Lab Exam 1 Study Guide
The lab exam will be half short answer questions, half practical questions. It will be
worth a total of 50 points. The practical questions will consist of examples of lab cultures
we grew and observed in our lab exercises as well as microscope usage. You will be
asked to look at them and answer two or three questions based on each culture or
specimen. Below are the general concepts I want you to focus on. It is up to you to know
what these are. Bold terms are especially important.
Ex. 2-1
Understand the concepts behind growing bacteria in lab: inoculation with a swab, TSA
media, incubation temperature, and incubation time. Colonies represent a cell (or
cluster of cells) that you put on the plate and that have grown up to a visible amount
Ex. 1-3
Know the differences between TSA slants and TSB (broth). Understand the steps you
took with aseptic technique. Know these terms: Bunsen burner, loop, needle, vortexer,
slant, broth
Ex. 1-4
Understand the purpose of doing a streak plate (isolation of colonies). Understand the
steps you do during a streak plate: 4 quadrants, flaming between each quadrant streak.
Ex. 2-2
Be able to use these terms to describe whole colony shape: round, irregular,
filamentous, lobate.
Be able to use these terms to describe colony height: convex, umbonate, flat, raised.
Be able to use these terms to describe colony texture: moist, dry, mucoid.
Be able to use these terms to describe colony color: opaque, translucent, shiny, dull.
Ex. 2-3
Be able to use these terms to describe slant morphology: filiform, friable, spreading
edge.
Be able to use these terms to describe slant color: opaque, translucent, shiny, dull.
Ex. 2-4
Be able to use these terms to describe liquid morphology: pellicle, sediment, uniform
fine turbidity, flocculent.
Ex. 2-7
Understand that this media contains thioglycollate which removes oxygen from the
media, but there is still oxygen near the surface. Remember how you inoculated this
media.
Be able to recognize growth patterns for these types of organisms: facultative anaerobe,
obligate anaerobe, obligate aerobe, microaerophile.
Ex. 7-3
Understand the technique involving dilution, spread inoculation, and placing antibiotic
disks onto the plate. Know how to measure a zone of inhibition and determine
susceptibility/resistance to the drug using the provided chart.
Disinfectants
Similar to Ex. 7-3, understand plating technique and measuring zones of inhibition.
Ex. 2-9
Understand straight line inoculation method used. Based on growth patterns, be able to
use these terms to describe an organism: psychrophile, mesophile, thermophile.
Ex. 2-11
Understand osmosis and how these plates put the cells in isotonic or hypertonic
conditions. Recognize growth patterns of halophiles.
Ex. 3-5
Understand the steps required to produce smears from a slant (plate) and broth.
Understand heat-fixing. Understand the steps in a simple stain. Know how to recognize
bacterial shapes (bacillus, coccus) and arrangements (single, diplo, staphylo, strepto)
Ex. 3-1
You will need to understand parts and functions of the microscope and how to properly
use a microscope. Review my Bio201 website if you need to.
Know how to: view specimens from lowest power to highest power, use oil immersion,
calculate total magnification, properly clean and put away a microscope.
Be able to identify these parts and know their functions: on/off switch, light intensity
knob (dimmer), ocular lens, arm, revolving nosepiece (turret), objective lenses,
stage, mechanical stage, mechanical stage adjustment knobs, iris diaphragm,
condenser, lamp, base, course focus knob, and fine focus knob.
Ex. 3-7
Understand the steps in the Gram Stain. Know the purposes of the primary stain,
mordant, decolorizer, and counterstain. Know what each stain is used for: Crystal
violet, iodine, ethanol, safranin. Know how the cell would look at each step.
Good luck!