DNA DNA Deoxyribonucleic Acid n A cells code

DNA

DNA Deoxyribonucleic Acid n A cell’s code / recipe / blueprint n Biological instructions that make each species unique n Genetic instructions used in the development and functioning of all known living organisms

What Does DNA Look Like? n Similar to a ‘twisted ladder’ n Each side of the ladder is made up of SUGAR -PHOSPATE MOLECULES – Sugar group deoxyribose – Phosphate molecule n Rungs(steps) of the ladder are nitrogen bases – DNA has 4 types of nitrogen bases n Nitrogen bases are connected by hydrogen bonds

NITROGEN BASES n 4 types of Nitrogen Bases – Adenine (A) – Thymine (T) – Guanine (G) – Cytosine (C)

NITROGEN BASES n Nitrogen bases occur in pairs in DNA. – Adenine pairs with Thymine – Guanine pairs with Cytosine n Like pieces of a puzzle, each base bonds only with its correct partner.

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If this code makes up one side of the DNA, what would the code be for the other side? A T C G A A C T T G A C A G

If this code makes up on side of the DNA, what would the code be for the other side? A T C G A A C T T G A C A G T A G C T T G A A C T G T C

NUCLEOTIDE 1 base + 1 Sugar + 1 Phosphate = Nucleotide

Who Discovered DNA? n James Watson and Francis Crick n Rosiland Franklin, a woman, discovered the double helix shape of DNA and had the best X-ray picture at the time. n Maurice Wilkin, her colleague, didn’t want a woman to get the credit for discovering DNA so he stole her picture and gave it to Watson and Crick. n The picture along with their research help Watson and Crick create the first correct model of DNA. n Watson, Crick, and Wilkin were awarded the Nobel Peace Prize in 1962. Franklin died of cancer 4 years earlier.

Joined Nucleotides = GENES n Gene sequence of DNA that occupies a specific location on a chromosome and determines a particular characteristic in an organism. n Each cell in the human body contains about 25, 000 to 35, 000 genes Genes carry information that determines your traits. Traits are specific features you inherit from your parents. n

PROTEIN Groups of 3 nucleotides from a DNA sequence make AMINO ACIDS n Ribosomes connect amino acids into long chains n Long chains of amino acids = PROTEIN n Proteins are the building blocks for everything in your body. n – Bones and teeth, hair and earlobes, muscles and blood, all are made up of proteins. – Those proteins help our bodies grow, work properly, and stay healthy.

CHROMOSOMES GENES + PROTIENS (built with the ribosomes and codes of DNA) = CHROMOSOMES n There are hundreds to thousands of genes on each chromosome n Chromosomes are located in the nucleus of the cell n Each person has 23 pairs (46 total) of chromosomes. – 23 chromosomes come from your father, 23 from your mother.

The DNA coils around proteins made up of amino acids

DNA REPLICATION n DNA unwinds. n The original strands serve as templates for two new strands. n DNA POLYMERASE connects to the original strands and begins to create new DNA. n Once DNA is replicated, the chromosome also splits.

MUTATIONS n A mutation is a permanent change in the DNA sequence of a gene. n Mutations in a gene's DNA sequence can alter the amino acid sequence of the protein. n Mutations can be positive, negative, or neutral – EX: Disease, missing body part/function, heightened senses, bigger and stronger, doubled jointed n Mutations randomly cause adaptations

TYPES OF MUTATIONS n Environmental Factors – Sunlight (skin cancer, wrinkles, etc), – Smoking (lung or throat cancer, lung disease, etc) – Radiation n DNA Replication Error – Point Mutation – Frame-shift Mutation

POINT MUTATION n A point mutation is a simple change in one base of the gene sequence ( A paired with G instead of T). n This is equivalent to changing one letter in a sentence, such as this example, where we change the 'c' in cat to an 'h': – The fat cat ate the wee rat. – Point Mutation: The fat hat ate the wee rat. n The gene will now have a mutation, or change, compared to the original.

FRAME-SHIFT MUTATION n In a frame shift mutation, one or more bases are inserted or deleted (A, T, C, or G accidentally doesn’t get copied), the equivalent of adding or removing letters in a sentence. n Because our amino acids are created from DNA in three letter "words“ or codes, adding or removing one letter changes all of the following words. n An example of a frame-shift mutation using our sample sentence is when the 't' from cat is removed, but we keep the original letter spacing: – The fat cat ate the wee rat. – Frame Shift: The fat caa tet hew eer at.