Lab Test 2

Question 1

Ways we reduce the number of bacteria found on loop

Answer 1

1. Flaming to kill carryover bacteria
2. Wiping loop on agar to remove bacteria

Question 2

Culture transfer experiment incubate at what temp?

Answer 2

37˚ (except serratia, 25˚)

Question 3

Reasons to use a plate

Answer 3

To isolate from mixed by spreading
To see discrete colony growth appearance
To see effect of chemicals/ radiation/ oxygen on growth

Question 4

Reasons to use broth

Answer 4

See pattern of dispersion
Grow large amounts for inoculating other media

Question 5

Reasons to use slant

Answer 5

To see growth pattern
To have surface growth in easy-to-handle tube

Question 6

Slant characteristics

Answer 6

Amount, color, shape, opacity, odor

Question 7

Amount slant

Answer 7

Small, moderate, large

Question 8

Shape slant

Answer 8

Filiform, echinulate, beaded, effuse, arborescent, rhizoid

Question 9

Opacity slant

Answer 9

Transparent, translucent, opaque

Question 10

Colony characteristics

Answer 10

Size, color, margin, shape, elevation

Question 11

Size colony

Answer 11

Pinpoint, small, moderate, large

Question 12

Margin colony

Answer 12

Entire, lobate, undulate, serrate, filamentous

Question 13

Shape colony

Answer 13

Circular, irregular, rhizoid

Question 14

Elevation colony

Answer 14

Flat, raised, convex, umbonate

Question 15

Broth characteristics

Answer 15

Turbidity, sediment, pellicle

Question 16

Sediment

Answer 16

Heavier than water accumulation

Question 17

Temp at which organisms function best is determined by

Answer 17

Proteins

Question 18

Temp below optimal

Answer 18

Slower growth, reversible when moved to warmer temp

Question 19

Temp increases

Answer 19

Rate of reaction increases

Question 20

Temp above optimal

Answer 20

Permanent denaturation of enzymes

Question 21

Psychrophiles

Answer 21

-5 - 19

Question 22

Mesophiles

Answer 22

Room temp: 17 - 30
Body temp: 30 - 42

Question 23

Thermophiles

Answer 23

40 - 78

Question 24

Extreme thermophiles

Answer 24

65 - 110

Question 25

Aerobes need oxygen for?

Answer 25

To catch electrons at the end of ETC (makes water) Makes 36 ATP per 1 glucose

Question 26

Anaerobes use what as final electron acceptor?

Answer 26

Pyruvate molecules from glycolysis Makes 2 ATP per 1 glucose Smelly

Question 27

Diff between antibiotics, antiseptics, and disinfectants?

Answer 27

All used to kill (bacteriocidal) or inhibit (bacteriostatic) bacteria Antibiotics: treatment of disease (ingest) Antiseptics: Safe to use on living tissue Disinfectants: Inanimate surfaces only

Question 28

How drugs work to kill/ inhibit bacteria

Answer 28

Cell wall interference Block protein synthesis Block metabolites Inhibit nucleic acid synthesis

Question 29

Broad spectrum drug

Answer 29

Show successful inhibition of gram + and gram - species

Question 30

Narrow spectrum drug

Answer 30

Affect only gram + or even only one species/ category of gram +

Question 31

Why are there multiple generations of drugs?

Answer 31

Modification of earlier drug for broader spectrum, lower toxicity, or avoidance of resistance factors

Question 32

Confluent growth of bacteria

Answer 32

Creation of a smooth film of growth on the surface of the agar

Question 33

UV radiation

Answer 33

Longer wavelength Low energy level - Does not penetrate Causes DNA damage (thymine dimers) Kills some, not all (repair enzymes, or beneath surface) - Sanitizes - Relatively safe to humans Cheaper

Question 34

Gamma Radiation

Answer 34

Short wavelength High energy - Penetrates Ionizes (dissociates) all molecules Dangerous/ lethal - Sterilizes Expensive

Question 35

Halophiles

Answer 35

Salt-lovers Pump water back in (energy needed - ATP) Raise solute levels within cytoplasm

Question 36

Transformation steps

Answer 36

Chilled competent Control - Y Experimental - X Add buffer to Y, add pAMP to X Chill on ice for 20 min 42˚ for 90 sec Chill on ice for 1 min 37˚ for 30 min Add 2 drops to plates

Question 37

What is transformation?

Answer 37

The absorption of small DNA fragments, and the use of these new genes

Question 38

Enriched

Answer 38

Extra nutrients for faster/ better growth

Question 39

Selective

Answer 39

Inhibitory of one group, while allowing growth of another to reduce time/ work/ money getting desired pathogen from mixed sample

Question 40

Differential

Answer 40

Allows bacteria to be grouped (biochemical characteristics) based on appearance on plate and to help identify unknown organisms faster/ cheaper

Question 41

PEA plate

Answer 41

Selective for hardy gram + cocci - Gram + tolerate alcohol best (hardy cocci only, so excludes gram + bacilli and gram + cocci like strep)

Question 42

Blood agar plate

Answer 42

Enriched (iron, protein in RBCs, dissolves nutrients in plasma) Differential for hemolysis (lyse RBCs?) Helpful to ID strep

Question 43

MSA plate

Answer 43

Selective for staph (tolerate salt (mainly staphylococci)) Differential for mannitol fermentation (mannitol only sugar present, pH indicator, facultatives ferment mannitol or not)

Question 44

EMB plate

Answer 44

Selective for gram - (dyes eosin and methylene blue inhibit gram +) Differential for lactose fermentation (lactose only sugar present, pH indicator, facultatives ferment lactose or not

Question 45

MAC plate

Answer 45

Selective for gram - (dye crystal violet and bile salts to inhibit gram +) Differential for lactose fermentation (lactose only sugar present, pH indicator, facultatives ferment lactose or not)

Question 46

Deep ocean muds

Answer 46

Microaerophiles