modified Cells to organisms practical exam

• differentiates bacteria based on gram positive vs negative

• uses differential lysis

• weaker envelope of gram negative can be destroyed by _____, gram positive stays intact

• how to preform

  • flame loop

  • place a colony of bacterial isolate on microscope slide

  • place a drop of 3% _____ onto bacteria

  • mix bacteria with loop for 30-60s

  • observe consistency of bacteria as pull loop away

    • if mix gets viscous and stringy, organism is likely gram negative if not likely gram positive

potassium hydroxide test

• tests for the presence of cytochrome C ______

• tests if the bacterium can use oxygen for energy via the electron transport chain

• uses N,N, N’, N’- tetramethyl-p-phenylenediamine (TMPD) as a redox indicator

• blue → ______ positive (obli. o2 or fac ano2)

• colorless → ______ negative (obli. ano2)

oxidase production test

• tests if bacteria can grow in the presence of oxygen

• uses a pH indicator to show when bacteria have acidified in the media

• how to preform

  • two test tubes inoculated with bacteria

  • one subsequently sealed w/ paraffin

• yellow→ positive

• purple→ negative

• if both tubes are yellow → fac anO2

• if only non sealed tube is yellow → obli O2

• if only sealed tube is yellow → obli anO2

• genera of gram negative, rod shaped

oxidase-fermentative test

• tests if bacteria possess ________

• H2O2 is made as an end product of aerobic breakdown of sugars

• H2O2 is toxic to bacteria if it accumulates

• bacteria produce ________ to convert H2O2 to water and O2

• how to test:

  • colony on microscope slide

  • place a drop of 3% H2O2 onto slide

  • Mix and see if bubbles form

• Bubbles appear → ________ positive (obli O2 or fac anO2)

• No bubbles → ________ negative (obli anO2)

• differentiation of gram positive

catalase production

volume of air breathed in and out without conscious effort

tidal volume

additional volume of air that can be inhaled with maximum effort after a normal inspiration

inspiratory respiratory volume

additional volume of air that can be forcibly exhaled after a normal expiration

expiratory respiratory volume

The total volume of air that can be exhaled after a maximum inhalation

vital capacity

volume of air remaining in the lungs after maximum exhalation

residual volume

VC =

TV + IRV + ERV

TLC =

RV + VC