Molecular Genetics

In 1869 a researcher was

working with cells and studying the

nucleus.

He found the nucleus was filled with a white goo and it was acidic.

He called it Nucleic Acid

but had no idea what it did.

Nucleic Acids

DNA Deoxyribonucleic Acid

RNA Ribonucleic Acid

For the storage of genetic information

For the transfer of genetic information

It took 50 years to figure this out.

There are two types :

The chemical structure of DNA wasn’t figured out until the early 1950’s.

James Watson and Francis Crick are given credit for finding the shape and chemical structure of the molecule.

Their research assistant Rosalind Franklin who did much of the work, died of cancer at age 39

due to exposure to X-Rays while working on the shape of the molecule.

They won the Nobel Prize in 1960 , she was never mentioned for her research work.

Watson and Crick Rosalind Franklin

Commercial X-Ray Diffraction Machine

As the X-rays pass through the DNA molecule they are

deflected and produce a shadow on a

photographic plate that revels the actual shape

of the molecule.

High Definition 3D X-Ray Crystallography

Enzymes

DNA

DNAContains a genetic code that defines

everything about you.

It is the recipe for you.

DNA is a Polymer

It is made up of many small pieces

3,000,000,000 pieces !

The small pieces that make up DNA and RNA are

called Nucleotides

( 5 Carbon Sugar )

Not all nucleotide are alike.

There are four different ones in

DNA.

The phosphates and sugars stay the same but the bases change.

The four bases are:

A for Adenine

T for Thymine

C for Cytosine

G for Guanine

These four letters make up your genetic code: A T C G

PurinesDouble Ring

Pyrimidines Single Ring

These Nucleotides hook together in a long chain

These long chains connect together giving DNA its characteristic shape

The Double Helix

The Double Helix is actually two single spirals that are connected together by the bases

A connects to T C connects to G

When the DNA replicates ( makes a copy of itself ) the strands separate and

two new strands are made.

So the new molecule of DNA is half old and half

new.

Semi-conservative Replication

Old Strand

New Strands

This is a map of Chromosome #1, some of

the genes found on this chromosome have been

identified but many have not.

A Gene is just a series of bases that codes for one protein

One Gene = One Polypeptide

Polypeptide = Protein = Enzyme

Hs.304694 is a group of genes that work together found on chromosome #1

This is called an Operon

This Operon contains 1,014,565 bases

Human DNA contains about 30,000 Genes

Human Genome Project

Here is a small portion of the base sequence found in Operon #304694 only 4000 of the 1,014,565

1 agacctgacc ccttcatcgg ggctcaagag acctctctct ccaaatctcc atttgcctcc 61 tctggctaag ctggaaaatg cacactctgc cctgggtgtt tccatattat ccgcctgccc 121 ttcctcctgg gtgcctcccg tagccttagt aagggctctg ctttcctggg cccctagagc 181 tgagccatgc tttgccataa aggtgctccc ggcttgcaac caatgtgtct gcttgtgcat 241 ctgtctgtgg gtgtggtggg gagggagggg accaggtggg tactggcact ctggggtccg 301 gactttatgt ccatggaggc cccaattgac tcagttcaag ggtcactgag gctttgctga 361 tgtagggaga gggccagagg gaggctccac cccagccggg ctgagccagg gaacctggga 421 caaaggtcag gtggctgatt ccaggtagtg ttttggagct gggcagtcag tggctgggcg 481 gggacatatg cccaagagcc accatgaact cccaggggcc tccaggcagg ggccctccat 541 cccgtgagta gggtggggaa gatggtgggg ttgccacagt cagggaacca agggcccgcc 601 tctgggggcc ctgaaacctg cctgcaggac ctgggatctg gagagctgcc cgctggcccg 661 gaggatgggc acccatccaa tcttggctta ggaaaggggc tgcagagggg cgggtgaggg 721 gtggcgggga tgcagcccca ccctggccag tgcctcatct cctgcctccg cataggcacc 781 aagtctttca acatgatgtc cccgacgggc gacaactcgg agctactggc tgagattaag 841 gcaggcaaga gcctgaagcc gacgccccag agcaaggggc tgaccacagt gttctcaggc 901 atcgggcagc cggccttcca ggtaggcggg cccagcagga gcctgcgacc cggcttccct 961 ggccctaggc caccgggcgc tcagccccac cgcttctccc tgcagcccga ttcgccgctg 1021 ccttctgtgt cacctgcact gtcaccagtc cggagcccca caccgccagc tgcggggttt 1081 cagccgctgc tcaatggaag cttggttccc gtgccgccca ctactcctgc gccgggagtg 1141 cagctggacg tggaggctct catccccacg cacgatgagc agggccggcc catccccgag 1201 tggaagcgcc aggtgatggt gcgcaagatg cagctgaaga tgcaggagga ggaggagcag 1261 aggcggaagg tgggtggggc ggggtgccca gggagccctg gggtctgcat ctggatgcac 1321 agcccatccc ccacgccacc cccaacccca acctcgggac ctcccatttt ctttcttttt 1381 tttttttctt ttcttgagac agagtcttgc tctgtcgccc aggctggagt gcagtggtgc 1441 gatctcgact cactgcaacc ttcgcctccc aggttcaaat gattctcctg cctcagcctc 1501 ccaggtagct gggattacag gcgcctgcca ccacgcccag ctaatttttt tgtattttta 1561 ttagagacgg ggtttcacta tgttggccag agctgggatt acaggcatga accaccgtgc 1621 ccggccattt tctttaggga aagcagggtg gtacaaccct gtttggggct tgtcccagtc 1681 tccacacaca cccccaccag cttgtccttg gaagtgagac agcagccttt ctcagactct 1741 ccttcaccgg cccagcacct gggatctggt taaaaggcct gttcggattt aggaggtctg 1801 ggcggggctg aggctcgcat ttctagccag ctcctgggtg aggctgctga tgctgctggt 1861 ccaaggacca cactgagtag ccaagagggc tttggtctca gtcttaggga cctgggctcc 1921 attgctgtgc tgccgccttc cagctgccga tactgagcct catccagcct cagtttcctt 1981 ctctgtaagg tgggctgatc agcaccagct ggcaggatga gttgcctttt attcatccaa 2041 caactattcc ccaaatgcca tttattttta ttttttattt tttgagacag ggtctcactc 2101 tgttactgag gctggagtac agtggtgcga tctcgactca ctgcaacctc cacctcctgg 2161 gttcaagcga ttctcccgcc tcagcctccc gagtagctgg gactacaaat gcccgccaac 2221 aatgccctgc taatttttgt attcttagta gagatggggt ttcaccatgt tggccaggcc 2281 ggtctcgaac tcctggcctc aagtgatccg cctgcctcgg cctcccaaag tgctgggatt 2341 acaggcgtga gccaccacgc ctggcccccg agtgccattt atgtgcccca cacactgttg 2401 tagcctctgg agattcatgg tgaacatatc aaggcctgct ctaaggtggc tgcggacatg 2461 tgtgcgagtc accaagcaca caaaatgggg cagtgtgaga gagtgggtgg cagtggagag 2521 aagtacctgg gctgatgcaa cacagccagc tgcaatgggg aacgcagggg actggggcag 2581 ccctaaccgg ccaccttata cgtgggctgg ggggcgtgtt agggaaggag gaggtgatgt 2641 ctaaggtgac acttggaaga cgagtgaggg gtggccagga ggagagtggg ctgaagagcc 2701 gcaggtgaga cagagcagtc tggaagtgag agtggatgtg gccctgactg tcctggagga 2761 agggggtcgc tgagctggag agacctcagt gggggccagg ttaccaagac ctggccagag 2821 gcccagaaga gaacggactt tctcctggag cactggggag ccgggtgcgg ggagtgttaa 2881 gcagggaaga ggctgcttcc tatttgtatg tggggagtgg atcgcatagg gtcaagatga 2941 atcagggacc tctgtggagg cgatggcagg cccaggggga aaactggaca tcagaggtgg 3001 agaaaagtga gcaaatgaga atattacggt gcccagctgt ccagcaggac gaagggaggg 3061 gaagggtggg cagctcagtg gaagctgcag ctgcagcctc tttaagagcg gagtggcctc 3121 tgattctgca cagaaaacat tgagcacagg gagcgggaag gcttgggcca caggggagct 3181 ggagaagggg tcatgagtct gggaggagag gcctcaatag ccgccctcgg atgggttggg 3241 gagggccacc gcgcctctca gcttcaacgc ctttcgcaag ttccttgggt ggtgtaatga 3301 gcgaacaagc caggcatgga gaccccgtct gctggcctgt tcttgccgcc gcagcagcga 3361 ccagcgaccg gccgtgcccc acgccaccga ccaaagtgga cactgcccag agcctggagc 3421 ggcggctcag gccgaagcct caccccagcg tcaccccccg ccggccagac gcggtccctc 3481 cctgcagacg cagccccgcg gagccattac accacccggg acatgcaaaa ggctcccggc 3541 gccacggcgg gagctaggcc agagggagac gcgcctccct cccctctctt gtcttccccg 3601 ccttagctga cggccgccag ctcgtgctgc tacccccgcg agggctggag gtactcccgc 3661 gagcacaacg ccatcctcgg gccctttggc gagcttatga ccgaagccga catcctccgc 3721 atcgagcagc aaatcgagaa cctgcaggtg ctgcacaagg cgcagaagct ggaggcgcgc 3781 ctcgagcaac tggagctgga gctggagcag ctgctgccca tctcggccgc cctgtcggcg 3841 ccgcgcttca ccgtcgatcc gcgccgaatg catggccgcg ccgccagcct gcccgcctgg 3901 tgcagcaaga tctccacgtt gctcaagaac atggccacgc tgctggctgc gctgggcggc 3961 cggcctgcgc acctggcgga gctgctgacc gctgacacgg gccagccgct ggcgccgctg 4021 cccgacgcgc cctggctgcc cgggccgctc tgcctgggtc

gctcgcactc gctcagctgg

It would take over 250 slides to show the entire sequence of this one small piece of the DNA

DNA is such an important molecule that it can never leave the nucleus for fear it would be damaged. The

only time it is outside the nucleus is during cell division and then it converts into a special form.

To get the information out of the nucleus to the ribosomes where the genetic code can be deciphered

and put to use requires another Nucleic Acid.

RNA

To help make sense of the long chain of bases the body breaks the long chain into smaller

groups called codons

Codons are three letter groups

CCAGTAGGTACGCCTTAGTCAGGTTCAGTCACGTACGGT

So instead of seeing this:

Your body sees this:

CCA GTA GGT ACG CCT TAG TCA GGT TCA GTC ACG TAC GGT

These are of the words of the genetic language.

There are 64 different codons or words.

Here is an example of how it works.

Here are a bunch of letters

THEBIGREDDOGATETHEOLDFATREDCAT

What does it say ?

THE BIG RED DOG ATE THE OLD FAT RED CAT

You broke the letters into three letter words or Codons

The three base Codons is actually code words for specific Amino Acids – the building blocks of Proteins

AGC – Alanine

CCG – Theonine

ATT – Phenolalanine

CCA – Alanine

TTG - Glycine

These are single amino acids that combine to form a larger protein

Regulatory Sequences:

DNA RNA

TAC AUG Start sequence

ATT UAA Stop

ACT UGA Stop

ATC UAG Stop

mRNA Coding Sequence