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Intro to Genetics: DNA Structure & Function. 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
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Intro to Genetics:DNA Structure & Function • 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: • Carry instructions for making proteins that determine your traits • Replicate – make exact copies of itself so it can be passed on • DNA is found in all cells (in the nucleus in eukaryotic cells)
Genetic Info in Cells Chromosomes Very long, coiled/bunched up strands of DNA that contain many genes Nucleotide Base Pairs Building blocks of DNA DNA Gene:Instructions for making a protein that determines a trait Another Gene: instructions for making a different protein that determines a different trait
DNA Structure • Objectives for Class: • Describe the structure of DNA.
DNA Structure • DNA is made out of Nucleotides • Nucleotides have 3 parts: • Deoxyribose Sugar • Phosphate • Nitrogenous Base (A, T, C, or G) • DNA molecule = double helix of nucleotides • Sides: alternating phosphates & sugars • Middle/ “Rungs” of ladder: • Pairs of Nitrogenous Bases connected by Hydrogen bonds • Objectives for Class: • Describe the structure of DNA.
Base Pairing • A ---- T Hydrogen bonds connect them • G ---- C • Objectives for Class: • Describe the structure of DNA.
DNA Structure: Images • Objectives for Class: • Describe the structure of DNA.
DNA Replication: Overview • DNA can make an exact copy of itself! • Occurs every time a cell needs to reproduce • What is the first thing that would need to happen to replicate this DNA? • Objectives for Class: • Describe the structure of DNA.
Steps of DNA Replication 1. Double helix splits (unwinds and unzips) • Hydrogen Bonds break • Separates into 2 single strands 2. New nucleotides match up with each side • DNA Polymerase is the enzyme that does this • Matches according to base-pairing rules 3. Two new strands twist up Result: Two Double Helices Each half old, half new. • Objectives for Class: • List the steps of DNA replication
Bio 9B: Friday, 2/17/12Title: DNA Review Homework: Optional - Finish Parts 2 and/or 3 of the DNA Review Packet Silent Do Now: (in notebook w/ title & date) 1. Write the complementary base sequence to this single strand of DNA 2. Which of the pictures below best illustrates DNA replication? Why? G A A C G T A. B. C. Bonus: Who is the perfect Valentine for a gentleman named CTCT?