DNA

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DNA
DNA
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DNA

• located in the nucleus
• Function Carry genetic material
• Many People contributed to the discovery of DNA.

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People Who Discovered DNA

• 1928 Frederick Griffith - DNA carrier of
  genetic info
• 1944 Avery Genes composed of DNA
• 1952 Hershey and Chase genetic material
  DNA, not protein

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People Who Discovered DNA

• 1952 Rosalind Franklin DNA twisted
• 1952 Edwin Chargraff - A T C G
  Chargraffs Rule
• 1953 Watson and Crick Discovered structure of
  DNA we know today

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What we Know Now........
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Shape of DNA

• Double Helix.
• -Twisted ladder or spiral staircase
• Two stranded
• Held together by hydrogen bonds
• Made of four Nucleotides

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Structure of DNA

• Remember
• DNA is a nucleic acid.
• Nucleic acids are made of nucleotides

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Nucleotides

• DNA long chain of nucleotides
• 4 that make up DNA
• Have 3 parts a sugar molecule (deoxyribose), a
  phosphate group, and a nitrogenous base

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4 NitrogenousBases

• Adenine
• Guanine
• Cytosine
• Thymine

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Sides of the Ladder are made up of sugar and
phosphate.
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Adenine always pairs with ThymineCytosine always
pairs with Guanine
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Would Thymine be able to pair up with Guanine?
NO!!
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DNA REPLICATION
DNA Replication
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DNA Replication

• Before mitosis, the DNA must be replicated
  (Copied) exactly.
• Each strand can be used to make the other strand.
• Many enzymes are involved.

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Chromosome Structure

• DNA is packed very tightly as chromosomes in the
  nucleus.
• Human nucleus has 1 meter of DNA!
• Smallest human chromosome has 30 million base
  pairs.

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• Chromosome
• Structure
• A chromosome has DNA and protein-chromatin.
• Tiny sections of DNA are called genes

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• Steps
• parent/original strands are unwound with the help
  of DNA helicases (enzymes).
• Replication Bubble

Semi-conservative replication
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Replpication Bubbles
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• Steps
• 2. DNA polymerase attached new nucleotides to the
  parent strands

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DNA replication website
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• How a protein is made
• Transcription
• Translation

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• DNA codes for all of the cell proteins.

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DNA Transcription
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• Overview
• DNA is located in the Nucleus
• Proteins are made on the ribosomes.
• DNA makes a copy (send a message) called mRNA

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Two Steps of Protein Synthesis

• 2. Translation

• 1. Transcription

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• Transcription
• a copy of the DNA is madethe copy is called
  messenger RNA or mRNA.
• The mRNA takes the code to the ribosome.

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DNA vs. RNA

• Single Stranded
• AGUC
• Ribose
• YES!

• Double Stranded
• AGTC
• Deoxyribose
• NEVER!

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DNA Transcription

• During transcription the DNA unzipped and RNA
  nucleotide are paired up with the DNA bases.
• Website

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DNA Translation
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• Once the mRNA copy is made, it can go to the
  ribosome to be translated.

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• Remember.Proteins are made out of amino acids.
• There are 20 different amino acids.
• 3 bases code for each amino acid codon.

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How you figure out which codon is coding for
which amino acid
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• Once the mRNA gets to the ribosome, the protein
  can be assembled.
• Transfer RNA brings the amino acids to the
  ribosome.
• Website

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• The three letter code on the mRNA is called a
  codon.
• The three letter code on the tRNA that is matched
  up with the mRNA is called an anticodon.

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Review Clip
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Mutations
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Mutations

• A sudden change in the genetic code is called a
  mutation.
• Most mutations have little or no effect on the
  organism.
• Mutations can be spontaneous or may be caused by
  environmental factors called mutagens.

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Mutations in DNA usually occur through one of two
processes

• 1- DNA damage from environmental agents such as
  ultraviolet light (sunshine), nuclear radiation
  or certain chemicals.
• 2- Errors that occur when a cell replicates its
  DNA in preparation for cell division.

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• Types of Mutations

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• Point mutation
• -a simple change in a single base of the gene
  sequence
• 3 Types
• Point
• Insertion
• Deletion

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• Frame-shift Mutations
• In a frame-shift mutation, one or more bases are
  deleted or inserted, the equivalent of adding or
  removing letters in a sentence.

Original THE CAT ATE THE RAT Deletion THE CAT
ATE THE RAT THE CTA TET HER AT Insertion THE CAT
ATE THE RAT THE CAT ATT ETH ERA T
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DNA MutationsHarmful, Helpful, Neutral

• Substitutions
• Frameshift
• Deletions
• Insertions
• Causes
• Mutagens
• UV light
• Radiation
• Chemicals (ex substances in tobacco products)
• Replication errors

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Which of the following is the correct
base-pairing rule for DNA? A A-U C-G B A-G
T-C C A-T G-C D A-C T-G
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• DNA TECHNOLOGY

industry
DNA fingerprinting
agriculture
medicine
genetic recombination.
forensics
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DNA Fingerprinting How they identify criminals
and do paternity tests (i.e. Who is my Babys
Daddy?)
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• How DNA Fingerprinting works
• Scientist cut up DNA into pieces using enzymes
• Then load the pieces into a gel.
• Electricity is run through the gel.
• The pieces of DNA move to the other end of the
  gel.
• Smaller pieces move farther.

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Who doesnt belong?
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• Recombinant DNA
• is a form of artificial DNA where DNA combined
  that would not normally be combined.
• They cut, splice together, and insert the
  modified DNA molecules from different species
  into bacteria or another type of cell that
  rapidly replicates and divides.
• The cells copy the foreign DNA right along with
  their own DNA.
• Example goldfish have genes for fluorescent
  proteins that have been inserted

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Genetic Engineering

• the manipulation of an organisms genes
• applications in medicine and the environment,
  industry, and agriculture.
• Sheep are used in the production of alpha-1
  antitrypsin, which is used in the treatment of
  emphysema.
• Goats are also producing the CFTR protein used in
  the treatment of cystic fibrosis.
• Crops are being devised that have natural insect
  repellants

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Genetic Engineering Example In the plant world,
the buds of cotton plants are vulnerable to worm
attacks. The buds of a modified cotton plant
resist these worms, resulting in increased cotton
production. These gene insertions are
ecologically safer than pesticides. They affect
only the targeted pest.

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• Scientists today have developed genetically
  altered bacteria.
• Among them are strains of bacteria that
• eat up oil spills
• manufacture alcohol and other chemicals
• process minerals.
• There is concern about possible risks to the
  environment and the general population as
  genetically engineered bacteria are introduced.

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