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GETTING TO KNOW DNA. WHAT DO YOU ALREADY KNOW?. PART 1: KNOWING YOUR NUCLEOTIDES. DNA is the code that makes you who you are. The code has ONLY 4 LETTERS!!! A = Adenine T = Thymine C = Cytosine G = Guanine. PART 1: KNOWING YOUR NUCLEOTIDES. A, T, C, & G are nucleotides.
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PART 1: KNOWING YOUR NUCLEOTIDES • DNA is the code that makes you who you are. • The code has ONLY 4 LETTERS!!! • A = Adenine • T = Thymine • C = Cytosine • G = Guanine
PART 1: KNOWING YOUR NUCLEOTIDES • A, T, C, & G are nucleotides. • Nucleotides: The building blocks of DNA that match up to form the double helix shape • A + T bond • C + G bond
PART 1: KNOWING YOUR NUCLEOTIDES • Nucleotides all have the same general structure. • Phosphate Group is the backbone • Sugar is the link • Nitrogen Base is the code: A, T, C, G • The green base can change, but yellow and pink stay the same
PART 1: KNOWING YOUR NUCLEOTIDES • DNA is the code to make RNA. • RNA is the code to make proteins! • RNA replaces the deoxyribose sugar link of DNA with just a ribose sugar link • RNA also replaces the T nucleotide for a U • U = Uracil • A + U bonds
DNA HISTORY: ERWIN CHARGAFF (1950) • Erwin did the experiments to prove that A matches with T and that C matches with G in a 1 to 1 ratio.
DNA HISTORY: ROSALIND FRANKLIN (1951) • Rosalind took the first clear photo of DNA
DNA HISTORY: MARTHA CHASE & ALFRED HERSHEY (1952) • First to absolutely prove that DNA is the molecule that is the code for all genes
DNA HISTORY: FRANCIS CRICK & JAMES WATSON (1953) • Determined the “double-helix” shape of DNA from Rosalind’s photo. • Some say Rosalind got it first!
CHECK FOR UNDERSTANDING • What is a NUCLEOTIDE? • What are the 3 parts of a nucleotide? • Which nucleotide bonds with “A”? • Which nucleotide bonds with “C”? • Which nucleotide is replaced with “U” for RNA? • Which nucleotide bonds with “U”?
PART 2: DNA REPLICATION • We need to pass on our genes to new cells (by Mitosis) and to our offspring (by Meiosis). • DNA Replication is the process by which perfect copies of our DNA are made!
PART 2: DNA REPLICATION • Think of DNA as a zipper, two sides that are held together by matching base pairs. • The enzyme helicase unwinds the helix and forces the zipper to open! The Chainsaw!!!
PART 2: DNA REPLICATION • Opening the DNA causes “bubbles” to form • Replication can only happen when these single strands of DNA are exposed!
PART 2: DNA REPLICATION • Replication is “semi-conservative” because the original (parent) strands stay the same, while new matching (daughter) strands are added on.
PART 2: DNA REPLICATION • The nucleus is filled with a pool of extra nucleotides, waiting to make new DNA. • DNA Polymerase is like a train that rides along the rail of DNA and attaches matching base pairs.
CHECK FOR UNDERSTANDING • Why do the DNA strands need to be “unzipped” before they can be copied? • What is “semi-conservative” DNA replication? • In replication, parents strands are matched with new nucleotides to make a _________ strand.
PART 3: PROTEIN SYNTHESIS • Transcription: A process where a section of DNA code is copied into its matching RNA code. • Makes “messenger” mRNA
PART 3: PROTEIN SYNTHESIS • mRNA leaves the nucleus to find a ribosome in the cytoplasm.
PART 3: PROTEIN SYNTHESIS • Translation: The process of decoding the mRNA code • Every 3 letter code of mRNA (codon) = amino acid • Transfer RNA bring amino acids to match the codes of mRNA • Amino acids build the protein
PART 3: PROTEIN SYNTHESIS • mRNA codes for 20 different amino acids that have almost infinite combinations for making needed proteins.
COMPARING TO BUILDING A BUILDING • Architect's Office = Nucleus • The Master Plan by the architect = DNA • The location of the land to build the building = cytoplasm • The Blue Prints that communicate the Master Plan = mRNA
COMPARING TO BUILDING A BUILDING • The Supervisor at the site of construction = Ribosome • The concrete and lumber to build the building = amino acids • The trucks to bring the lumber = tRNA • The finished building = Complete Protein
CHECK FOR UNDERSTANDING • Now let’s compare building a protein to making a song. • The completed song = the completed protein • What is the recording studio? • What is the tape player? • What are the musical notes?