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Introduction l'ADN Gntique: Structure et fonction

PHA Biology 9Moretti/ DicksonIntro la gntique: Structure de l'ADN et fonctionGenetics: the study of heredityWhat determines an organisms traits (characteristics)?How are traits passed on from one cell to another, and from parents to offspring?DNA: the molecule that carries genetic informationDNA has two important functions:Replicate make exact copies of itself so it can be passed onCarry instructions for making proteins that determine your traitsDNA is found in all cells (in the nucleus in eukaryotic cells)

Gntique: l'tude de l'hrditQu'est ce qui dtermine les traits d'un organisme (caractristiques)?Comment sont les traits transmis d'une cellule l'autre, et des parents aux enfants?ADN: la molcule qui transporte l'information gntiqueADN a deux fonctions importantes:Rpliquer - faire des copies exactes d'elle-mme afin qu'il puisse tre transmisEffectuer des instructions pour fabriquer des protines qui dterminent vos traits

L'ADN se trouve dans toutes les cellules (dans le noyau des cellules eucaryotes)

DNA Structure and Function

What is it?DNA = Deoxyribonucleic AcidWhere do we find it?Found in the NucleusWhat does it do?Carries your genesCarries information to make the proteins that make your traits

Objectives for Class:Explain how DNA, genes, nucleotides, and chromosomes relate to each other.Describe the structure of DNA.

Nucleotide Base PairsDNA ChromosomesGene: Instructions for making a protein that determines a traitAnother Gene: instructions for making a different protein that determines a different trait

DNA Structure and Function(refer to handout)Chromosomes unraveling into DNA DNA Structure

Objectives for Class:Explain how DNA, genes, nucleotides, and chromosomes relate to each other.Describe the structure of DNA.DNA Structure Building Blocks = NucleotideDeoxyribose SugarPhosphateNitrogenous Base

Nucleotides put together: Ladder: UncoiledDouble Helix: 2 long coiled strandsSides: alternating phosphates & sugarsMiddle/ Rungs of ladder: 2 Nitrogenous Bases connected by Hydrogen bonds

Objectives for Class:Describe the structure of DNA.Identify the monomers of the DNA polymer

DNA Structure: Nucleotides Objectives for Class:Describe the structure of DNA.Identify the monomers of the DNA polymerDNA Structure: Base Pairing4 Nitrogen Bases: Adenine GuanineThymine Cytosine

Base Pairing:A ---- TG ---- C

} Purine} Pyrimidine

Objectives for Class:Identify

DNA Structure: Images

Objectives for Class:Explain how DNA, genes, nucleotides, and chromosomes relate to each other.Describe the structure of DNA.

DNA Structure: Nucleotides Objectives for Class:Describe the structure of DNA.Identify the monomers of the DNA polymerComplete the DNA Review (other side of the DNA/ Chromosome Handout)

DO NOW: Write down this DNA Sequence:G A T A C A T G C G C T A T G T A C G C

What is the sequence for the complementary (aka matching) DNA strand?

Nucleotide Base PairsDNA ChromosomesGene: Instructions for making a protein that determines a traitAnother Gene: instructions for making a different protein that determines a different trait

DNA Structure and Function(refer to handout - review)Chromosomes unraveling into DNA DNA Replication: Overview DNA can make an exact copy of itself!Occurs every time a cell needs to reproduce(during S-phase of the cell cycle)

Objectives for Class:Describe the structure of DNA.Explain WHY DNA must replicate and the 3 steps of HOW DNA replicates.

Objectives for Class:Describe the structure of DNA.Explain WHY DNA must replicate and the 3 steps of HOW DNA replicates.DNA Replication: Overview

Steps of DNA Replication1. DNA Unzips:Enzyme breaks Hydrogen Bonds between base pairsCreates 2 Complementary Strands (templates)2. DNA Polymerase moves along original strands (templates)Nucleotides come from the cytoplasm DNA Polymerase attaches complimentary bases to both sides of the unzipped strands (Semi-Conservative).3. Completed: 2 NEW identical strands of DNA are producedDNA Polymerase proofreads the new strands

Objectives for Class:Describe the structure of DNA.Explain WHY DNA must replicate and the 3 steps of HOW DNA replicates.

DNA Replication

Note: The RED Strand is the Original StrandObjectives for Class:Describe the structure of DNA.Explain WHY DNA must replicate and the 3 steps of HOW DNA replicates.Do Now1. Write the complementary base sequence to this single strand of DNA2. Which of the pictures below best illustrates DNA replication? Why? G A A C G T

A.B.C.

17DNA Model Building Lab: Part IPart I: Constructing DNABuild 36 nucleotides:

Count out the following and put the rest in a pile for later:5 A 5 T4 C4 GBuild a double-stranded DNA molecule with these 18 nucleotidesRecord your DNA Sequence in the tableThen answer the questions and go on to Part 2

Objectives for Class:Describe the structure of DNA.phosphatesugarNit.baseDNA Model Building Lab: Part IIPart II: Replicating DNAUnzip your DNA sequence by breaking the hydrogen bond between the two nitrogenous bases. Observe your two separate strands. Using the other pieces in your kit, create two new strands of DNA nucleotide by nucleotide. Note that when the DNA molecule splits in half, new complimentary bases attach to the separated strands creating two new strands of DNA. Be sure your base pairs match!Be sure to construct your new DNA strand by adding nucleotides to the original templates!When finished:Take all pieces apart and put them back in the bagsAnswer the Discussion Questions for Part 2

Objectives for Class:Describe the structure of DNA.Explain WHY DNA must replicate and the 3 steps of HOW DNA replicates.