DNA Objective: To learn the structure and function of DNA

Types of DNA _____________ DNA Found in the ___________ _____________ DNA (mtDNA) Only inherited from the __________________ side Nuclear DNA nucleus Mitochondrial Mitochondria maternal

Who discovered the structure of DNA? Watson and Crick knew DNA was made up of nucletides X-ray diffraction Uncovered the basic structure of DNA James Watson and Francis Crick In 1953 were given credit

Sources of DNA Blood _________ Saliva Sperm ___________ Body tissue Teeth ____________ from urine Sperm Root of Hair Bones Epithelial cells

DNA Overview

DNA Overview DNA Hydrogen bonds, double helix, nucleotides, nitrogen bases, pentose sugar, phosphate, backbone, base compliment rule

Nitrogenous Bases Purines ________ ring system Pyrimidines __________ Guanine Pyrimidines _________ ring system Cytosine ___________ Double Adenine Single Thymine

Table Talk Erwin Chargaff measured the levels of the nitrogen bases found in DNA. What conclusions can you make from the chart below? DNA Source Adenine Thymine Guanine Cytosine Calf Thymus 1.7 1.6 1.2 1.0 Beef Spleen 1.5 1.3 Yeast 1.8 1.9 Bacillus 1.1 2.6 2.4

Complimentary DNA Strands ACCCTTACT GTAGTGAG TTCCGGCCT AAACTAT

DNA Replication Map Helicase breaks hydrogen bonds Helicase separates strands Polymerase adds base compliments to free bases Hydrogen bonds form The original strands are used to make new copies. Results in two identical strands Why is this referred to as semi conservative replication?

Replication Example A G T C T A G C T A A T Helicase breaks hydrogen bonds A G T C Helicase separates strands Polymerase adds base compliments T A G C T A A T Results in two IDENTICAL strands

Semi-Conservative Replication Why is this considered semi-conservative replication? How does this prevent mutations?

Short Tandem Repeats (STRs) Polymerase Chain Reaction (PCR) DNA Typing Methods Short Tandem Repeats (STRs) Polymerase Chain Reaction (PCR) Short base sequence that is __________ in a DNA strand Less susceptible to ___________ Used to ________ the amount of DNA Primer is used to target a _______________ to be copied amplify repeated specific sequence STRs are usually found in stains on body or clothes degradation

Short Tandem Repeats

Results of PCR

Table Talk How does the structure of DNA allow it to make an exact copy of itself during replication? Can PCR be used on an entire strand of DNA? Why or why not? It can be, but there would be no point for doing it. DNA strands are HUGE! It would not make sense to make a copy of the whole strand, use an STR then do PCR.

Restriction Enzymes Cut DNA into __________ at a _______ base __________ fragments specific sequence

Restriction Enzyme Example #1 Base Sequence: A T A C G T A C C G T T A T G C A T G G C A Restriction Enzyme cuts at TAC Resulting fragments: How many fragments did you end up with?

Restriction Enzyme Example #2 Base Sequence: C G C A T T A C A T A G C G T A A T G T A T Restriction Enzyme cuts at CAT Resulting fragments: How many fragments did you end up with?

Restriction Enzyme Example #3 Base Sequence: A T T G A G C C G G A G T A A C T C G G C C T C Restriction Enzyme cuts at GAG Resulting fragments: How many fragments did you end up with?

Electrophoresis What does it do? _________ DNA Fragments Separates Determine if DNA fragments _______ Large fragments More _______ Small fragments ______ base pairs Separates match Larger fragments have more base pairs and do not move very far Small fragments have fewer base pairs and move further base pairs Fewer

Electrophoresis Firsts Lynda Mann and Dawn Ashworth Lynda Mann was abducted (in England), her body was found raped and murdered. Three years later a other woman was found raped and murdered in the same area. Richard Buckland confessed to the second murder only. Men from the local area were tested. Pitchfork convinced someone to give a sample for him, bragged about it and was caught. Colin Pitchfork First murder convicted by DNA (1987)

Continued 1987 1st time DNA profiling admitted as evidence Fingerprints left on victims window, Identified in a line up, same blood type that was found at the crime scene Convicted of raping 23 women Tommie Lee Andrews

Continued Acquitted of double murder DNA mishandled OJ Simpson Acquitted for the double murder of Nicole Brown and Ron Goldman His DNA mixed with the DNA of the victims was found in multiple locations Acquitted due to mishandling of DNA evidence OJ Simpson

Gel Electrophoresis http://www.youtube.com/watch?v=mN5IvS96wNk Simulation https://www.youtube.com/watch?v=b0f7hr3d3SI

Reading Gels Lanes Matching bands Fragments have the same # of __________ DNA fragments came from __________ Wells base pairs Bands same source

Table Talk Predict what would happen if you did not use restriction enzymes before you ran an electrophoresis gel?

What can you determine?

Identify . . . . .

Do any of the samples match?

The Footpath Murders https://www.youtube.com/watch?v=vjpR_Fx3_X8 https://www.youtube.com/watch?v=SJ6GtHxL6CI

Creating a DNA Fingerprint http://www.pbslearningmedia.org/resource/tdc02.sci.life.gen.sheppard/forensic-dna-analysis/ http://www.biology.arizona.edu/human_bio/problem_sets/dna_forensics_2/07c.html

RNA Structure Made up of __________ Is _________ stranded RNA nucleotide: _________ Phosphate nucleotides single Ribose sugar Nitrogen base

RNA Bases Adenine _________ Uracil Guanine _________ is replaced by Uracil Guanine Cytosine Thymine

RNA Molecule Use the following Key: Sugar = Green Phosphate = Orange Guanine = Blue Cytosine = Yellow Adenine = Red Uracil = Purple

Amino Acid Wheel

Protein Synthesis Also known as the Central _______ of Biology Dogma DNA is _________ then transcribed into mRNA mRNA is decoded into ____________ Forms a protein Dogma translated DNA is translated into a mRNA strand then the mRNA strand is decoded (using the wheel) into amino acids The amino acids are linked together to form a protein amino acid

Table Talk List two differences and two similarities between DNA and RNA. Predict what would happen if there was an error in either transcription or translation.