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What is a Bioassay?

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What is a Bioassay? Bioassay A bioassay involves the use of biological organism to test for chemical toxicity. Used by the FDA Bioassays are used to test drugs and ... – PowerPoint PPT presentation

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Title: What is a Bioassay?


1
What is a Bioassay?
2
Bioassay
  • A bioassay involves the use of biological
    organism to test for chemical toxicity.

Canaries are used by coal miners as a way to test
for high levels of methane (an odorless gas)
3
Used by the FDA
  • Bioassays are used to test drugs and skin care
    products before being okayed by the FDA.

4
QoD In Science Notebooks
  • 1. What is a bioassay? Use complete sentences.
  • 2. What do we always wear for safety in the
    laboratory?

5
BIOASSAYS
  • Dose/Response Bioassays are used to
  • Estimate toxicity to humans and other organisms.
  • Estimate maximum concentrations of specific
    chemicals allowed to discharge into bodies of
    water.
  • Investigate hazardous waste sites.

6
Bioassay Species
  • 3 organisms are often used
  • Daphnia
  • Duckweed
  • Lettuce Seeds
  • Expose organisms to chemicals and measure how
    they respond.

7
Bioassay Species
  • Lettuce Seeds
  • In Petri dishes with test samples
  • After 5 day check for
  • germination (sprouting)
  • radicle length (length of the sprout)

8
CONCENTRATION VS. DOSE
  • LD50 the Dose that is Lethal for 50 of the test
    organisms.
  • Used for Daphnia
  • TC50 the Concentration that causes a 50 drop in
    growth or health of the test organisms (Toxic
    Concentration).
  • Used for seeds (they may not die, just not
    sprout)

9
An Introduction To Experimental Design
  • The Manipulated Variable in an experiment
    represents the factor that you vary while keeping
    everything else constant.

10
An Introduction To Experimental Design
  • The Responding Variable (Dependent Variable) in
    an experiment represents what we measure (what we
    expect to vary depending on the manipulated
    variable).

10
Radicle Length
11
An Introduction To Experimental Design
  • The control is the untreated group, used for
    comparison with the treatment groups.

12
An Introduction To Experimental Design
  • Replicates (trials) are groups of organisms
    exposed to identical conditions.
  • The more replicates the better.

13
Safety
  • Always wear your gloves and glasses
  • No eating or drinking
  • No horseplay!
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