John Hay
John Hay Biomedical
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Genetics of Disease (Medical Interventions)
Unit 2: Unit 2.1 Gene ExpressionMI 2.1Biotechnology Research and Experiments

Compute Fold Change

Use molecular-test evidence to compute fold change accurately.

Builds on (2 levels back)inferred · high confidence
  • Control logic: Molecular results need positive and negative controls.
  • Signal interpretation: Bands, colors, curves, and E-values must be compared to a rule.

Prerequisites are inferred: pending teacher review.

Re-learn the skill with worked practice and clear examples.

Use molecular-test evidence to compute fold change accurately.

Step 1: Learn the key
Read the control [blank], compare the sample signal to the [blank], and report the result with one [blank].
GeneControlTreatedFold
X62424/6 = 4
Y1055/10 = 0.5
Fold-change table
Step 2: Use the model
Read the figure, table, control, range, or protocol before choosing an answer.
Step 3: Name the limit
Say what the evidence can support and what it cannot prove yet.
Practice

Use the molecular figure/table. Which interpretation is best supported?

Reviewed
GeneControlTreatedFold
X62424/6 = 4
Y1055/10 = 0.5
Fold-change table
  1. A.The sample should be compared to the controls or cutoff before making a call
  2. B.The sample result can be guessed from the title
  3. C.Controls should be ignored
  4. D.Any color or band means the same thing
Show the worked solution ▾

Answer: A. The sample should be compared to the controls or cutoff before making a call

  1. Step 1: Use controls/cutoff: The figure/table gives the comparison needed.
  2. Step 2: Make a careful call: A molecular result needs comparison before interpretation.

Why it's right: Controls or cutoffs give the sample signal meaning.

Why the others miss:
  • B: Titles do not determine results.
  • C: Controls are required.
  • D: Different signals can mean different things.

Aligned to Biotechnology Research and Experiments · reading level ~grade 9

Where you'd see this
  • In Unit 2.1 Gene Expression, this skill turns class evidence into a result another person can check.
Careers that use this
Molecular Technologist: Uses compute fold change to make a decision from evidence without overclaiming.
Video library
Watch: Compute Fold Change
RPKM, FPKM and TPM, Clearly Explained!!!
StatQuest with Josh Starmer · ~10 min
Guided notes

Fill these in as you work through the lesson.

Big idea: Use molecular-test evidence to compute fold change accurately.
Key terms: write the meaning
  • Control (known check for a test):  
  • Signal (visible or measured output):  
  • Threshold (cutoff for making a call):  
  • Validity (whether the result can be trusted):  
The rule

Read the control  , compare the sample signal to the  , and report the result with one  .

Check yourself
  1. Did positive and negative controls work? 
  2. What signal did the unknown show? 
  3. Is the result inside the reliable range? 
Work one example

Use the molecular-test figure to practice compute fold change and write one valid result call.