Microbiology review

Question 1

Bacteria is…

Answer 1

prokaryotic
Small, primative & simple. They lack membrane bound organelles (have no nucleus, golgi, ER, mitochondria, or vacuoles)
2-10 uM

Question 2

fungi & protozoa are…

Answer 2

eukaryotic

Question 3

viruses are…

Answer 3

non-cellular

Question 4

how may microorganisms are pathogenic

Answer 4

less than 3%

Question 5

Explain the binomial nomenclatures system

Answer 5

first work = genus

second word = species

Question 6

how are bacteria classified

Answer 6

• O2 requirements
• metabolism
• differential staining
• motility
• pathogenicity
• morphology
• *Mostly done with DNA sequence these days

Question 7

how to describe bacteria shape

Answer 7

grouping-shape

Question 8

bacterial cell structure:

Answer 8

• Circular DNA
• abundent ribosomes
• cell envelope = membrane & cell wall
• gelatinous capsule
• flagella for locomotion
• pilli for attachment/ transfer of genetic material

Question 9

Gram +

Answer 9

thick peptidoglycan then protein cell membrane

Question 10

Gram -

Answer 10

lipopolysaccharide then peptidoglycan

Question 11

explain bacteria growth

Answer 11

binary fission (mitosis/identical cells)
ca double every 1-24hr 
-some are highly resistant endospores

Question 12

Bacteria are the…

Answer 12

most numerous & pervasive oragamism (ubiquitous)

Question 13

Normal flora

Answer 13

life on/in GI tract, resp, mucous membranes, skin, ears
NOT NORMALLY in the blood, urine, lymph, CSF
-they inhibit pathogens
-secrete antimicrobial toxins that alter ph
-compete for nutrients /space
-stimulate immune defense

Question 14

What is pathogenicity

Answer 14

ability to enter host & cause disease

these are complex interactions between pathogen & host

Question 15

what is opportunistic pathogens

Answer 15

normal microbiota become harmful if poortunity rises such as immunosuppression, disturbances in flora, barrier damage, organisms in unusual locations

Question 16

what are pathogenic factors

Answer 16

1) Virulence (how likely to cause disease)
2) Invasiveness (chemicals that allow invasion/adhesion)
3) Toxins (Endotoxins released when cell lyses or dies) (exotoxins secreted by cells)

Question 17

what are host factors

Answer 17

1) compromised immune system
2) malnutrition
3) invasive procedure, injury, stress
4) other infections

Question 18

What are reservoirs of infection

Answer 18

human, animal, plant, soil, food, water, fomites (inanimate surfaces)

Question 19

What are the modes of transmission

Answer 19

Direct contact - fluid/skin
Airborn - Respiratory droplets
Contamination- water, food, fomites
animal contact

Question 20

what is a bactericide

Answer 20

it destroys bacteria

Question 21

what is bacteriostatic

Answer 21

inhibit growth of bacteria (not sterile)

Question 22

what is antiseptic

Answer 22

applied to body surface

Question 23

what is disinfectant

Answer 23

applied to surface of objects (not sterile)

Question 24

What are antibiotics

Answer 24

antimicrobial agents used in treatment & prevention of bacterial infections

Question 25

What are ideal antibiotics

Answer 25

Highly toxic to pathogen - favourable pharmodynamics (what the drug does to the body) - Favourable pharmokinetics (what the body does to the drug. eg. metabolism) - not likely to cause resistance

Question 26

what is antibiotic resistance

Answer 26

Bacteria are always reproducing by cloning. Sometimes there is mutation errors, causing abnormal bacteria to be produced & cloned further.These abnormal bacteria with the gene mutation sometimes prove to be a new resistant strain of bacteria. but since it's only a few among millions its ok. When antibiotics are used when they aren't needed they kill all the non-mutated bacteria & leave only the clones with mutations that allow the antibiotics to not work... so then these ones with mutation will continue to reproduce by cloning & now you only have the mutated resistant bacteria cloning & thriving while the susceptible bacteria has all died.

Question 27

what are some modes of antibiotic action

Answer 27

- inhibit cel wall synthesis - inhbit protein synthesis - distrupt cell membrane - inhibit bacterial enzymes - inhibitDNA/RNA synthesis

Question 28

explain viruses generally

Answer 28

very small (0.2-0.02 um) (much smaller than bacteria) not cellular (protein capsule surrounded by genetic material -OBLIGTE INTRACELLULAR PARASITE -can't reproduce w/o host -cannot produce eng..

Question 29

what is the structure of viruses

Answer 29

``` genetic material = DNA/RNA protein coat = capsid -some have protective envelope -no cell membrane or organelles -viral spikes recognize & buds to SPECIFIC receptors on host cell membrane -geometric/symetrical shape ```

Question 30

what is viral host specificity

Answer 30

The viral spikes recognize specific receptors on specific host cells - Hepatitis -> hepatocyes - HIV -> T cells - norovirus -> epithelial cells of intestine - Rhinovirus -> lining of upper resp tract

Question 31

explain the general virus life cycle

Answer 31

1) viral spike recognizes host cell 2) virus enters cell 3) host cell makes viral RNA "transcription" 4) host synthesizes viral DNA 5) Host cell assembles virus 6) aquire a glycoprotein envelope as they exit 7) new virus

Question 32

explain the LYTIC CYCLE

Answer 32

"Virulent" ex. Cold sore - viruses assembled by host cell - cause host cell lysis when they escape - may be triggered by: Stress, decreased immune system, infection or tissue damage, environmental risk factors (heat, cold, UV light)

Question 33

explain the LYSOGENIC CYCLE

Answer 33

"temperate" | - viral DNA incorporated into host genome - host replicate viral DNA as it divides ex. Chickenpox/shingles

Question 34

what is an oncogenic virus

Answer 34

cancer coughing -insertion of viral DNA into host genome may trigger transformation if genes that regulate cell division or growth (proton-oncogenes) are affected -ex. Epstein barr virus -> burkitts lymphoma papilloma virus -> cerival cancer hepatitis b -> liver cancer

Question 35

How do you control viruses

Answer 35

- ANTIBIOTICS DONT WORK - antiviral agents are often toxic to host - most disrupt viral life - most effective control of viruses is achieved by vaccination

Question 36

what is mycoses

Answer 36

disease caused by fungi

Question 37

characteristics of fungi

Answer 37

often opportunitistic, can be caused by use of antibiotics where normal flora are disturbed. many antibiotics are made from fungi (Athletes foot, ring work, candida, lung infection)

Question 38

characteristics of protozoa

Answer 38

- most are non-pathogenic but some single celled eukaryotes are parasites - route of infection by oral ingestion or transmission by animals (eg. Malaria, toxoplasmosis, schistosomiasis, giardia)

Question 39

characteristics of metazoan

Answer 39

some muilticelular parasites cause disease | round works, tapeworms, flukes