MCB LAB Post Lab Handout Flashcards
Purpose of OIL in OIO
and reason behind
Focus light rays towards the eyepiece/providing a medium of same refractive index as the cover glass.
the air and the cover glass have different
refractive indices.
Relationship between
WORKING DISTANCE & NUMERICAL APERTURE
Inversely
shorter WD, higher NA
Refractive index of
- air
- oil
1.00
1.25
Relationship between
Refractive Index & NUMERICAL APERTURE
Direct
Formula for AREA of FOV
π r^2
- get diameter of FOV by counting Stage Micro
- Divide by 2 to get r
4 Advantages of observing living organisms
- Observation of unaltered/undistorted characteristics of the organism like size and shape
- Cellular processes like growth and reproduction can be studied
- Motility can be observed
- Simple to prepare
1 Disadvantages of observing living organisms
The refractive index of the cell is almost similar to that of water, therefore, difficult to observe.
Asexual and Sexual Reproduction of Bacteria (1 each)
A: Fission
S: Conjugation
3 major characteristics of fungi
non-photosynthetic, eukaryotic, heterotrophic
Composition of Fungi cell wall
mostly chitin
3 shapes of fungi
unicellular, filamentous, mycelia
YEASTS vs MOLDS in terms of:
- unicellular / multicellular
- shape (2; 1)
- type of asexual repro (2; 3)
- type of sexual repro (1; 3)
Y: unicellular
: spherical/oval shaped
: budding (saccharomyces cerevisiae) or binary fission (Schizosaccharomyces octosporus)
: ascospore formation
M: multicellular
: filamentous
: fragmentation/fission/asexual spores
: gamete formation/conjugation/sexual spores
What do you call the filaments that are present in molds
hyphae
what do you call mass of hyphae
mycelium
2 types of hyphae base on function
Vegetative hypha - anchorage and nutrient absorption
Fertile/Reproductive Hypha - carries reproductive structures
2 types of hyphae based on presence and absence of SEPTUM
Septate - w/ crosswalks/septa along hypha
Aseptate - or COENOCYTIC (lacks septa)
3 major characteristics of PROTOZOA
MOSTLY unicellular, non-photosynthetic, heterotrophic
Do protozoa have cell wall
no
Are protozoa motile (3) or nonmotile (1)
Some are
can be motile by
1. Flagella (Giardia)
2. Cilia (Paramecium)
3. Pseudopodia (Amoeba)
non-motile (Plasmodium)
2 major characteristics of MICROALGAE
microscopic, photosynthetic
What type of organism are microalgae? (3)
- Unicellular (diatoms and CHLORELLA)
- Multicellular (Spirogyra)
- Colonial (Volvox)
Type of reproduction in algae in terms of:
-asexual (2)
-sexual (1)
-asexual: fragmentation, budding/fission
-sexual: conjugation
3 components of LACTOPHENOL
PHENOL - disinfectant that KILLS MOLDS
LACTIC ACID - maintains osmotic pressure around molds and clarifies hyphae
GLYCEROL - prevents dispersal of spores
Are microalgae motile or non-motile
can be both
Why are Gram+ blue/violet and Gram- are pink?
Yung CV-I complex retains in Gram+ due to its THICK peptidoglycan layer kaya di siya naaabot ng Alcohol and retains its colors
Yung Gram- thin naman ung PG layer nya. The alcohol washes away the CV-I Complex don so ang final color nya is based on the last stain, SAFRANIN.
Purpose of each gram stain
Crystal Violet - Primary Stain
Iodine - Mordant
Alcohol - Decolorizer
Safranin - Counterstain
EXAMPLES for GRAM + and GRAM -
2 each
GRAM +
- Bacillus megaterium
- Bacillus subtilis
GRAM -
- Escherichia coli
- Pseudomonas aeruginosa
7 REQUIREMENTS of a good culture medium in terms of BIOPHYSICAL FACTORS:
a. Sufficient moisture
b. Favorable pH
c. Buffer salts
d. Reducing substance(s)
e. Suitable oxygen level
f. Temperature
g. *Indicator dye – (may be added to detect specific substances produced by the organism)
5 REQUIREMENTS of a good culture medium in terms of BIOCHEMICAL FACTORS:
a. Carbon sources
b. Energy sources
c. Nitrogen sources
d. Growth Factors
e. Minerals
Notable changes in pH adjusted CWA (pH 4, 7, and 9) after sterilization:
pH 4 - solid (before) -> liquid (after)
- HIGH TEMPERATURE prevented lattice formation and destroyed interlinking agar molecules
pH 7 - green (before) -> yellow (after)
- HIGH TEMP promoted heat reactions which turned the medium acidic
pH 9: pink (before) -> brown (after)
- HIGH TEMP caramelized sugars
Effects of Sterilization to Culture Media (2)
- Disaccharides upon heating hydrolyze into their components sugar
- Lower pH of medium by 0.2-0.4 units (sugars turn to acid due to heat reactions w peptone)
3 reasons for controlling microorganisms
TO PREVENT:
1. transmission of disease and infection
2. contamination by or growth of undesirable microorganisms
3. deterioration and spoilage of materials by microorganisms
3 types of equipment used in MOIST HEAT
- temp and time (+days)
- definition
- what materials they sterilize
a. Pressure cooker or autoclave
- 121°C for 15 min
- uses heat in the form of saturated steam under pressure to attain temperature higher than 100°C
- high temperature, not high pressure, is responsible for death of microorganisms
b. Arnold Sterilizer (for fractional sterilization or tyndallization)
- intermittent sterilization at 100°C for 30 min for 3 consecutive days
- used to destroy spores which germinate during the incubation periods within three successive days
- used for media/chemicals which decompose at temperature higher than 100°C.
c. Serological Water Bath – use temperature lower than boiling point
Why is 0.05 N was used as an initial titrant and 1 N for final titrant?
LOW FOR INITIAL -> prevent drastic pH changes and prevent overrun
HIGH FOR ADJUSTMENT -> prevent dilution
BACTERIOSTAT vs BACTERIOCIDE
Bacteriostat – inhibits bacterial growth and metabolism
Bactericide – kills bacteria but not necessarily their endospore
3 EXAMPLES of disinfectants
- Phenol (Carbolic Acid)
- Ethanol
- Quaternary ammonium compound (QUATS or QUAC)
