DNA Lifes Code

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DNA Lifes Code

• Chapter 28

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DNA/RNA Rap

• C to G and G to C
• A to T and T to A
• That is the only way
• When it comes to DNA!

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• C to G and G to C
• A to U and U to A
• That is the only way
• When it comes to RNA!

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DNA

• Stands for deoxyribonucleic acid
• Double helix shape like a twisted ladder
• Made of nucleotides

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• Watson, Crick, Franklin scientists who figured
  out shape and structure of DNA

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Nucleotide

• Sugar Deoxyribose
• Phosphate group
• Nitrogen base

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(No Transcript)
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• There are 4 different kinds of nitrogen bases
• Adenine (A)
• Guanine (G)
• Cytosine (C)
• Thymine (T)

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Complementary Base Pairing

• A?T, G ?C
• A will only fit with T
• G will only fit with C

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DNA and Chromosomes

• DNA makes up the chromosomes found in the nucleus
• Genes are small sections of chromosomes
• Genes are short pieces of DNA
• Each gene is made of a number of nitrogen bases
• Genes determine your traits

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Proof That DNA Controls TraitsExperiment A

• Living harmless bacteria injected into mice
• Mice live
• Harmless bacteria cannot kill mice

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Experiment B

• Living pneumonia bacteria injected into mice
• Mice die
• Harmful bacteria can kill mice

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Experiment C

• Dead pneumonia bacteria injected into mice
• Mice live
• Dead, harmful bacteria cannot kill mice

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Experiment D

• Mixture of living, harmless bacteria and dead
  pneumonia bacteria are injected into mice
• Mice die
• The live harmless bacteria picked up DNA from the
  dead harmful bacteria DNA transformed the
  harmless bacteria into harmful bacteria

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Nucleotides

• DNA with
• Nucleotides

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How DNA Works

• The order of the nitrogen bases determines the
  trait
• A difference in the order of the nitrogen bases
  can cause a genetic disease like sickle cell
  anemia

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• The nitrogen bases in DNA spell out a message
  that is stored in code
• Different orders of bases give different messages

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Making Proteins

• DNA directs protein synthesis in cells
• The DNA cant leave the nucleus
• Proteins are made at the ribosomes
• Messenger RNA transcribes the DNA message and
  carries it from the nucleus to the ribosomes so
  proteins can be synthesized

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• The messenger RNA specifies which amino acids in
  what order are needed to make the protein
• Transfer RNAs pick up the amino acids and bring
  them over to the ribosomes so the protein can be
  assembled

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• Traits show up in a cell because of the kinds of
  proteins being made at the ribosomes
• The genes on the chromosomes sent their messages
  to the ribosomes to have specific traits appear
• The kinds of proteins you have determine what
  traits you have

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How DNA Copies Itself

• DNA unzips
• Loose nucleotides join their complementary bases
  on each single strand of DNA
• Two identical strands are formed

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DNA Replication

• Result 2 exact copies original DNA

DNA Polymerase
Helicase
Replication fork
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DNA coiled into Chromosome
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DNA Replication, Accuracy Repair

• Original A-T-T-C-C-G
• Complement TAAGGC
• Original GCTAAG
• Complement
• Original CTACCA
• Complement
• Original
• Strand A GACCTA
• Strand B

• Mutation
• Point mutation
• Chemicals UV light
• DNA proofreads repairs?1error/ 1Billion

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RNA

• Nucleotide
• Ribose Sugar
• Phosphate Group
• Nitrogen Base
• Adenine (A)
• Guanine (G)
• Cytosine (C)
• Uracil (U) not T
• Single Strand
• 3 Types
• Messenger RNA (mRNA)
• Transfer RNA (tRNA)
• Ribosomal RNA (rRNA)

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3 Types of RNA
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Transcription DNA? RNA

• RNA Polymerase binds to DNA promoter site (begin
  gene)
• Add complementary RNA nucleotides (U?A)

Gene Begins
RNA Polymerase
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Transcription

• DNA termination sequence signals gene end
• RNA Polymersase releases DNA RNA

RNA Polymerase
RNA Strand
DNA Rewinds
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Protein Synthesis Translation

• Proteins polymers
• Polypeptides sequence of amino acids
• Genetic code
• Codon 3 mRNA nucleotides code
• Corresponds with tRNA anticodon amino acid
• START Codon starts translation- 1 codon only?
  AUG
• STOP Codon stops translation- 3 codons? UAA,
  UAG, UGA
• Universal Codon-Amino Acid Code p. 303 (or
  tables)

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mRNA Codon Codon Chart

• AUG?
• Methionine or
• start codon
• AAC?_______

Amino Acids
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tRNA Ribosomes
Amino Acid Attachment Site

• tRNA
• In cytosol
• Binds specific amino acid
• Anticodon
• complement to mRNA codons
• Ribosomes
• Free make proteins for cell
• Attached make proteins for export membrane
• 3 binding sites 1 for mRNA 2 for tRNA

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Overview DNA? RNA? Protein
Transcription
Translation
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Translation mRNA? Protein

• mRNA leaves nucleus
• Ribosome attaches to mRNA start codon
• mRNA codon pairs with tRNA anticodon delivering
  amino acid
• Peptide bond forms between amino acids
• mRNA stop codon signals end of translation
• mRNA released polypeptide complete

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Translation Diagram
Polypeptide Chain
Peptide Bond
Nucleus
Amino Acid
tRNA
Anticodon
Codon
mRNA
Ribosome
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Mutations

• Types
• Germ-cell mutations gametes?affect offspring
• Somatic mutations body cells?affect individual
• Lethal mutations v. beneficial mutations
• 2 categories
• Gene mutation? A.K.A. Point Mutations
• Chromosomal mutation

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Gene Mutations A.K.A. Point Mutations

• Substitution? new codon
• Sickle Cell Anemia substitute A for T

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Gene Mutations (cont)
Deletion

• Nucleotide deletions insertions
• Frame-shift mutations
• Changes amino acid sequence

Insertion
Deletion
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Chromosomal Mutations

• Deletion lose portion
• ?
• Duplication gain extra portion
• ?
• Inversion segment reverses
• ?
• Translocation transfer segment to non-homolgue
• ?
• Nondisjunction gamete gets extra or less
  chromosome (Down Syndrome- Trisomy 21)

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Chromosome Mutations Diagrams
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Genetic Traits Disorders

• Disorders due to nondisjunction
• Nondisjunction gametes have 1 more or less
  chromosome (pairs dont segregate)
• Monosomy 45 chromosomes
• Turners syndrome XO
• Trisomy 47 chromosomes
• Down Syndrome trisomy-21
• Kleinfelters syndrome XXY
• Patau syndrome trisomy-13
• Edwards syndrome trisomy-18

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Chapter 11-2 Cancer

• Tumor uncontrolled cell division
• Benign (cysts, warts)
• Malignant Cancer
• Metastasis cancer cells break off spread
• Kinds
• Carcinomas skin organ linings (breast lung
  CA)
• Sarcomas bone muscle
• Lymphomas tissues that make blood cells
• Leukemia uncontrolled production WBC
• Cancer Effects on Cell Cycle
• Healthy cells stop dividing when crowded
• Cancer cells keep dividing steal blood supply

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Cancer Causes