microbio lab midterm

what is included in purpose

the goal of the exercise, needs to be in past tense

what is included in methods

cite the lab manual, add info not in lab manual like cultures used, incubation times, in past tense and third person

what is included in results

only contain info on what you observe like color, size, texture, can add figures and tables, intext reference to tables and figures

what is included in discussion

contain interpretation of results, can include hypothesis and predictions

figure captions go where

at the bottom of figure

table captions go where

at the top of table

what do microorganisms need to survive 

macronutrients, micronutrients, water, environmental conditions 

macronutrients

nutrients needed in large quantities like carbs and proteins, oxygen

micronutrients

nutrients needed in small quantities like iron or zinc

medium

a sterile base that has all nutrients needed for microbial culture of cells to grow

broth

media that is liquid

plate, slant or deep 

media is semisolid with agarose powder 

common all purpose media

nutrient agar and trypticase soy agar or broth

sterile loop used when

inoculation of bacteria on or in medium for liquid cultures

sterile needle used when

inoculation of bacteria in medium from solid cultures

aseptic technique

sterilizing loop, culture transfer is done in convection current

parent culture 

the culture that you start with 

subculture

the culture you create

predictions

ideas of what culture will look like next week, need two descriptor words

incubation 

cultures incubated at 37 or 25 degrees celsius for 24 to 48 hours

Quadrant Streak Plate

to separate mixture of cells on agar surface, each parent cell reproduce to form a colony

quadrant streak technique

use aseptic technique, loop goes into test tube only once, sterilize loop after inoculating each sector

successful quadrant streak plate

have fewer colonies than preceding ones, find isolated colonies of the unknown

colonies

visible masses of growth that represent division of one parent cell or colony forming unit

how to evaluate colony growth 

observe characteristics like pigment, edge and elevation of colonies 

contamination

the presence of different colony types

what are causes of unsuccessful quadrant streak plates

forgetting to sterilize loop between quadrants, crossing over to quadrants too much, damaging the agar surface

purpose of slant transfer

to create a subculture from parent culture aseptically

purpose of quadrant streak plate

isolate single colonies from mixed culture

purpose of preparation of culture medium 

to prepare a tsa slant 

bunsen burner

used to sterilize equipment and provide convection current in air near you

Pour plate method

used for finding the number of bacteria in water samples, serial dilutions of a sample are made and portions of dilution are poured onto suitable agar medium

reasonable number of colonies for pour plate method

30 to 300 colonies

more than 300 colonies

too numerous to count

antimicrobial agents 

chemicals that kill microorganisms or prevent growth of microorganisms 

aim of antimicrobial agents

block metabolism and prevent organism from making things needed for reproduction

thing not affected by antimicrobial agents

spores and viruses

germicides

agents that kill microorganisms

Static agents

inhibit growth of microorganisms

disinfectants 

used on surfaces and equipment but not biological tissue 

antiseptics

can be used on biological tissues

physical methods of microbial control

heat, refrigeration, uv light

chemical methods of microbial control

alcohols, enzymes, heavy metals, antibiotics

brightfield microscopy

used for stained or naturally pigmented samples

phase contrast microscopy

enhance the contrast in colorless samples