BI 234 LAB PRACTICAL EXAM QUESTIONS AND
ANSWERS WITH COMPLETE SOLUTIONS VERIFIED BY
EXPERT
Gram negative bacteria
Thin layer of peptidoglycan. Contains outer membrane (lipo-polysaccharides,
lipoproteins, phospholipids) with porin.
gram positive bacteria
Bacteria that have a thick peptido glycan cell wall, and no outer membrane. They stain
very darkly (purple) in Gram stain.
endospore stain
A differential stain used to detect the presence and location of spores in bacterial cells.
TSA plate
Tryptic Soy Agar
- universal growth medium
plate streaked for isolation
4 quadrants
Phenylethyl Alcohol Agar (PEA)
Selects for the growth of gram positive microorganisms, because Phenylethyl Alcohol is
inhibitory to the growth of gram negative organisms
, MacConkey Plate
selective medium-growth of gram -, gram + is inhibited
differential medium-fermentation of lactose causes growth
mannitol salt plate
selective medium-growth of halotolerant bacteria
differential medium-mannitol fermenters turns plate yellow
fluid thioglycollate
Slightly viscous broth used for determining the oxygen requirement of different microbes
Catalase Test
used to identify organisms that produce the enzyme catalase
indicator used in thioglycollate broth
Resazurin
color difference allows for confirmation of oxygen and no oxygen areas in the tube
biosafety level
Level (BSL 1-4) or Biosafety containment level describes the specific equipment,
practices and facilities that must be used for containment of biological agents
bsl-1
no special precautions; basic teaching labs
bsl-2
lab coat, gloves, eye protection
example of bsl2 bacteria
salmonela enterica, staphylococcus aureus and HIV
bsl-3
ANSWERS WITH COMPLETE SOLUTIONS VERIFIED BY
EXPERT
Gram negative bacteria
Thin layer of peptidoglycan. Contains outer membrane (lipo-polysaccharides,
lipoproteins, phospholipids) with porin.
gram positive bacteria
Bacteria that have a thick peptido glycan cell wall, and no outer membrane. They stain
very darkly (purple) in Gram stain.
endospore stain
A differential stain used to detect the presence and location of spores in bacterial cells.
TSA plate
Tryptic Soy Agar
- universal growth medium
plate streaked for isolation
4 quadrants
Phenylethyl Alcohol Agar (PEA)
Selects for the growth of gram positive microorganisms, because Phenylethyl Alcohol is
inhibitory to the growth of gram negative organisms
, MacConkey Plate
selective medium-growth of gram -, gram + is inhibited
differential medium-fermentation of lactose causes growth
mannitol salt plate
selective medium-growth of halotolerant bacteria
differential medium-mannitol fermenters turns plate yellow
fluid thioglycollate
Slightly viscous broth used for determining the oxygen requirement of different microbes
Catalase Test
used to identify organisms that produce the enzyme catalase
indicator used in thioglycollate broth
Resazurin
color difference allows for confirmation of oxygen and no oxygen areas in the tube
biosafety level
Level (BSL 1-4) or Biosafety containment level describes the specific equipment,
practices and facilities that must be used for containment of biological agents
bsl-1
no special precautions; basic teaching labs
bsl-2
lab coat, gloves, eye protection
example of bsl2 bacteria
salmonela enterica, staphylococcus aureus and HIV
bsl-3
