DNA replication transcription translation How you go from

DNA replication, transcription, & translation How you go from DNA to proteins

Watson & Crick In 1953, Watson & Crick discovered the structure of DNAthe… double helix

Remember Where is DNA? DNA is in the nucleus of cells What is made up of DNA? Chromosomes are made up of DNA

Remember as well… • Before a cell divides (mitosis) it has to do what? • Copy its DNA, (and grow)

DNA replication An enzyme unzips (or takes apart) the double helix Each strand acts as a template for the new strand A T C G get added to the growing strand An enzyme “proofreads” or double checks the new DNA to make sure there are no mistakes

Watch DNA replication http: //www. stolaf. edu/peop le/giannini/flashanimat/mol genetics/dna-rna 2. swf http: //www. hhmi. org/bioint eractive/media/DNAi_repli cation_vo 1 -lg. mov

DNA contains genes Genes are parts of the DNA that code for traits But how do we get from DNA to traits that we see?

First DNA is used to make RNA This process is called transcription RNA replaces T with U! This type of RNA= messenger RNA, or m. RNA

Watch transcription http: //wwwclass. unl. edu/biochem/gp 2/m_biology/animation/gene/ gene_a 2. html Transcription

Review: Transcription Enzyme unzips DNA RNA polymerase starts transcription RNA bases are matched to one strand of DNA RNA strand is released

DNA is a double helix, RNA is not!

PRACTICE! Write the DNA strand: ACGGCTTACTGGCATT Now you figure out the RNA strand. Answer: UGCCGAAUGACCGUAA

Messenger RNA m. RNA carries the message of your genetic code It leaves the nucleus and goes into the cytoplasm where there are ribosomes

Genetic Code Now you have m. RNA carrying the genetic code You read the sequence of letters 3 bases at a time: UCG-CAC-GGU The 3 letter codes are called codons and stand for an amino acid: UCG-CAC-GGU Serine-Histidine-Glycine There are 20 amino acids that make up ALL the proteins in your body!

1. GCU PRACTICE: 2. AAA 3. CGA 4. UUC

From RNA to protein This process is called Translation m. RNA attaches to ribosome – r. RNA found in ribosome acts as translator t. RNA anticodons match up with m. RNA codons and carry the amino acid The amino acids bond together to form a protein

Watch translation. . TWICE! http: //www. stolaf. edu/people/giannini/flashanimat/molg enetics/translation. swf http: //wwwclass. unl. edu/biochem/gp 2/m_biology/animation/gene/ gene_a 3. html

REVIEW! DNA replication gives us: 2 copies of DNA Transcription gives us: m. RNA Translation gives us: amino acid chain (protein!) Proteins give us traits!