DNA

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DNA
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Contents of the Nucleus
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DNA vocab

• Deoxyribonucleic acid
• Chromosomes
• Chromatin
• Genes
• Genome

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DNA Structure

• What is the structure called?
• Who received the Nobel Prize for working out the
  molecular structure?

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Building blocks of DNA

• What are the building blocks of DNA? (4 types)
• What are the building blocks made of? (3 parts)

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Polymerization of Nucleotides
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• How do they fit together?
• POLYMERIZATION
• rungs of the ladder
• sides

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Try replicating this single strand of DNA
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DNA Replication 3 Stages - Figure 10-9 - page
187
replication - it does have primerase and
polymerase 1
DNA replication animation- v. realistic but hard
to follow

• 1. UnwindingDNA helicase unwinds and separates
  the two strands of the molecule, exposing the
  bases. This is called the Replication Fork

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2. Formation of the Complementary Strand

• - the parental DNA strands act as a template
• - DNA polymerase attaches to the opened strands
  (one on each side)

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• - it reads the parental DNA strand and attaches
  the appropriate nucleotide to the template A to
  T, G to C (and vise versa)

DNA polymerase
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• - it also connects the sugars and phosphate sides
  of the new strand using dehydration synthesis
  reactions.

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• - DNA polymerase can only travel in one direction
  - from 3 to 5 , therefore, the 2 polymerases
  will travel in opposite directions in the
  replication forks

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The pieces are joined together by DNA ligase

• As the two DNA polymerases move along the DNA
  molecule, ONE will be following the DNA helicase,
  while the other one will be going in the opposite
  direction.

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• - the DNA polymerase that follows the helicase is
  on the LEADING STRAND
• - the other polymerase is going to run into the
  end of the replication fork (where the helicase
  started to open the DNA helix)
• - it must detach at that point.

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• - a new polymerase will attach further up the
  LAGGING STRAND and synthesis a new daughter
  strand up to the point were the first polymerase
  began, and then IT will detach

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• - this process continues in steps until all of
  the lagging strand is replicated

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• - every time the polymerases detach, they leave a
  gap in the sugar-phosphate back-bone
• - DNA ligase will travel along the newly
  synthesized strands, locate the gaps, and make
  the necessary connections to fill them.

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• Finally, both the leading strand and the lagging
  strands are proof-read by specific enzymes to
  ensure that the replication was accurate. ( if it
  wasnt corrected, it would be called a MUTATION.)

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• What is the significance of the order of the
  nitrogenous bases?

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Protein Synthesis

• DNA - a ____________ for making proteins.

BLUEPRINT
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A 2 Step Process

• 1. Transcription the information is copied form
  the DNA molecule to a mRNA molecule

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Try Transcribing this piece of DNA into mRNA
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• 2. Translation the information in the mRNA is
  read in the ribosome and translated by a tRNA
  to make a protein.

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Breaking THE CODE DNA Molecules can be thought
of as a type of sentence. - the bases,
(A,T,G,C) make up the letters - these letters
are arranged into words of three
letters -called triplets - the triplets each
have a specific meaning - they code of a
specific amino acid
THE CAT ATE THE RAT
AUG CCG GCA AAG UAG
Met pro ala lys stop
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The Code

• How do you follow the mRNA code?

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• http//www.youtube.com/watch?vNJxobgkPEAomodere
  latedsearch

Protein synthesis video
Youtube videos - protein synthesis
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• Therefore, the DNA molecule simply tells the cell
  the order of amino acids necessary to make
  proteins.

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NucleicAcids Material DNA vs RNA - compare and
contrast.
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• RNA an intermediate between DNA and
  ribosomes
• The same as DNA except
• the sugar is RIBOSE instead of DEOXYRIBOSE
  
• RNA is SINGLE-stranded
• the base THYMINE is replaced by URACIL.

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The 3types of RNA are all created the same way
by TRANSCRIPTION of the DNA molecule.

• 3 types of RNA
• 1. RiBOSOMAL together with some proteins, they
  make up the structure of RIBOSOMES

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• 2. MESSENGER used to deliver the instructions
  from the DNA to the RIBOSOMES for protein
  synthesis

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• 3. TRANSFER reads the instructions and deliver
  the appropriate AMINO ACID to the ribosome.

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• Why doesnt the mRNA just stay inside the nucleus?

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• DNA in the nucleus is safe
• DNA in the cytoplasm can be destroyed

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Try DECODING this piece of DNA Code
DNA T A C G G A C A G T A A A T T
mRNA
Amino acids
DNA T A C G G A C A G T A A A T T
mRNA A U G C C U G U C A U U U A A
Amino acids Methi-onine Methi-onine Methi-onine proline proline proline valine valine valine isoleucine isoleucine isoleucine stop stop stop
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• Great video on a cells life functions
• http//www.studiodaily.com/main/searchlist/6850.ht
  ml
• Here is the explanation of what is happening
• http//sparkleberrysprings.com/innerlifeofcell.htm
  l
• Protein Production

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Protein Structure
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RecapGenes

• WHAT are they?
• WHERE are they?
• How many genes do we have?
• WHY are we storing the information for PROTEINS???

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Preview Enzymes

• WHAT are they?
• What do they do?
• Why do our DNA molecules store the instructions
  to make them?

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One Gene One Protein?

• Human genome approximately 25,000 genes
• Number of proteins humans make is approximately
  90,000.
• NOT SURE HOW THIS CAN BE!

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Mutations - Define
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Types of Mutations
Example Deletion The result can be a completely
non-functional proteindoesnt make sense. i.e.
--- THE CAT ATE THE RAT--- If you delete
a base (letter) C ---THE ATA TET HER AT-----

• Deletion
• Addition
• Substitution
• Positive
• Neutral
• Negative
• Mutagens

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• Another example
• Original message
• THE BIG DOG BIT TED AND RAN OFF ---
  ---
• ADDITION/FRAMESHIFT
• THE BIG FDO GBI TTE DAN DRA NOF
  F--
• Changing the sequence