DNA (Deoxyribose Nucleic Acid)

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genetics
http//www.youtube.com/watch?vB_PQ8qYtUL0
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DNA

• Deoxyribonucleic acid
• Located in the nucleus
• Instructions for how to make proteins

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Watson Crick
Determined the shape/structure of DNA in 1953
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Rosalind Franklin

• X-ray Crystallography

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Structure

• Scientists James Watson and Francis Crick
  developed a three dimensional model of DNA
• This model of DNA consisted of two strands which
  were wound around each other like a twisted
  ladder. This structure is known as a double helix

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Every living thing has DNA. That means that
you have something in common with a zebra, a
tree, a mushroom and a beetle!!!!
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• Three critical things genes need to do
• 1.) genes need to carry information from one
  generation to the next
• 2.) put that information to work by determining
  the heritable characteristics of organisms
• 3.) genes need to be easily copied

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DNA is like a fingerprint because everyones is a
little different!
You can tell people apart by their
fingerprints and their DNA!
How would the police look at DNA to figure out
who committed a crime?
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PUT ON YOUR SCIENCE EYES!
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Which statement reflects the correct
relationship between the nucleus, the cell,
chromosomes, and DNA?
A. DNA is made of chromosomes that are contained inside the nucleus of a cell. C. DNA makes up the membrane surrounding a cells nucleus.
B. A cells nucleus contains the chromosomes which are made of DNA. D. Chromosomes make up DNA that is contained outside the cells nucleus in the cytoplasm.
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SO WHAT IS DNA?PLEASE COPY THIS CHART INTO YOUR
NOTES
DNA
NUCLEOTIDE

4 BASES

DOUBLE HELIX
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DNA stands forD DeoxyriboseN NucleicA Acid
DNA is too small to see, but under a microscope
it looks like a twisted up ladder!
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What is DNA? DeoxyriboNucleic Acid

• A molecule of nucleic acids that carries genetic
  information.
• 2 strands twisted around each other called a
  double helix (twisted ladder)
• Each strand is made of linked nucleotides.

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• Made up of nucleotides
• sugar
• phosphate
• nitrogen base

Nucleotide
Hydrogen bonds
Sugar-phosphate backbone
Key Adenine (A) Thymine (T) Cytosine
(C) Guanine (G)
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What is a Nucleotide?

• A subunit of DNA made of 3 parts
• 5-carbon sugar (deoxyribose)
• phosphate group
• nitrogenous base (there are 4)

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DRAW THIS NUCLEOTIDE
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 Structure of DNA
Nucleotide
Hydrogen bonds
Sugar-phosphate backbone
Key Adenine (A) Thymine (T) Cytosine (C) Guanine
(G)
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• The nucleotides are made up of
• deoxyribose(sugar)
• phosphate group
• nitrogen bases-4 types 1. Adenine- A 2.
  Guanine-G 3. Cytosine- C 4. Thymine-T

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WHAT ARE THE 4 BASES?
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What is the structure of DNA?

• The sides (backbone) are made of sugars and
  phosphates held together by a strong chemical
  bond.
• The rungs (steps) are paired nitrogenous bases
  held together by a weak hydrogen bond.

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How are the Bases paired?

• Adenine pairs w/Thymine (A-T)
• Guanine always pairs w/Cytosine (G-C)
• This is called complementary pairing. They fit
  like puzzle pieces.
• Allows the DNA to be replicated (copied).

G
C
T
A
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2-stranded DNA
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THE DOUBLE HELIX
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bases
sugar-phosphate chain
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TIME TO MAKE A DNA MODEL!!!
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• Left Hand Assignment DNA Structure
• Glue the DNA strand and use the following
  instructions to color the double helix. Write and
  answer the questions when you are finished

• DNA Structure Analysis
• The twisted ladder structure of DNA is called a
  ________________.
• The backbone of DNA is made up of
  _______________________.
• The ladder-like rungs of DNA are made up of
  _________________.
• Adenine always pairs up with __________.
• Cytosine always pairs up with _________________.
• A nucleotide is the basic building block of DNA.
  A nucleotide is made up of one ___________, one
  ________, and one___________.

• DNA Coloring Instructions
• Color the deoxyribose sugars green.
• Leave the phosphate groups white.
• Color the nitrogen base adenine orange.
• Color the nitrogen base thymine light blue.
• Color the nitrogen base cytosine red.
• Color the nitrogen base guanine yellow.