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DNA
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DNA
CLIP
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DNA Vocabulary quizzes
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• Quiz2 (Thur)
• Messenger RNA
• Transfer RNA
• Transcription
• Translation
• Codon
• Anti-Codon
• Promoter
• Intron
• Exon
• Genetic Code
• Amino Acid
• Protein
• Polypeptide
• Mutation
• DNA
• RNA

• Quiz 1 (Tue)
• Nucleotide
• Base Pairing
• Transformation
• Deoxyribose
• Double Helix
• Chromatin
• Replication
• DNA Polymerase
• Helicase
• Chromosome
• Complementary
• DNA

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UNIT GOALS
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• Distinguish between DNA and RNA.
• Explain the role of DNA in storing and
  transmitting cellular information.
• Describe the relationships between changes in DNA
  and potential appearance of new traits including
  alterations during replication, insertions,
  deletions, substitutions, mutagenic factors,
  radiation, chemicals.
• Examine the use of DNA technology in forensics,
  medicine and agriculture.

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DNA

• Function Store Transmit genetic information
• Acts as a library or storehouse of informtion.
• DNA is located in the nucleus.

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Discovery of DNA

• Many People contributed to the discovery of DNA.

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Frederick Griffith (Transformation)
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1928

• Experiments with Diplococcus pneumonia
  (bacterium responsible for pneumonia), witnessed
  a transformation.

• These experiments are recognized as the first in
  a series that lead to the conclusion that DNA is
  the carrier of genetic information, the genetic
  material.

DNA is the molecule of inheritance
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Oswald Avery
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1944

• Repeated Griffiths experiment
• Looking for what is being transferred.
• Used enzymes to break up carbohydrates, lipids
  and proteins-transformation still took place.
• Used enzymes to break up DNA-transformation did
  not happen.
• Conclusion DNA is a Nucleic Acid

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Rosalind Franklin Maurice Wilkins
1952

• Used x-ray diffraction to see DNA.
• Conclusions DNA is twisted like a spiral
  staircase

Double helix
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Erwin Chargaff
1952

• Discovered that the
• amount of Adenine amount Thymine
• amount of cytosine amount of guanine.
• True in all organisms tested.
• Called Chargaffs Rule.
• Conclusions
• 1. amt A is to amt of T
• 2. amt C is to amt of G

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Watson and Crick
1953

• Put it all together
• Developed the structure of DNA that we know
  today.
• Conclusions Described the complete structure of
  DNA.

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CLIP
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What we Know Now........
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Structure of DNA

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

• Phosphate
• Base ( Nitrogen)
• Sugar

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Structure of DNA

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

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Nucleotides
Structure of DNA

• Long chain of Nucleotides
• There are four nucleotide that make up DNA
• Each nucleotide has three parts (PBS)

• The sugar is Deoxyribose
• There are four bases
• Adenine, Guanine, Cytosine, Thymine

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4 Bases
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• Adenine
• Guanine
• Cytosine
• Thymine

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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CLIP
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The sequence of nucleotides forms the unique
genetic information of an organism.
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Flashback
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• Before a cell divides it needs to make a copy of
  its DNA.
• (Remember S-phase?)
• How does it do that?

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DNA REPLICATION
DNA has the unique ability to make an exact copy
of itself in a process called Replication.
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Chromosome Structure
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• DNA is packed very tightly in the nucleus.
• Human nucleus has 1 meter of DNA!
• Smallest human chromosome has 30 million base
  pairs.

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

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DNA Replication
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• Before Cell Division, the DNA must be replicated
  exactly.
• Each strand is used to make a new strand.

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• Many enzymes are involved.

Complementary Strands
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• Steps
• The two parent strands are unwound and unzipped
  with the help of DNA helicases.
• Replication Bubble

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Replpication Bubbles
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• Steps
• 2. DNA polymerase attaches new nucleotides (base
  paring) to the parent strands
• Each new strand formed is a complement of one
  of the original, or parent, strands.

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• This process will continue until the entire
  molecule has been unzipped and replicated.

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DNA replication website
Each new strand formed is a complement of one of
the original, or parent strands.
Semi-conservative replication
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• When all of the DNA in the chromosomes of the
  cell have been copied by replication, there are
  now two copies of the genetic information that
  will be passed on to new cells during mitosis or
  to new generations through the process of meiosis.

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Review Clip
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DNA stores the information needed by a ribosome
to make a protein.

• How does the ribosome get the information?
• How does the ribosome read the information?
• How does it make the protein?

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• How a protein is made.
• PROTEIN SYNTHESIS

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• DNA contains the code for all of the cell
  proteins.

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• Flashback
• 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

LOCATIONS
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Where do the steps take place?
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• 1. Transcription Nucleus
• During transcription a backwards 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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• 1. Transcription Nucleus
• The section that is copied is called a gene.
• The gene contains the code for a protein.

backwards copy
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DNA vs. RNA

• Double Stranded
• AGTC
• Deoxyribose
• NEVER!

• Single Stranded
• AGUC
• Ribose
• YES!

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2. Translation Cytoplasm

• Once the mRNA copy is made, it can go to the
  ribosome and be used to make a protein
  (translated)

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2. Translation Cytoplasm

• To have the correct translation of the code, mRNA
  codons must join with the correct anticodon
• of the tRNA.

Ribosome
tRNA anticodon
mRNA codons
The ribosome reads every 3 letters
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2. Translation Cytoplasm

• To have the correct translation of the code, mRNA
  codons must join with the correct anticodon of
  the tRNA.

tRNA brings the amino acids to the ribosomes
tRNA anticodon
mRNA codons
A codon is a group of 3 nitrogenous bases on an
mRNA molecule that carries the code for a
specific amino acid. An anticodon is a set of 3
nitrogenous bases on a tRNA molecule that matches
a codon on an mRNA molecule.
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animation
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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.

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mRNA codons
The Genetic Code
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• Another version of the Genetic Code

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• In summary
• Messenger RNA (mRNA) carries the message of the
  genetic code from the DNA in the nucleus to the
  ribosomes in the cytoplasm.
• At the ribosomes, the mRNA sequence is translated
  into a protein in a process known as translation.
  Transfer RNA (tRNA) transfers the amino acids in
  the cytoplasm to the ribosomes.
• The amino acids are lined up in the coded
  sequence to form a specific protein.

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Review Clip
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Eukaryotic DNA processing
Sometimes the DNA is cut up before it leaves the
nucleus.
Exon - RNA sequences in the primary transcript
that are found in the mRNA Intron - RNA sequences
between exons that are removed by splicing
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EOCT QuestionsWhich of the following shows how
information is transformed to make a protein?A
DNA?RNA?proteinB gene?chromosome?proteinC cell
respiration?ATP?proteinD ATP?amino acid?protein
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• Information on mRNA is used to make a sequence of
  amino acids into a protein by which of the
  following processes?
• A replication
• B translation
• C transcription
• D transference

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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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Mutations
Describe the relationships between changes in DNA
and appearance of new traits
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Mutations
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• Every so often genes do change.
• 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
• UV light
• Radiation
• Free radicals
• Chemicals (ex substances in tobacco products)
• 2- Errors that occur when a cell replicates its
  DNA in preparation for cell division.
• Spontaneous
• An enzyme may fix the wrong base.

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• Types of Mutations

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• Base pair substitutions
• (Aka Point mutation)
• Frameshift mutation
• deletions or insertions

CLIP
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Base pair substitutions
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Point mutation

• The substitution of one amino acid for another
  during protein synthesis.
• Can be harmless or it change the entire protein.

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Base pair substitutions
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Point mutation

• The inherited disorder sickle-cell anemia is
  caused by a this type of mutation.

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Frameshift mutations-deletions or insertions
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• When one or more base pairs are inserted into a
  DNA molecule or deleted from it.
• Causes a reading frame shift during translation.

CLIP
ACTIVITY
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• DNA TECHNOLOGY

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industry
DNA fingerprinting
agriculture
medicine
forensics
genetic recombination.
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Forensics
There are many uses for DNA technology. Police
labs use DNA technology to identify people
through a process known as DNA fingerprinting.
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• How to make a DNA fingerprint

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• Scientist cut up DNA into pieces using enzymes-
  Restriction Enzymes
• Then load the pieces into a well.
• Electricity is run through the gel.
• The pieces of DNA move to the other end of the
  gel with the charge.
• Smaller pieces move farther.

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Who doesnt belong?
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Who done it?

• A blood stain was found at a crime scene. Who is
  the perpetrator of the crime?

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• Researchers use recombinant DNA technology to
  analyze genetic changes.
• They cut, splice together, 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.
• An example of this is the gene for human insulin
  inserted into a bacterium. This is how human
  insulin is mass produced.

medicine
Click on Picture
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• Restriction Enzyme animation
• Animation 2
• Cloning a Gene

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Bacteria DNA that has DNA from another organism
spliced in to it.
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• 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.

agriculture
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Called Transgenic Organisms
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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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Plant biologists have used DNA technology to
produce plants with many desirable traits. These
include increased disease resistance, herbicide
resistance, and increased nutritional content.
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Golden Rice 23 times more Vitamin A
Called a Transgenic Organism
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Transgenic Organisms
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Transgenic Tobacco, from 1986. This is an
ordinary photographic image of a tobacco plant
engineered to express a firefly gene which
produces luciferase.
CLIP
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Clip

• 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.
• Make human proteins.
• There is concern about possible risks to the
  environment and the general population as
  genetically engineered bacteria are introduced.

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Cloning
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(No Transcript)
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Bill Nye
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