Question of the DAY Jan 5 In prokaryotes, DNA molecules are _______ in shape and located in the _________. In prokaryotes, DNA molecules are _______ in shape and located in the _________. A. square, cytoplasm A. square, cytoplasm B. helical, nucleus B. helical, nucleus C. circular, cytoplasm C. circular, cytoplasm D. twisted, mitochondria D. twisted, mitochondria

DO NOW Jan 5 How is genetic information stored within our cells? How is genetic information stored within our cells?

DO NOW ANSWERED Jan 5 Humans have 46 chromosomes. Humans have 46 chromosomes. Chromosomes are made of DNA. Chromosomes are made of DNA. Each chromosome contains genes that code for specific traits. Each chromosome contains genes that code for specific traits. Genetic Blueprints. Genetic Blueprints.

The Universal Language of Life In this chapter, we will explore… In this chapter, we will explore… Early scientific research leading to the discovery of DNA. Early scientific research leading to the discovery of DNA. The processes responsible for copying DNA and protein synthesis. The processes responsible for copying DNA and protein synthesis. Replication Replication Transcription Transcription Translation Translation

Chapter 12: DNA and RNA

12-1: Discovering DNA Frederick Griffith (1928) Frederick Griffith (1928) Worked to find better ways to fight pneumonia Worked to find better ways to fight pneumonia Smooth (S) deadly form Smooth (S) deadly form Rough (R) nondeadly form Rough (R) nondeadly form

Griffith’s Experiment Injected mice with… Injected mice with… R-strain: Nonvirulent R-strain: Nonvirulent S-strain: Virulent S-strain: Virulent Heat Killed S-Strain Heat Killed S-Strain R + Heat Killed S R + Heat Killed S

Griffith’s Results Injected mice with… Injected mice with… R-strain  ? R-strain  ? S-strain  ? S-strain  ? Heat Killed S-Strain  ? Heat Killed S-Strain  ? R-strain + Heat Killed S  ? R-strain + Heat Killed S  ?

Griffith’s Results

What killed the mouse? Why did the R-strain and heat killed S- strain combination kill the mouse? Why did the R-strain and heat killed S- strain combination kill the mouse?

Transformation when one type of bacteria is changed into another when one type of bacteria is changed into another realized some molecule changed harmless rough bacteria into deadly smooth bacteria realized some molecule changed harmless rough bacteria into deadly smooth bacteria

Oswald Avery (1944) Found transformation was blocked when DNA was destroyed Found transformation was blocked when DNA was destroyed Concluded genes are made up of DNA Concluded genes are made up of DNA

Avery’s Experiment Treated the R-strain and heat killed S- strain bacteria with enzymes Treated the R-strain and heat killed S- strain bacteria with enzymes Proteins were destroyed → mouse died Proteins were destroyed → mouse died DNA was destroyed → mouse lived DNA was destroyed → mouse lived DNA is the transforming factor DNA is the transforming factor

Alfred Hershey and Martha Chase (1952) Bacteriophages: type of virus that infects bacteria Bacteriophages: type of virus that infects bacteria Made of protein and DNA Made of protein and DNA used radioactive isotopes used radioactive isotopes What are they? What are they?

Hershey and Chase Animation hill.com/olcweb/cgi/pluginpop.cgi?it=swf::5 35::535::/sites/dl/free/ / /bio21.swf::Hershey%20and%20Chase%2 0Experiment hill.com/olcweb/cgi/pluginpop.cgi?it=swf::5 35::535::/sites/dl/free/ / /bio21.swf::Hershey%20and%20Chase%2 0Experiment hill.com/olcweb/cgi/pluginpop.cgi?it=swf::5 35::535::/sites/dl/free/ / /bio21.swf::Hershey%20and%20Chase%2 0Experiment hill.com/olcweb/cgi/pluginpop.cgi?it=swf::5 35::535::/sites/dl/free/ / /bio21.swf::Hershey%20and%20Chase%2 0Experiment Summarize the steps of the experiment in your notebooks. Summarize the steps of the experiment in your notebooks.

Hershey and Chase

Hershey and Chase’s Results Labeled the DNA and protein with radioactive isotopes Labeled the DNA and protein with radioactive isotopes labeled DNA with phosphorus-32 labeled DNA with phosphorus-32 labeled protein with sulfur-35 labeled protein with sulfur-35 Found P-32 in bacterium Found P-32 in bacterium Concluded genetic material of bacteriophage must be DNA  WHY? Concluded genetic material of bacteriophage must be DNA  WHY?

12-2: DNA Structure and Replication DNA DNA deoxyribonucleic acid deoxyribonucleic acid What is the monomer of a nucleic acid? What is the monomer of a nucleic acid? What are the three parts that make up one of these monomers? What are the three parts that make up one of these monomers?

DNA and Chromosomes genetic information is on chromosomes genetic information is on chromosomes Made up of chromatin Made up of chromatin DNA and protein DNA and protein histones: class of proteins that bind directly to DNA histones: class of proteins that bind directly to DNA form tiny particles called nucleosomes form tiny particles called nucleosomes help to unfold and package DNA help to unfold and package DNA

Nucleotides adenine (A) adenine (A) cytosine (C) cytosine (C) guanine (G) guanine (G) thymine (T) thymine (T) What comparison can you make about the four nucleotides in the diagrams? What comparison can you make about the four nucleotides in the diagrams?

Chargaff’s Rules (1950) amounts of adenine and thymine were the same amounts of adenine and thymine were the same amounts of cytosine and guanine were the same amounts of cytosine and guanine were the same

Applying Chargaff’s Rule A sequence of DNA contains base pairs. A sequence of DNA contains base pairs. If there were 2900 Guanines in the sequence, how many Adenines are in the sequence? If there were 2900 Guanines in the sequence, how many Adenines are in the sequence?

Rosalind Franklin (1951) used x-ray diffraction: x-ray beam is aimed at a sample used x-ray diffraction: x-ray beam is aimed at a sample X-ray is scattered and pattern recorded on film X-ray is scattered and pattern recorded on film unlocked clues to DNA structure unlocked clues to DNA structure

Rosalind Franklin The Unsung Hero IlEU IlEU IlEU IlEU

Watson and Crick Unlocked the structure of DNA Unlocked the structure of DNA Two complementary strands Two complementary strands double helix double helix bonds between nitrogenous bases hold strands together bonds between nitrogenous bases hold strands together base pairs base pairs A=T and G=C A=T and G=C

Replication Process in which DNA is copied Process in which DNA is copied Molecule separates into two strands. Molecule separates into two strands. Each template strand produces a new complementary strand. Each template strand produces a new complementary strand. Requires DNA Polymerase Requires DNA Polymerase What kind of molecule is this? What kind of molecule is this?

DNA Replication Double helix structure explained how DNA is copied. Double helix structure explained how DNA is copied. Each strand contains all of the information needed to construct the other half. Each strand contains all of the information needed to construct the other half. Rules of base pairing: A = T Rules of base pairing: A = T G = C G = C

HOMEWORK Play the “DNA Game” Play the “DNA Game” Visit the Nobel Prize Website included on your homework. Visit the Nobel Prize Website included on your homework. Follow the directions on the website. Follow the directions on the website. Record the results of each game on the answer sheet. Record the results of each game on the answer sheet.

DNA Replication A DNA molecule has 2 strands. A DNA molecule has 2 strands strand strand strand strand Each new strand copied is complementary to its parent (template) strand. Each new strand copied is complementary to its parent (template) strand.

ENZYMES found in Replication HELICASE – Enzyme that unwinds DNA before replication. HELICASE – Enzyme that unwinds DNA before replication. DNA POLYMERASE - Enzyme that joins individual nucleotides together to produce a DNA molecule. DNA POLYMERASE - Enzyme that joins individual nucleotides together to produce a DNA molecule. “Proofreads” new DNA strands for errors. “Proofreads” new DNA strands for errors. Copy the following template strand of DNA Copy the following template strand of DNA ATTCGGTGACCGGGAT ATTCGGTGACCGGGAT

Replication in Organisms PROKARYOTES Starts at a single point Starts at a single point Two directions Two directions Copies entire chromosome Copies entire chromosome In what part of the cell does replication occur? In what part of the cell does replication occur? EUKARYOTES Occurs in many different places along DNA molecule Occurs in many different places along DNA molecule Proceeds in two directions Proceeds in two directions Copies entire chromosome Copies entire chromosome In what part of the cell does replication occur? In what part of the cell does replication occur?