Introduction à l'ADN Génétique: Structure et fonction

1. Introduction à l'ADN Génétique: Structure et fonction PHA Biology 9 Moretti/ Dickson

2. Intro à la génétique: Structure de l'ADN et fonction • Genetics: the study of heredity • What determines an organism’s traits (characteristics)? • How are traits passed on from one cell to another, and from parents to offspring? • DNA: the molecule that carries genetic information • DNA has two important functions: • Replicate – make exact copies of itself so it can be passed on • Carry instructions for making proteins that determine your traits • DNA is found in all cells (in the nucleus in eukaryotic cells) • Génétique: l'étude de l'hérédité • Qu'est ce qui détermine les traits d'un organisme (caractéristiques)? • Comment sont les traits transmis d'une cellule à l'autre, et des parents aux enfants? • ADN: la molécule qui transporte l'information génétique • ADN a deux fonctions importantes: • Répliquer - faire des copies exactes d'elle-même afin qu'il puisse être transmis • Effectuer des instructions pour fabriquer des protéines qui déterminent vos traits • L'ADN se trouve dans toutes les cellules (dans le noyau des cellules eucaryotes)

3. DNA Structure and Function • What is it? • DNA = Deoxyribonucleic Acid • Where do we find it? • Found in the Nucleus • What does it do? • Carries your genes • Carries 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.

4. DNA Structure and Function(refer to handout) Chromosomes Chromosomesunraveling into DNA Nucleotide Base Pairs DNA Gene:Instructions for making a protein that determines a trait Another Gene: instructions for making a different protein that determines a different trait

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

6. DNA Structure • “Building Blocks” = Nucleotide • Deoxyribose Sugar • Phosphate • Nitrogenous Base • Nucleotides put together: • Ladder: Uncoiled • Double Helix: 2 long coiled strands • Sides: alternating phosphates & sugars • Middle/ “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

7. DNA Structure: Nucleotides • Objectives for Class: • Describe the structure of DNA. • Identify the monomers of the DNA polymer

8. DNA Structure: Base Pairing • 4 Nitrogen Bases: • Adenine • Guanine • Thymine • Cytosine • Base Pairing: • A ---- T • G ---- C } Purine } Pyrimidine • Objectives for Class: • Identify

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

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

11. 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?

12. DNA Structure and Function(refer to handout - review) Chromosomes Chromosomesunraveling into DNA Nucleotide Base Pairs DNA Gene:Instructions for making a protein that determines a trait Another Gene: instructions for making a different protein that determines a different trait

13. 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.

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

15. Steps of DNA Replication 1. DNA Unzips: • Enzyme breaks Hydrogen Bonds between base pairs • Creates 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 produced • DNA 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.

16. DNA Replication Note: TheRED Strandis the Original Strand • Objectives for Class: • Describe the structure of DNA. • Explain WHY DNA must replicate and the 3 steps of HOW DNA replicates.

17. Do Now 1. Write the complementary base sequence to this single strand of DNA 2. Which of the pictures below best illustrates DNA replication? Why? A. B. C. G A A C G T

18. DNA Model Building Lab: Part I Part I: Constructing DNA • Build 36 nucleotides: • Count out the following and put the rest in a pile for later: 5 A 5 T 4 C 4 G • Build a double-stranded DNA molecule with these 18 nucleotides • Record your DNA Sequence in the table Then answer the questions and go on to Part 2 Nit. base phosphate sugar • Objectives for Class: • Describe the structure of DNA.

19. DNA Model Building Lab: Part II Part II: Replicating DNA • “Unzip” 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 bags • Answer 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.