dna basics deoxyribonucleic acid. every living organism has dna. every living thing has it’s own...

DNA BasicsDeoxyribonucleic Acid

Every living organism has DNA

Every living thing has itrsquos own unique DNA

But DNA is DNA andhellip

According to Nat Geo we share 96 of the DNA chimps have and share 50 with a banana

Watson and Crick figured out the structure of the DNA molecule

But it was Rosalyn Franklin who had the photograph that made everything make sense

Stolen Photo - 51

DNA is found in the nucleus

DNA is found only in the nucleus it is so important it canrsquot leave the nucleus

-------ever--------

Your DNA is your blueprint or building instructions

It is your complete instruction manuel for how to build repair and replace you

(Your DNA codes for building proteins)

A rose by any other namehellipRomeo and Juliet

1 DNA by any other name

2-3Chromatin

4 Chromosomes

5 Sister Chromatidsbull Deoxyribonucleic Acid

will still carry your code

How is DNA structured

The entire molecule is twisted into a double helix

DNA is a polymer made of monomers called nucleotides

bull Larry the Cable guy would just say something like this

bull Itrsquos somrsquon perdy big thatrsquos made from lots of little bitty things that are perdy small

bull But itrsquos all perdy small really

bull Yor teacher said learn it

The nucleotides are composed of 3 things

bull Phosphate groupbull Deoxyribose sugar

bull Nitrogen base

Nitrogen Bases are Adenine Thymine Guanine and Cytosine

A-TG-C

The DNA backbone is made of a Sugar and a phosphate

The steps of the ladder are the nitrogen bases that are held together by weak

HYDROGEN BONDS

(Hydrogen high-school

heartbreak bonds ndash easily broken)

Replication If something needs repair or you

just need more

bull DNA unzips and makes an exact copy of itself during interphase of the cell cycle

If your body needs to build something it is called

protein synthesis

bull Synthesis (putting something together)

Why is protein important to me

All livings need protein forhellipeverythinghellip

80 of every cell is made of protein

Enzymes speed up reactions

Hormones send signals

DNA needs to make a protein but DNA doesnt speak the

language that proteins speak

english and arabic

You have to have a translator

1 strand 2strands

mRNA DNA1 one strand two strands

2 AUGC ATGC

3 Ribose Deoxyribose

There are 2 steps in protein synthesis

Transcription ndash a script is a copy

Translation ndash latethis is the last part

Transcription (part 1)bullDNA strand stays in the nucleus

bullDNA unzips (enzyme called polymerase)

bullmRNA comes into the nucleus and makes a copy because DNA cannot leave the nucleus

bull MRNA uses a nitrogen base called uracilbullmRNA takes a copy to a ribosome in the

cytoplasm bullDNA zips back up and you have the original and

a copy toobullQuestions

Questionsbull What makes a copy of the

DNA

bull Where is the copy made

bull Where is the copy taken

bull What sugar is in DNA RNA

bull Why can DNA not leave the nucleus

bull What are the 3 differences between DNA and RNA

bull DNA strand ishellip GTCATACCA mRNA strand is

Translation (part2)

tRNA is the worker It carries amino acids but it only reads in 3rsquos

It translates mRNA into short a 3 letter words

mRNA has the real code

tRNA has the matching code (or anticode) that matches the correct amino acid

rRNA

All of this happens at the ribosome or the rRNA

bull One by one these tRNA bring amino acids to link into a protein chain according to the DNA instructions

bull How amazing is thatbull Should we be clapping now

Review the steps of Protein Synthesis

1 Transcription (writing the ldquomessagerdquo)

1048766DNA mRNA messenger carries code

2 Translation (reading the ldquomessagerdquo)

1048766mRNA tRNAprotein (AA chain)message translated into a proteinmessenger carries codeto cytoplasmto cytoplasm

DNA Replication

DNA unwinds and makes a copy

(Itrsquos that simple)

This creates a replication bubble to copy only what is needed

For making big copies the DNA will start copying at different places at the same time to work faster

Mutationsare not always bad

Mutations can be caused by

bull Errors in replication (DNA-DNA)

bull Errors in transcription (DNA-RNA)

bull Cell Division ndash (Cancer)

bull External Agents ndash UV radiation chemicals smoking

Mutation Types

1 Point mutation

bull The dog bit the catbull The dog bit the car

bull Only one letter is changed but the meaning is very different

bull wwwygyhorgcfcausehtm

Mutation Types2 Frameshift Mutation

bull The dog bit the catbull The dob itt hec at

bull The ldquogrdquo is lost but everything is still read in groups of 3rsquos

bull Since the language of DNA is in codons (groups of 3 nucleotides) it can only translate in 3rsquos

Glencoe 347

sickle cell (ygyh)

338 codon chart

bull Point Mutations ndash changes in one or a few nucleotides

Substitution THE FAT CAT ATE THE RAT THE FAT HAT ATE THE RAT

Insertion THE FAT CAT ATE THE RAT THE FAT CAT XLW ATE THE RAT

Deletion THE FAT CAT ATE THE RAT THE FAT ATE THE RAT

Changes in number and structure of entire chromosomes

Original Chromosome ABC DEFDeletion AC DEFDuplication ABBC DEFInversion AED CBFTranslocation ABC JKL

GHI DEF

Chromosome Mutations

Translocation

bullMost are neutralbull Eye colorbull Birth marks

bullSome are harmfulbull Sickle Cell Anemiabull Down Syndrome

bullSome are beneficialbull Sickle Cell Anemia to Malariabull Immunity to HIV

Significance of Mutations

Nature shuffles our genesThe mutation of brown eyes to blue represents neither a positive nor a negative mutation It is one of several mutations such as hair colour baldness freckles and beauty spots which neither increases nor reduces a humanrsquos chance of survival

Originally we all had brown eyesrdquo said Professor Eiberg from the Department of Cellular and Molecular Medicine ldquoBut a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a ldquoswitchrdquo which literally ldquoturned offrdquo the ability to produce brown eyesrdquo

University of Copenhagen (2008 January 31) Blue-eyed Humans Have A Single Common Ancestor ScienceDaily Retrieved February 27