Labs Revision

Question 1

Microorganisms multiply themselves in a culture media

Answer 1

Cultivation

Question 2

Culture media contains

Answer 2

Water
Carbon source
Nitrogen source
Buffer
Mineral source

Question 3

Culture media acc to purpose

Answer 3

Slant»storage of culture
Deep»gas requirements/motility
Plate»pure isolations/ observe biochemical reactions

Question 4

Culture media acc to nutritional components

Answer 4

Defined
Complex
Synthetic

Question 5

Acc to physical state

Answer 5

Liquid/ semi solid/ solid

Question 6

Acc to application

Answer 6

General purpose
Enriched> blood agar
Slective
Differential> MacConkey

Question 7

Isolation techniques

Answer 7

Streaking
Pour plate
Spread plate

Question 8

Determining microbial count

Answer 8

Turbidity
Plate count

Question 9

Calculating CFU

Answer 9

No.of colonies*dilution/ volume

Question 10

Colony identification

Answer 10

Shape/texture/height/color/consistency

Question 11

Microscopic identification

Answer 11

Simple stain
Gram stain
Acid fast
Special(endospore)

Question 12

Why stain

Answer 12

To differentiate microorganisms from their environment
Detailed observation
Different type differentiation

Question 13

Simple vs differential staining

Answer 13

1 solution to fixed smear- visualise morphology
Several reagents- distinguish cellular somponenets

Question 14

Smear preparation

Answer 14

Thin white film

Question 15

Fixation types

Answer 15

Heat»passing slide on bunsen burner to prevent discarding of smear while staining
Methanol&raquo_space;better than heat , prevents liquid specimens from washing off, clearer bg

Question 16

Stain types

Answer 16

Simple» positive(organism stained)/ negative(background stained)
Differential»gram staining(peptidoglycan)/ acid fast(wax like cell wall)
Special&raquo_space;endospore
Capsule staining»

Question 17

Gram staining

Answer 17

Gram +ve purple
Gram -ve pink/ red
Fixation - Crystal violet 30 sec (primary stain) - iodine 60 sec (mordant) - alcohol 10 sec (decolouriser& dehydrate peptidoglycan )- counter 1 mins stain(safranin)

Question 18

Acid fast

Answer 18

Carbol fuchsin
Steam(loosen waxy layer to let stain in)
Decolouriser
Methylene blue
Acid fast> red
Non> blue

Question 19

Why are spores resistant
Dyed with

Answer 19

High calcium and dipicolinic acid
Malachite green+ steam+safranin

Question 20

Capsule staining
Why difficult

Answer 20

Capsules are water soluble , maybe removed with vigorous washing
Non ionic so dyes will not adhere to it

Question 21

Physiological tests

Answer 21

Fermentation (MacConkey agar / Mannitol salt agar/ phenol red broth)
Hydrolysed products test (urease test/ catalase test)

Question 22

Macconkey agar
Results

Answer 22

Gram -ve and lactose fermenting
Bile salts that inhibit gram +ve
Crystal violet
If not lactose then peptone
E.coli-klebisiella
Ph gets low red/pink colonies(lactose fermenting)

Question 23

Mannitol salt agar

Answer 23

Phenol red
Selective for staphylococcus due to salt conc. NaCl
Ph gets low, yellow colour and or growth

Question 24

Phenol red brith

Answer 24

Carbohydrate fermenter
Phenol red
Gas trapped in durham tube and or yellow colour

Question 25

Urease

Answer 25

Urease enzyme
Phenol red
Red, bright colour

Question 26

Catalase

Answer 26

Catalase enzyme production
Bubbles

Question 27

Dimorphic appearance is important for
Change acc to

Answer 27

Infectivity and surviving diverse environments
Temp/nutrients
25 mold
37 yeast

Question 28

Dimorphic fungi examples

Answer 28

Histoplasma capsulatum»lung disease histoplasmosis
Candida albicans>vaginal yeast infections, oral thrush,candidiasis of skin

Question 29

Culturing of fungi

Answer 29

Bacterial media>negative,less effective
Fungal media> sabouraud dextrose agar/mycobiotic/germ tube test/urease test

Question 30

Conidia names acc to size

Answer 30

Macroconidia
Microconidia

Question 31

Inappropriate usage of antibiotics leads to

Answer 31

Increased levels of antibiotic resistance by exerting selective pressure

Question 32

Antimicrobial tests

Answer 32

Dilution tests»min conc of antibiotic to control infection

Broth dilution method»micro (96 well)or macro (2ml)dilution,2 fold dilutions in liquid growth medium

Agar dilution method»different conc of antimicrobial into agar 2 fold then inoculation

Disk diffusion»kirby bauer,MHA plate, disk with antimicrobial on agar

Question 33

MIC

Answer 33

Minimum inhibition conc
Lowest conc of antimicrobial that inhibits bacterial growth

Question 34

Bacterial suspension should be equivalent to….. this is done by matching that turbidity

Answer 34

0.5 McFarland standards

Question 35

Growth medium that is commonly used for antibiotic suspectability tests and allows for even diffusion of the antibiotic

Answer 35

Mueller hinton plate
MH

Question 36

Algae are

Answer 36

Protist
Uni or multicellular

Question 37

Cell walls of algae…
They are

Answer 37

Cellulose
Photosynthetic

Question 38

Classification of algae
Brown

Answer 38

Brown&raquo_space;multi/known as kelps which are long and tough/non motile/ reproductive cells have 2 flagella/cooler marine water/focus/macrocytsis/ have fucoxanthin

Question 39

Red algae

Answer 39

Red»multi/made of threads forming flat sheets/ non motile
Attached to rocks
Phycoerthrin
Some ansorb calcium carbonate to their cell walls
Chondrus
Polysiphonia

Question 40

Antibiotics

Answer 40

Zithromycin, nystatin, ciprofloxacin

Question 41

Green algae

Answer 41

Uni or multi
Colonial
Have flagella
Chlorella/chlamydomonas