Deoxyribonucleic acid The Importance of DNA Deoxyribonucleic acid Nucleic acid Native Americans

In biology, form = function Things are “shaped” for what they do. The molecule DNA is beautifully designed to carry out its functions (jobs) perfectly. This is a picture of a portion of a molecule of DNA! THE DOUBLE HELIX

DNA has two jobs (functions) 1. DNA is the BLUEPRINT/CODE for the organism’s proteins DNA makes RNA makes Protein We are protein machines If it isn’t made out of protein (muscle, pigments, etc) ….it’s made by proteins (enzymes, cell receptors) 2. DNA is the GENETIC MATERIAL DNA is copied into every new cell (mitosis) DNA is passed-on to off-spring (meiosis/fertilization) Red words only

The Molecule DNA consists of: A double-stranded backbone made of ribose sugar and phosphate molecules. The 2 upright parts of the ladder 4 Bases (nitrogenous bases) The rungs of the ladder

4 Nitrogenous Bases in DNA C = Cytosine G = Guanine A = Adenine T = Thymine Rules for DNA Base Pairing C pairs with G T pairs with A Dotted lines = Hydrogen bonds deoxyribose sugar

Complementary Base Pairing Thymine Adenine Guanine Cytosine Adenine T is the complement to A Adenine Thymine C is the complement to G Thymine Adenine Cytosine Guanine Adenine Thymine Cytosine Guanine Guanine Cytosine

Form = Function DNA’s two special features makes it really good at doing its job! Complementary base pairing means the code can be transferred to RNA That’s how DNA makes RNA It can unzip at these hydrogen bonds for easy replication

FORM = FUNCTION (Job) Genetic Material hydrogen bonds between paired bases are somewhat weak. The two sides of DNA split apart pretty easily DNA gets duplicated (copied) after it splits apart Each side of the ladder is a template for the new molecule of DNA DNA

DNA Replication DNA unzips and unwinds with the help of enzymes Free nucleotides in the nucleus base pair with the exposed strands Two new strands are created identical to the starting strand and each other

DNA Replication Each new DNA molecule keeps one strand from the original starting molecule AND a builds a brand new matched strand from free nucleotides in the nucleus. A GOOD WAY TO AVOID ERRORS! Errors = mutations

animation http://biotech-adventure.okstate.edu/low/basics/dna_replication/replication2/

DNA codes for Proteins DNA makes RNA makes Proteins The process of protein synthesis (synthesis = making) How does DNA do this?

DNA is a Big Molecule Fun Facts! Each nucleus of each cell in your body has 6’ of DNA in it You have about 9 million kilometers of DNA. That's enough to reach to the moon and back 13 times! 

DNA is stuck in the nucleus It can’t get out….it’s just too darned big Besides, it’s important stuff so it’s a good thing that it’s protected inside the nucleus BUT proteins are big too…. Proteins are needed both outside and inside the nucleus DILEMMA….what should DNA do? DNA makes a messenger to do the job outside of the nucleus mRNA or messenger RNA Red words

DNA makes RNA (aka Transcription) RNA = ribonucleic acid There are several kinds of RNA mRNA (m = messenger) Holds the code for proteins tRNA (t = transfer) Transfers the correct amino acid rRNA (r = ribosomal) Makes up part of the ribosome RNA is like DNA (both are nucleic acids) but slightly different It is single stranded (not a double helix like DNA) Instead of T (thymine) it has U (uracil) So the A of DNA base pairs with U when making RNA

T G T C A C A G T G C A G A A G G A T C A U C C C U G A G T C T A A G G A C T T C C A strand of RNA is made using the DNA as a template

The amino acid is attached here tRNA a rRNA (ribosome) anticodon Form = Function

m m enzyme Transcription: x m Transcription: A single-stranded mRNA being assembled using DNA as the template. Since there is no T in RNA each A is paired with URACIL = U. DNA also makes tRNA and rRNA.

RNA makes Protein (aka Translation) A portion of the code protected in DNA (a GENE) gets transcribed to a strand of messsenger mRNA. One gene’s worth of mRNA leaves the nucleus and finds a ribosome and tRNA Once assembled, more tRNAs deliver amino acids to the strip of mRNA in the correct order. Therefore the nucleic acid code gets translated into an amino acid code. The amino acids bind together in a longer and longer strand to make the protein coded for by the gene

http://www.wiley.com/legacy/college/boyer/0470003790/animations/animations.htm

Translation to Protein gene DNA A T G C C A C T A G C A C G T T A C G G T G A T C G T G C A Sense strand Transcription to mRNA T A C G G T G A T C G T G C A codon codon codon codon codon There’s no T in RNA! Translation to Protein Use the universal genetic code

After the Protein is built The string of amino acids is released from the ribosome/mRNA complex Because the amino acids have different charges (positive or negative like a magnet) they attract or repel each other This causes the amino acid chain to fold up into a 3-dimensional shape. Each protein has its own particular shape Each protein folds up the same way every time

Proteins fold up into a 3-D shape Different charges of amino acids repel or attract each other Each protein has its own special shape Each protein folds up the same way every time If a protein doesn’t fold it can’t do its job

Sickle Cell Anemia A disease that is the result of a mutation in DNA which results in a protein that doesn’t fold up right

Normal Red Blood Cells Contain hemoglobin molecules (made from Protein) Hemoglobin folds to a shape that is great at carrying oxygen The shape of hemoglobin gives RBC’s their shape

Sickled Red Blood Cells Mutation in DNA changes the order of amino acids in Hemoglobin. The protein folds slightly differently The mutation makes the RBCs look like sickles.

The chain of amino acids is only slightly different…but it’s enough to cause this chain to fold up into a different shape.

How does this cause disease? The shape of the cell is not good at carrying oxygen. FATIGUE lack of ATP The cell gets stuck in veins causing severe pain

The sickle cell mutation is a like a typographical error in the DNA code of the gene that tells the body how to make a form of hemoglobin (Hb), the oxygen-carrying molecule in our blood. Every person has two copies of the hemoglobin gene. Usually, both genes make a normal hemoglobin protein. When someone inherits two mutant copies of the hemoglobin gene, the abnormal form of the hemoglobin protein causes the red blood cells to lose oxygen and warp into a sickle shape during periods of high activity. These sickled cells become stuck in small blood vessels, causing a "crisis" of pain, fever, swelling, and tissue damage that can lead to death. This is sickle cell anemia. http://www.pbs.org/wgbh/evolution/library/01/2/l_012_02.html

A section of DNA that codes for a protein is called a GENE Gene Expression A section of DNA that codes for a protein is called a GENE

Cells What is your body made out of? 46 Chromosomes, made out of DNA and consisting of segments of DNA called genes What is in the nucleus of each cell? What does the DNA (46 chromosomes/genes) do? Code for all of the proteins that your body needs to make to be you. What is in the nuclei of the cells in your eyes? 46 chromosomes

What is in the nuclei of your spleen cells? A copy of the same 46 chromosomes A copy of the same 46 chromosomes What is in the nuclei of cells in your heart? So, if a copy of the same 46 chromosomes is in every cell…how come cells in the eyes make eye proteins and cells in the spleen make spleen proteins and cells in the heart make heart proteins? GENE EXPRESSION: only the proteins needed by a certain type of cell are produced (or expressed) in that cell.

Gene Regulation: genes can be turned on and turned off depending on which type of cell needs the protein

Cloning, and recombining and counseling OH MY… Genetic Engineering Cloning, and recombining and counseling OH MY…

Recombinant DNA Technology A gene is inserted into bacterial DNA The bacteria (and their DNA) are replicated The bacteria express the gene that was inserted into them The protein that gene produces is used by humans.

Recombinant DNA Gene that codes for the protein INSULIN The bacteria expresses the insulin gene, the protein insulin is made and given to Diabetes patients. Plasmid DNA

Recombinant DNA Technology Gives us: Insulin Growth Factors Clotting Factors And more

Genetically Altered Plants Insert a gene into a plant that makes the plant resistant to certain insect pests Genetically alter cotton plants to produce non-white cotton.

Cloning Dolly the sheep Cloning to produce stem cells Is cloning to produce off-spring ethical? Is cloning to produce stem cells ethical?

Cloning for Stem Cells 23 46 Stem cell from same woman Unfertilized Egg Cell 46 Replace the egg nucleus with the stem cell nucleus and add growth factors. The new cell divides to the BLASTULA stage and the more powerful stem cells are harvested.

Genetic Counseling Parents can know before a child is born if they will have certain genetic problems Cystic fibrosis Parkinsons disease Marfan’s Syndrome And more