2 10.1 Discovery of DNA Griffith’s Experiments (1928) Griffith’s experiments showed that hereditary material can pass from one bacterial cell to another.The transfer of genetic material to one cell from another cell or from one organism to another organism is called transformation.
7 DNA – The Blueprint of Life Established by James Watson and Francis Crick (1950’s)DNA contains the instructions for making proteins within the cell.Shape of a double helixMade up of repeating sub-units called nucleotides
8 DNA codes for genesGene - A segment of DNA that codes for a protein, which in turn codes for a trait (skin tone, eye color…etc.), a gene is a stretch of DNA.
9 Deoxyribonucleic acid - DNA Monomer: nucleotidesEach nucleotides has:Deoxyribose sugarPhosphate group(1 of 4) nitrogen containing base
10 The 4 Bases in DNA are: Thymine (T) Cytosine (C) Guanine (G) Adenine (A)
11 Nitrogen Rings Purines have double rings of carbon-nitrogen (G, A) Pyrimidines have single carbon-nitrogen rings (C, T)
13 Complementary Base Pairing Base Pairing Rules1. C and G2. T and A
14 How do the nitrogenous bases stick together? Hydrogen bonds!3 H bonds hold G & C together2 H bonds hold T & A together
15 DNA Replication 10.3Occurs when chromosomes duplicate before mitosis & meiosisMakes an exact copy of the DNAH bonds between bases break and enzymes “unzip” the molecule
16 Steps of DNA Replication (pg. 201) Enzymes called helicases separate the DNA strand breaking the H bonds at the replication forkEnzymes called DNA polymerase add complementary nucleotidesDNA polymerase falls off when done replicating and the result is anidentical strand of DNA
18 Semi-conservative replication- Each old strand of nucleotides serves as a template for each new strand.
19 Another View of Replication Use of the ladder configuration better illustrates how complementary nucleotides available in the cell pair with those of each old strand before they are joined together to form a daughter strand.
20 Mutation A change in the nucleotide sequence of a DNA molecule. DNA proofreading and repair prevent many replication errors.Unrepaired mutations that affect genes that control cell division can cause diseases such as cancer.
21 Protein Synthesis10.4The Central Dogma: the flow of genetic information from DNA to RNA to Protein
22 Protein Synthesis 2 Parts Transcription – makes a RNA molecule complementary to a portion of DNA.Translation – occurs when the sequences of bases of mRNA directs the sequence of amino acids in a polypeptide.
23 RNA Ribonucleic Acid 2nd type of nucleic acid Monomer = nucleotide Ribose sugar1 of 4 N basesPhosphate group
24 N-bases: A, G, C, & U Uracil replaces Thymine Base pairing rules: A-U, G-CPurpose: to transfer genetic material from DNA (inside the nucleus) to the site of protein synthesis (in the cytoplasm)
25 How does RNA differ from DNA? Different sugars (deoxyribose vs. ribose)Different N-bases (thymine vs. uracil)Different shapes (double helix vs. single strand)
26 Types of RNA: Messenger RNA (mRNA): Transfer RNA (tRNA): Carries genetic info from the nucleus to the cytoplasmTransfer RNA (tRNA):Carries specific amino acids to the ribosome to build the proteinRibosomal RNA (rRNA):Major component of the ribosome organelleSite of protein synthesisMost abundant type of RNA
28 Notebook Quiz 1. Outline the flow of genetic material in cells. List the 3 parts of a nucleotide.What role does helicase and DNA polymerase play in DNA replication?a. Write the complementary strand of DNA to the DNA template below…b. Write the complementary strand of RNA to the DNA template below…G A T T A C A T C C G A C T A C5. What is the purpose of RNA?6. List 2 differences between DNA and RNA (be specific).
29 How is RNA made? Transcription The process by which RNA is copied from DNA in the nucleus
30 Steps of Transcription: RNA polymerase binds to the promoter section of DNADNA unwinds and separatesRNA polymerase adds nucleotides complimentary to the DNA template strandProcess ends once RNA polymerase reaches the termination signal on the DNA
31 Definitions:RNA polymerase: enzyme use to make an RNA polymer from DNAPromoter: Starting point on DNADNA template: Strand of DNA that RNA is complementary to (create from)Termination signal: Ending point on DNA
36 Products of Transcription: mRNA, tRNA, & rRNAAll products move out of the nucleus and go into the cytoplasm to be used in protein synthesisDNA RNAmRNAtRNArRNA
37 Proteins carry out the genetic instruction in DNA Protein Synthesis:The making of proteins at the ribosomeThe amount and kind of proteins produced in a cell determine its structure & functionProteins carry out the genetic instruction in DNA
38 Protein Review: Monomer = amino acids 20 different types Linked together by peptide bondsSequence of amino acids determines the proteins structure and function
39 The Genetic Code:The correlation between nucleotide sequence (DNA or RNA) and amino acid sequence (protein)Codons: combination of 3 mRNA nucleotides that code for a specific amino acid
41 Types of codons: 64 codons code for 20 amino acids Thus more than one codon codes for an AAStart codon: (AUG) starts the process of translationStop codons: (UAA, UAG, UGA) ends the process of translation
44 Translation:The process of assembling polypeptides (proteins) from nucleotide sequence in mRNA“Translating” from one language (nucleotides) into another language (amino acids)
45 Steps of TranslationInitiation: mRNA binds to the ribosome and the tRNA carrying methionine binds to the start codonElongation: as mRNA codons move through the ribosome, tRNA’s add specific amino acids to the growing polypeptide chainTermination and Disassebly: the process continues until a stop codon is reached and the newly made protein is released
52 So what is the Central Dogma? The flow from DNA to RNA to Protein
53 Notebook Quiz What type of RNA is pictured here? What is its function? List the 4 bases in RNA?What is the function of mRNA?Define translation.Where are proteins assembled in the cell?Describe the flow of genetic material in the cell. In other words, how do cells make proteins?