microbiology

Question 1

what is microbiology?

Answer 1

study of microorganisms

Question 2

what are microorganisms?

Answer 2

-bacteria, fungi, protozoa, viruses

Question 3

what microorganisms are prokaryotic?

Answer 3

bacteria

Question 4

what microorganisms are eukaryotic?

Answer 4

fungi and protozoa

Question 5

what microorganisms are not cellular?

Answer 5

viruses

Question 6

what are bacteria?

Answer 6

ancient, primitive, simple, small

• lack membrane organelles
• up to 1 billion species!

Question 7

nomenclature for bacteria?

Answer 7

binomial system of naming

genus, species, serotype

Question 8

classification basis for bacteria?

Answer 8

• oxygen requirements (aneorobes vs. aerobes)
• metabolism (light energy, chemical energy)
• differential staining (gram + vs gram -)
• motility (flagella)
• pathogenicity (enterohemorrhagic, release toxins)
• morphology (cell structure and colony shape)

Question 9

cell morphology for bacteria? (size, shape, groupings)

Answer 9

• size (2-10 um)
• shape: spheres, rods, spirals
• groupings: individual, pairs, tetrads, chains, clusters, stacks

Question 10

bacterial cell structure?

Answer 10

PROKARYOTIC

• circular DNA (not enclosed in nucleus)
• cell envelope= cell membrane and cell wall (phospholipid bilayer made of peptidoglycan)
• gelatinous capsule (protection/attachment)
• may have flagella (for locomotion) or pili (for attachment/transfer of genetic material to other bacteria)

Question 11

bacteria growth? (how does it grow)

Answer 11

divide by binary fission (mitosis)
-may form highly resistant dormant cells called endospores (can withstand extreme hot/cold, poisons, lack of nutrients for long time!)

Question 12

ecology of bacteria?

Answer 12

most numerous and pervasive organism on earth.. ubiquitous!

-many are symbiotic (live in or on other organisms)

Question 13

normal flora are?

Answer 13

live in/on GI tract, resp tract, mucous membrane, skin, ears,

• not normally in blood, urine, lymph, CSF
• usually beneficial, inhibit the growth of pathogens

Question 14

how does normal flora inhibit the growth of pathogens?

Answer 14

• secrete antimicrobial toxins that alter pH
• compete for nutrients and space
• stimulate immune defense

Question 15

pathogenic bacteria?

Answer 15

<3% of species, must invade tissue and establish

-host must be susceptible

Question 16

pathogenicity?

Answer 16

ability to enter host and cause disease (involves complex interactions between pathogen and host)

Question 17

opportunistic pathogens?

Answer 17

non-pathogen becomes pathogen
-normal micro become harmful if opportunity arises like immunosuppression, disturbances in normal flora, barrier damage, organism in unusual location)

Question 18

pathogen factors? (of bacteria)

Answer 18

• virulence (how likely to cause disease)
• invasiveness (secretes chemicals that allow invasion/ adhesion)
• toxins (endotoxins and exotoxins)

Question 19

host factors? (of bacteria)

Answer 19

• compromised immune system
• malnutrition
• invasive procedure/injury/stress
• other infections

Question 20

reservoirs of infection (where pathogens hide and live)?

Answer 20

-humans, animals, plants, soil, food, water, fomites (inanimate surfaces)

Question 21

modes of transmission (for bacteria)?

Answer 21

• direct contact (skin, body fluids, transfusion)
• airborne (resp. droplets)
• contamination (water, food, fomites)
• animal contact (bites, feces)

Question 22

different kinds of toxins? (endo, exo)

Answer 22

• endotoxins: released when cell lyses or dies

- exotoxins: secreted by cell

Question 23

antibiotics are?

Answer 23

antimicrobiolagents used in treatment and prevention of bacterial infections

Question 24

what is an ideal antibiotic?

Answer 24

highly toxic to pathogen

Question 25

broad vs. narrow spectrum antibiotic?

Answer 25

broad spectrum= wide range of bacteria | narrow spectrum= specific families of bacteria

Question 26

favourable pharmacodynamics and antibiotics?

Answer 26

not toxic to host, does not interfere, no side effects

Question 27

favourable pharmacokinetics and antibiotics?

Answer 27

absorption, distribution, metabolism, excretion

Question 28

modes of action for bacteria?

Answer 28

- inhibit cell wall synthesis - inhibit protein synthesis - disrupt cell membrane - inhibit bacterial enzymes - inhibit DNA/RNA synthesis

Question 29

chemical control of bacteria?

Answer 29

antiseptics and disinfections= chemical agents that destroy bacteria or inhibit growth of bacteria when applied to surfaces

Question 30

antiseptic is applied to?

Answer 30

body surface

Question 31

disinfectant is applied to?

Answer 31

surface of objects

Question 32

viruses are?

Answer 32

extremely small, not cellular (protein capsule surrounded by genetic material)

Question 33

obligate intracellular parasite and viruses?

Answer 33

cannot reproduce without host cell (virus infects the host cell, host cell makes viral proteins) -CANNOT produce energy (depends on host cell)

Question 34

structure of viruses?

Answer 34

- genetic material (dna or rna) - protein coat= capsid that encloses genetic material - viral spikes on surface recognize and bind specific receptors on the host cell membrane - geometric/symmetrical shapes are common

Question 35

host specificity and viruses?

Answer 35

viruses are very host specific (viral spikes)

Question 36

hepatitis..

Answer 36

binds human hepatocytes---- HIV--- human CD4 T cells

Question 37

norovirus...

Answer 37

binds epithelial cells lining intestine--- rhinovirus---- lining upper resp

Question 38

lifecycles (of a eukaryotic virus)

Answer 38

1. virus enters cells (viral spikes used to recognize host) 2. host cell synthesizes viral DNA and makes viral RNA (transcription) 3. host makes viral proteins ("translation") 4. host cell assembles viruses 5. viruses acquire a glycoprotein envelope as they escape through the cell membrane - -- new virus!

Question 39

what are the two types of viral life cycles?

Answer 39

1. lytic lifecycle | 2. lysogenic lifecycle

Question 40

lytic cycle "virulent"?

Answer 40

- viruses are assembled by host cell | - viruses cause host cell lysis when they escape

Question 41

lysogenic cycle "temperate"?

Answer 41

- viral DNA incorporated into host genome - host replicates DNA as it divides - virus may remain latent (dominant) for years but can potentially enter lytic life cycle

Question 42

oncogenic viruses?

Answer 42

cancer causing; insertion of viral DNA into host - genome may trigger transformation if genes that regulate cell division or growth (proto-oncogenes) are affected - normal cell--- transformed---> cancerous cell

Question 43

are antibiotics effective for viruses?

Answer 43

no, challenging to control, viruses hide in host cell

Question 44

most effective control for viruses?

Answer 44

vaccination (mobilizes immune defence mechanisms to prevent illness!)

Question 45

fungi diseases are called?

Answer 45

mycoses

Question 46

fungi infections are often?

Answer 46

opportunistic (normal flora disturbed and fungi proliferate) normal flora ---- imbalance----opportunistic species have been isolated by fungi

Question 47

examples of fungi?

Answer 47

athletes foot, ringworm, candida, lung infections

Question 48

protozoas are?

Answer 48

most are non-pathogenic, some single celled eukaryotes are parasites that cause disease

Question 49

route of infection for protozoas?

Answer 49

oral ingestion or transmission by animals | -malaria, toxoplasmosis, schistosmosis, giardia

Question 50

metazoan is?

Answer 50

eukaryotic, some multicellular parasites cause disease - roundworms, tapeworms, flukes - internal parasites= endoparasites - oral route of infection