Characteristics Of Microorganisms

Question 1

Commensal organism

Answer 1

• specific locations of human body

- prevent disease

Question 2

Pathogen

Answer 2

• cause damage to human tissue

- infection and disease (result)

Question 3

Microorganism

Answer 3

• cannot be seen w/ unaided eye

- often unicellular

Question 4

Prokaryotic cell

Answer 4

• lack true membrane enclosed nucleus

- genetic material in a nucleoid (single circular chromosome)

Question 5

Eukaryotic cell

Answer 5

• true membrane bound nucleus (several chromosomes)

- fungi and animals

Question 6

Four major classes of microorganisms

Answer 6

1. Protozoa
2. Fungi
3. Bacteria
4. Viruses

Question 7

Cytoplasmic membrane

Answer 7

• separates cytoplasm from cell wall

- LIPOPROTEIN

Question 8

Function: Cytoplasmic Membrane

Answer 8

• site of electron transport system
• regulates osmotic pressure in cell (diffusion or active transport, waste out of cell)
• repsonsible for detection of environmental cues for chemotaxis

Question 9

Cell wall

Answer 9

-found immediately outside of cell membrane

Aka murein layer or peptidogylcan layer

Question 10

Function: cell wall

Answer 10

• gives bacteria it’s shape
• murein layer has gel substance help secure nutrients from environment
• enzymes degrade macromolecules and detox substances enter through outer membrane

Question 11

Gram Positive

Answer 11

• thicker layer of peptidoglycan

- cw contains teichoic acid and lipoteichoic acid

Question 12

Gram Negative

Answer 12

• cw w/ 2 layers, innermost = thin peptidoglycan, outer = protein, lipopolysaccharide and phospholipid
• periplasmic space (between internal surface of outer membrane and external surface of cellular membrane)

Question 13

100x

Answer 13

Oil immersion

stained slides

Question 14

40x

Answer 14

Wet mounts w/ coverslip

Question 15

10x

Answer 15

Focus slide and count for cells

Question 16

Gram stain

Answer 16

1. Crystal violet (primary stain)
2. Iodine (mordant)
3. Acetone-Alcohol (decolorizer)
4. Safranin (secondary stain)

Question 17

Lag phase

Answer 17

Cells adjust to environment

Question 18

Log phase

Answer 18

Exponential growth

*testing done here

Question 19

Stationary phase

Answer 19

No increase in growth

Question 20

Death

Answer 20

Cessation of growth

Question 21

Media - forms?

Answer 21

• solid
• semi solid
• liquid

Question 22

Simple media

Answer 22

• basic media

- non fastidious

Question 23

Enriched media

Answer 23

Basic media + extra nutrients

Question 24

Differential media

Answer 24

Basic media + differentiating substance (pH + sugar)

Question 25

Selective media

Answer 25

Basic media + selective substances (increased salt content)

Question 26

Enrichment media

Answer 26

Basic LIQUID media + additional substance specific for one organism

Question 27

Media QC

Answer 27

• sterile
• stable
• reasonable shelf life
• clear and/or proper colour, consistency, depth, no hemolysis

Question 28

Strict aerobes

Answer 28

Cannot grow in absence of O2

Question 29

Facultative anaerobes

Answer 29

can grow aerobically or ANO2

Question 30

Capnophilic

Answer 30

need increased CO2 (candle jar or incubator): 5-10 % CO2

Question 31

Microaerophilic

Answer 31

need low levels of O2 (jar with pack)

Question 32

Strict anaerobes

Answer 32

cannot grow in the presence of O2 (jar with pack=different pack!)

Question 33

Media examination

Answer 33

• relative size
• pigmentation
• hemolytic reaction
• texture
• opacity

Question 34

Alpha hem.

Answer 34

Green

Question 35

Beta hem.

Answer 35

Clear

Question 36

Gamma hem.

Answer 36

No change

Question 37

Biochemical tests

Answer 37

• manual (individual tubes, manual interpretation
• API
• automated (Vitek, AST)

Question 38

Serological tests

Answer 38

Confirmatory, or epidemiology purpose

Question 39

Maldi-tof

Answer 39

Clinical labs
Results in minutes
Organism can be dead
Minimal cost