 details related to prions? Give 5 examples of them.
A small proteinaceous disease-causing agent that is believed to be the smallest infectious particle
Neither bacterial nor fungal nor viral and contains no genetic material
Held responsible for a number of degenerative brain diseases
Examples:
Mad cow disease
CJD
Fatal familial insomnia
Kuru
An unusual form of hereditary dementia
What is 1 detail related to parasites? Give examples of the 3 types.
An organism that lives in or on another organism (host) and benefits by deriving nutrients at the host’s expense
Examples:
One-celled:
Malaria
Trypanosomiasis (African sleeping sickness)
Toxoplasmosis
Giardiasis
Multicellular:
Internal:
Round worms
Tape worms
Flukes (schistosomiasis)
External:
Lice
Mites
Scabies
Explain how schistosomiasis transmits from human to alternate host to human.
- Eggs are laid in water from waste of infected human
- Eggs hatch releasing miracidia
- Miracidia penetrate snail tissue
- Sporocysts in snail (successive generations)
- Cercariae released by snail into water and free swim
- Penetrate skin of uninfected human
- Cercariae lose tails during penetration and become schistosomulae
- Circulation
- Migrate to portal blood in liver and mature into adults
- Worms travel through waste into water source and cycle starts again
What are Koch’s postulates?
- Microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms
- Must be isolated from a diseased organism and grown in pure culture
- Cultured microorganism should cause disease when introduced into a healthy organism
- Must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent
What are the 9 characteristics of the ideal antimicrobial drug?
- Selectively toxic to microbe but nontoxic to host
- Soluble in body-tissue distribution; crosses blood-brain barrier
- Remains in body long enough to be effective; resists excretion and breakdown; requirement for just single dose is ideal
- Long shelf life, no need for refrigeration
- Does not lead to resistance
- Cost not excessive
- Hypoallergenic
- Microbiocidal rather than microbiostatic
- Doesn’t suppress normal flora
What are the 5 modes of antibiotic action? Give examples of antibiotics that use each mode.
- Inhibition of cell wall synthesis: penicillins, cephalosporins, bacitracin, and vancomycin
- Inhibition of protein synthesis (occurs during translation): choleramphenicol, erythromycin, tetracylines, and streptomycin
- Inhibition of nucleic acid replication and transcription: quinolones and rifampin
- Injury to plasma membrane: polymyxin B
- Inhibition of synthesis of essential metabolites: sulfanilamide and trimethoprim
What is drug resistance? What causes the development of resistance mutants? Give examples.
Relative or complete lack of effect of antimicrobial against a previously susceptible microbe (increase in MIC)
Misuses of antibiotics results in development of resistance mutants:
Examples:
Using outdated or weakened antibiotics
Using antibiotics for the common cold and other inappropriate conditions
Using antibiotics in animal feed
Failing to complete the prescribed regiment
Using someone else’s leftover prescription
What are the 2 groups of reason for antibiotic overuse? Give reasons for each group.
Patient concerns:
Want clear explanation
Need to return to work
Physician concerns:
Patient expects antibiotic
Diagnostic uncertainty
Time pressure
What are the gaps in knowledge regarding antibiotic resistance?
- Limited national, state, and federal capacity to detect and respond to urgent and emerging antibiotic resistance threats
- Currently, there is no systematic international surveillance of antibiotic resistance threats
- Data on antibiotic use in human healthcare and in agriculture are not systematically collected
- Programs to improve antibiotic prescribing are not widely used in the U.S.
- Advanced technologies can identify threats much faster than current practice
What are 4 diseases that have resistance beyond typical bacteria?
- Imidazole-resistant Candida spp.
- Multidrug-resistant tuberculosis
- Multi-drug resistant malaria
- Anti-viral resistant influenza
What are different molecular ways bacteria can become antibiotic resistant?
Limit uptake of drug
Modify drug target
Inactivate a drug/drug’s effects
Pumping out from the cell
For six diseases, list the agent and their antibiotic resistance.
- Pneumonia: S. pneumoniae; penicillin
- Dysentery: S. dysenteriae; multiple resistances
- Typhoid: S. typhi; multiple resistances
- Gonorrhea: N. gonnorrhoeae; penicillin and tetracycline
- Tuberculosis: M tuberculosis; rifampicine and INH
- Nosocomial infections:
S aureus; methicillin, vancomycin
E species; vancomycin
Klebsiella, pseudomonas; multiple resistances
What are medical problems associated with anti-microbial resistance?
- Cancer chemotherapy
- Complex surgery
- Rheumatoid arthritis
- Dialysis for end-stage renal disease
- Organ and bone marrow transplants
What are the 5 things the government can do regarding antimicrobial resistance?
- Antimicrobial drugs pose obstacles in “market based” healthcare system because they are used only briefly (unlike drugs used to treat chronic conditions)
- Since resistance develops and a firm’s patents will expire, drug manufacturers are under pressure to realize short term profits which pose long term health risks
- Development of cross resistance can occur as a result of inappropriate use of another drug product, thus one firm which overpromotes their medication can erode the usefulness of another firm’s drug
- Patent expiration encourages overuse of antimicrobials
- Congress has proposed solutions: firms might receive extended patent protection or some other incentive for development of a new antibiotic
Why do Gram positive bacteria turn purple and Gram negative bacteria turn red?
Difference in the ability of the cell wall to retain the violet dye
To be held, the dye needs high peptidoglycan content and the Gram positive stains have it while Gram negative have higher lipid content
What antibiotic resistant methods do intrinsic (3) and equidistant (2) use?
Bacteria with intrinsic resistance: limiting drug uptake, drug inactivation, and drug efflux
Bacteria with equidistant mechanisms: drug inactivation and drug efflux
What antibiotic resistant methods do Gram negative (4) and positive (2) use?
Gram negative bacteria use all four mechanisms whereas Gram positive bacteria can’t limit drug uptake (because they don’t have an LP sort of membrane) and don’t have the capacity for certain types of drug efflux mechanisms
