Do Now: 3/16Period 4: Science & Computers 3rd period today – get right to work!

Period 2:

Radiation levels in Tokyo are 20 times above background levels, with recent measurements about 10 μSv/day. Remember the 1% / 5 year

cancer threshold we talked about yesterday is 1 Sv.

1. The Tokyo Metropolitan Government has assured residents of Japan’s capital city that the area is still safe. Do you agree? Justify

your answer.

2. 100 mSv/hr is considered to be the level “dangerous to human health.” How many hours of exposure at this level will produce the

1% cancer effect?

Syllabus Update

• There is NO CHANGE to the assigned readings.• GEL ELECTROPHORESIS is now today’s topic,

because of our “breaking science news” day yesterday.

• GENOMICS / BIOINFORMATICS will no longer be a topic in class.

• There is NO CHANGE to the assigned readings.

GEL ELECTROPHORESIS

• WHAT IT IS: A method for separating DNA fragments based on their size.

• WHY IT’S USEFULL:– Isolating important sequences from others– Measuring & mapping DNA sequences– Identification (DNA fingerprinting)

• HOW IT WORKS: Different sized DNA molecules move through a gel at different speeds, causing them to separate.

Virtual Lab

• http://learn.genetics.utah.edu/content/labs/gel/

Short fragments of DNA move faster through gel

Gel Electrophoresis in Criminal

Investigations• Suspect & crime scene

DNA collected.• PCR with standard

primers• Cut samples with same

restriction enzyme• Separate DNA

fragments by gel electrophoresis.

DNA Paternity Testing

• Each fragment seen in child sample must come from mother or father.

• Which gel has the right father?

Plasmid Mapping Extra Credit

• You have been given gel electrophoresis data from the digestion of a fictitious plasmid, pOLY1, with several restriction enzymes.

• Each enzyme cuts the plasmid in one or two locations.

• Use the fragment sizes to make a map that shows how the restriction sites are arranged on the plasmid. Indicate the distance between sites in kbp.