Chapter 12 DNA and RNA

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Chapter 12DNA and RNA

• transformation, bacteriophage, nucleotide, base
  pairing, chromatin, histone, replication, DNA
  polymerase, gene, messenger RNA, ribosomal RNA,
  Transfer RNA, transcription, RNA polymerase,
  promoter, intron, exon, codon, translation,
  anticodon, mutation, point mutation, frameshift
  mutation, polyploidy, adenine, cytosine,
  deletion, guanine, nitrogen base, purine,
  pyrimidine, thymine, uracil

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12-1 DNA
12-1 DNA

• Frederick Griffith 1928 looking at how mice
  react to two
• related pneumonia bacteria
• Experiment
• - Rough bacteria mice live
• - Smooth bacteria mice got pneumonia die
• - Heat-killed smooth bacteria mice live
• - Heat killed smooth rough bacteria mice
  got pneumonia die

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Figure 122 Griffiths Experiment
12-1 DNA
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Figure 122 Griffiths Experiment
12-1 DNA

• Results heat killed smooth bacteria could pass
  on their trait to harmless strain called
  transformation
• Oswald Avery 1944 repeated Griffiths exp.
  and found thatDNA was the transforming factor

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12-1 DNA

• Alfred Hershey Martha Chase 1952 worked
  with bacteria and virus to find out if protein
  or DNA held genes
• Virus DNA/RNA surrounded by a protein coat
• Bacteriophage a virus that infects bacteria
• Experiment
• - Radioactive marker attached to protein part of
  bacteriophage infects bacteria marker was
  seen outside of bacteria
• - Radioactive marker to DNAinfection marker
  was seen inside bacteria

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Figure 124 Hershey-Chase Experiment
12-1 DNA

• Results genetic material of bacteriophage was
  DNA

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Components and Structure of DNA
12-1 DNA

• Nucleotides units (monomers) that make up DNA
  molecule
• Made of 3 parts
• - deoxyribose a 5-carbon sugar
• - a phosphate group
• - a nitrogenous base

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12-1 DNA

• 4 possible nitrogenous bases
• - purines Adenine or Guanine
• - pyrimidines Cytosine or Thymine

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• Erwin Chargaff studied amounts of nitrogenous
  bases in DNA
• guanine equal to cytosine
• adenine equal to thymine
• also known as base pairing rule AT and CG

12-1 DNA
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12-1 DNA

• Rosalind Franklin 1952 X-ray diffraction to
  get pattern from structure of DNA
• James Watson Francis Crick 1953 published
  model and paper on DNA structure as a double
  helix
• double helix is similar to a twisted ladder or
  spiral staircase
• - deoxyribose and phosphate make up
  sides/backbone
• - nitrogenous base makes up stairs/rungs

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12-2 Chromosomes and DNA Replication

• Prokaryotes generally circular strand of DNA in
  cytoplasm
• Eukaryotes multiple molecules of DNA in nucleus

Chromosome
E. coli bacterium
Bases on the chromosome
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12-2 Chromosomes and DNA Replication

• Chromosome structure
• Chromatin DNA that is tightly packed around
  proteins called histones
• - during cell division, chromatin form packed
  chromosomes

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DNA Replication
12-2 Chromosomes and DNA Replication

• Replication process of copying DNA
• - occurs during S phase of Interphase
• - process
• 1. DNA is separated into two strands by an
  enzyme
• 2. free nucleotides are added by DNA polymerase
  according to base pairing rule

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DNA Replication
12-2 Chromosomes and DNA Replication
Nitrogenous bases
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12-3 RNA and Protein Synthesis
12-3 RNA and Protein Synthesis

• RNA structure
• Has ribose as a sugar instead of deoxyribose
• Is generally single-stranded
• Has uracil instead of thymine

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12-3 RNA and Protein Synthesis

• Types of RNA
• All types control protein synthesis in a cell
• 3 main types
• - mRNA messenger RNA copies of instructions
  from DNA
• - rRNA ribosomal RNA part of ribosomes
• - tRNA transfer RNA transfers amino acids to
  ribosome

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12-3 RNA and Protein Synthesis
RNA
can be
also called
which functions to
also called
also called
which functions to
which functions to
from
to
to make up
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RNA Decoding Chart
12-3 RNA and Protein Synthesis
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Figure 1214 Transcription
12-3 RNA and Protein Synthesis

• Transcription process of copying part of
  nucleotide Sequence of DNA into a complementary
  strand of RNA
• run by enzyme called RNA polymerase

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• The Genetic Code
• Proteins are chains of amino acids
• - 20 different amino acids
• - the order or sequence of amino acids
  determines properties of the protein
• - codon 3 consecutive nucleotides that specify
  a single amino acid
• - one amino acid can have multiple codons

12-3 RNA and Protein Synthesis
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Translation
12-3 RNA and Protein Synthesis

• Translation the decoding of an mRNA message
  into a polypeptide chain (protein)
• Occurs on ribosomes

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12-3 RNA and Protein Synthesis

• Process
• - mRNA binds to ribosome
• - tRNA brings appropriate amino acid to ribosome
  tRNA has anticodon that is complementary to
  codon on mRNA begins with specific start codon -
  AUG
• - peptide bonds are made between amino acids
• - assembly line continues until a stop codon

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12-3 RNA and Protein Synthesis

• Why bother?
• Transcription and translation keep master plans
  (DNA) safe in the nucleus, while blueprints (RNA)
  are sent to the worksite (ribosomes)
• Proteins are needed to act as enzymes that
  produces the color of your skin, the type of
  blood cell, the rate of growth

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12-4 Mutations
12-4 Mutations

• Mutation a change in the genetic material
• Point mutations change in one or a few
  nucleotides
• Frameshift mutations adding or deleting a
  nucleotide very disruptive

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Chromosomal Mutations
12-4 Mutations

• Chromosomal mutations change in the number or
  structure of chromosomes.
• - Deletion loss of all or part of a chromosome
• - Duplication produce extra copies of parts of
  chromosome

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12-4 Mutations

• - Inversion reverse direction of parts of
  chromosome
• - Translocation part of one chromosome breaks
  and attaches to another
• - Polyploidy an organism has an extra sets of
  chromosomes