DNA Fingerprinting & Gel Electrophoresis

Do Now:

DNA FingerprintingEveryone (except identical twins) has a

unique DNA sequence in their cells.A technique called DNA fingerprinting can be

used to identify people (or parents) using their DNA.

DNA fingerprinting is MUCH more accurate than traditional fingerprints

How DNA Fingerprinting WorksDNA is extracted from a sample (like when

you got DNA from strawberries)Special enzymes called restriction enzymes

are used to cut the DNA samples into pieces.The DNA pieces are then put through a

process called gel electrophoresis.

Gel electrophoresisGel

electrophoresis is used to separate pieces of DNA.

DNA molecules are separated by size.

Analyzing the ResultsThe gel

shown shows what happened when the same piece of DNA was cut up with 3 different enzymes.

StandardSizes

DNA fragment

RestrictionEnzymes

Solving Crimes: Rape investigationThe DNA from a rapist

can be collected from the victim for up to about 24 hours after the crime.

The DNA found can then be compared to the DNA of suspects.

Which suspect committed the crime?

DNA Fingerprint Paternity TestingDNA

fingerprinting (with gel electrophoresis) can be used to determine who the parents of an organism are.

Just like genes, DNA fragments are inherited from both parents

Final ThoughtsA DNA fingerprint is like a unique barcode

for every organism on Earth.

DNA fingerprinting can be used to solve crimes and determine who an individual’s genetic parents are.

DNA fingerprinting uses gel electrophoresis to separate different size pieces of DNA created by chopping up the original piece using special enzymes

mRNA ProcessingRemember the central dogma of molecular

biology:DNARNAProtein

In eukaryotes, there is one more little step in between RNA and protein.

After an mRNA is made by transcription, it must be processed before translation.

Introns & ExonsAn mRNA sequence has introns and exons

within it.

Before being used to make proteins, the introns must be removed.

Intron: A part of an mRNA molecule that must be removed before translation.

Exon: A part of an mRNA molecule that will be translated.

Get rid of those Introns!

Before introns are removed, an RNA molecule is called pre-mRNA

Only the exons make it to translation!

That’s it for Molecular GeneticsYour review guide is due tomorrow!

We will be playing Jeopardy tomorrow: your review guide will be the only notes you may use.

Use the remainder of the period (and tonight) to complete anything on the review guide you haven’t yet.