Polymers

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Polymers

• DNA Structure and Function

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History of DNA

• Scientists were aware that DNA had a sugar
  phosphate background and had bases A, T, G and C
  but were not sure about the actual shape of DNA.
  
• Wilkins and Franklin used X-ray crystallography
  to create images of DNAs structure.
• Watson discovered that the base pairs A to T were
  exactly as long as G to C. Causing each rung to
  be of equal length

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Founders

• Now that they had the shape helical or twisted
  ladder and the base pairing rule, they could
  share with the scientific community the shape of
  DNA.
• NOBEL PRIZE awarded to Watson and Crick shared
  with Wilkins and Franklin for discovering the
  shape of DNA.

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Nucleic acids

• DNA Deoxyribonucleic Acid a simple polymer
• the molecule of heredity.
• DNA Animation
• http//www.youtube.com/watch?vl-hrLs03KjYfeature
  related

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Job of DNA

• Stores information on how to make proteins the
  buildingblocks of living organisms

Hydrogen Bonds
phosphate
Sugar
SHAPE Double helix
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What is a Monomer

• the simple building blocks used to hook together
  to build long, complex polymers
• ex. Keratin (protein in hair), Nylon, plastics,

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What is a Nucleotide?
The monomers that builds up the DNA polymers
What are the components found in nucleotides?

• Sugar
• Phosphates
• Bases

A Nucleotide
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Sugar Phosphate

• C6H12O6 Found on DNA

Sides of the ladder Backbone of DNA
Ribose
Deoxyribose
DNA is found in the Nucleus
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Types of Bases
Adenine Uracil only in RNA

• Guanine Thymine Cytosine

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Purines and Pyrimidines
Purines- double ringed Pyrimidines single ringed
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Which Bases Pair Together

• A T
• C G
• Why do they pair together?

Hydrogen bonds A T has two bonds G C has
three bonds
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Anti-parallel-What does it mean?
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What are Genes?

• Long stretches of DNA that are recipes for how
  to build a specific protein.
• For example the gene for Kertain is a stretch
  of DNA with instructions for building a Keratin
  molecule

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Summary Flow Chart
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How are genes, proteins, traits, DNA and
chromosomes related?

• traits are the result of proteins
• Proteins are determined by a stretch of DNA
  called a gene.
• Genes are stretches of DNA on a chromosome.
• DNA codes for the proteins that make up traits

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What could happen if genes had the wrong sequence
of nucleotides?

• Incorrect proteins could be made. This could
  lead to disease, spontaneous abortion, cancer or
  death.

Called a Mutation
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• When does DNA remake itself?
• Interphase
• 3 parts to Interphase
• G1 cell carries out
• normal functions
• S DNA is copied
• G2 Cell carries out
• normal functions

DNA Synthesis
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• What must be present for DNA to remake itself?
• Original
• Ink and paper
• Photocopier

Original DNA
Nucleotide
DNA Polymerase
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• Original Strand
• The original strand is used as a template
• Example

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• A nucleotide is the sugar, phosphate and base.
• Where do the free nucleotides come from?
• From the food that we eat
• Adenine, Thymine, Cytosine, Guanine

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• What is an enzyme?
• An enzyme is a protein
• Cellular Machine that can build up or tear
  apart molecules.

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DNA replication wrap up

• http//www.youtube.com/watch?vhfZ8o9D1tus

• Template (original) Strand original strand
  used to tell what nucleotide to add
• b. Newly Synthesized (copy) Strand just being
  built, a copy of the original strand

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• What happens during DNA replication?
• a. - DNA unzips
• Helicase unwinds DNA double helix breaks
  hydrogen bonds

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b. - DNA polymerase attaches to DNA
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• c. DNA polymerase copies DNA
• Free nucleotides find their compliments on each
  side of the DNA strand

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New bases keep attaching until two identical
molecules of DNA are created. This is called
semi-conservative replication.
THE RESULT 2 new DNA molecules, each is ½ old
strand, ½ new strand Mitosis then follows where
each cell gets copy
1
2
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A T T A G C A T C G
A T G A C
A T G A C
T A C T G
- T - A - C - T - G

• A T
• T A
• G C
• A T
• C - G

• DNA unzips
• Hydrogen bonds broken

• DNA is copied
• Free nucleotides attached

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A T T A G C A T C G
A T G A C
A T G A C
T A C T G
- T - A - C - T - G

• A T
• T A
• G C
• A T
• C - G

Template Strand
Template Strand

• Old DNA strand

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A T T A G C A T C G
A T G A C
A T G A C
T A C T G
- T - A - C - T - G

• A T
• T A
• G C
• A T
• C - G

Copy Strands

• New DNA Strand

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(No Transcript)
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• Reads in an anti-parallel direction when bringing
  in free nucleotides
• EX

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• http//www.dnalc.org/view/15509-DNA-replication-an
  imation-3D-animation-with-basic-narration.html
• Video
• http//www.youtube.com/watch?vzdDkiRw1PdUfeature
  related
• Song http//www.youtube.com/watch?vdIZpb93NYlw
  featurerelated

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ANIMATIONS
http//www.contexo.info/DNA_Basics/DNA20Replicati
on.htm
http//www.teachersdomain.org/sci/life/gen/mechdna
/index.html
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Proteins

• Subunits of life
• Monomers Amino Acids

Polymers many A.A. joined together to form a
polypeptide chain
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To Recognize

• Amino group NH2 or NH (circle in green)
• Carboxyl COOH or CO (circle in red)

These are the side chains or R groups makes
each amino acid different from one another
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• Proteins long chain of amino acids bonded
  together
• Peptide bond (Circle in figure below)

Peptide Bond
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Organisms build proteins from 20 amino acids

• Flip and look at the page with our 20 amino
  acids.
• Dont need to memorize these, but noticeALL
  have an NH2 and a COOH group.

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Why are protein important?

• Enzymes speed up biological reactions
• Antibodies immune system
• Channels allow ions through cell membrane by
  creating channels

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Types of Proteins

• Enzymatic (speed up/control chemical reactions)
• Catalase located in plants, animals and aerobic
  bacteria to break down hydrogen peroxide
  (otherwise harmful, toxic) into water and oxygen

H2O2 ? H2O O2
H2O2 poison builds up as we digest food

• In the liver H2O2 is changed to water and oxygen
  by Catalase

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• Rhodopsin a protein in the membrane in the
  photoreceptor cell in the retina in the eye.
  This part changes shape when light hits it and
  leads to a nerve impulse to being transmitted to
  the brain

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• Structural (our building blocks) actin and myosin
  work together to help the muscle cells relax and
  contract

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• Oxygen Carriers Hemoglobin is two proteins
  (alpha and beta) are in red blood cells that
  stick together They carry oxygen

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• Hormones (send signals) Insulin- binds and
  changes shape of receptor to form a tunnel to
  allow entry of molecules such as glucose into the
  cells.

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Now that you understand

• What determines the role or function of a
  protein?
• Shape
• What determines the shape of a protein?
• Function