THE GENETIC MATERIAL

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THE GENETIC MATERIAL

• DNA RNA

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(No Transcript)
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Vocabulary you should know

• DNA (deoxyribonucleic acid) the material that
  contains the information that determines
  inherited characteristics
• Nucleotide in a nucleic-acid chain, a sub-unit
  that consists of a sugar, a phosphate, a
  nitrogenous base

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More Vocab

• Nitrogenous base an organic base that contains
  nitrogen, such as a purine or pyrimidine a
  sub-unit of a nucleotide in DNA or RNA
• Purine a nitrogenous base that has a
  double-ring structure one of two general
  categories of nitrogenous bases found in DNA
  RNA either adenine or guanine

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More Vocab

• Pyrimidinea nitrogenous base that has a
  single-ring structure one of the two general
  categories of nitrogenous bases found in DNA
  RNA thymine, cytosine or uracil
• Base-Pairing Rules the rules stating that
  cytosine pairs w/ guanine adenine pairs w/
  thymine in DNA adenine pairs w/ uracil in RNA

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More Vocab

• Complementary Base Pair the nucleotide bases in
  one strand of DNA or RNA that are paired w/ those
  of another strand adenine pairs w/ thymine or
  uracil, and guanine pairs with cytosine
• Base Sequence the order of nitrogenous bases on
  a chain of DNA
• Double Helix shape of a DNA molecule formed
  when two twisted DNA strands are coiled into a
  springlike structure held together by hydrogen
  bonds b/t the bases

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DNA deoxyribonucleic acid

• The genetic information for an organism
• DNA contains the instructions that cells need to
  make every protein required for essential life
  functions
• Found mostly in the nucleus of cells
• Composed of 100s of 1000s of repeating units of
  nucleotides

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DNA

• Photographed through x-ray crystallography by
  Rosalind Franklin in the 1950s (w/ help from
  Maurice Wilkins)
• 1st model was created by James Watson Francis
  Crick in the 50s, with the use of Franklins
  x-ray crystallography picture

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Rosalind Franklin
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Maurice Wilkins
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James Watson Francis Crick
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DNA

• Made of subunits called nucleotides
• 1 phosphate group
• 1 deoxyribose simple sugar this is what DNA
  is named for
• 1 of 4 nitrogen bases
• Either purines or pyrimidines

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NITROGEN BASES

• Purines double ringed structure
• Adenine (A)
• Guanine (G)

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Nitrogenous Bases

• Pyrimidines single ringed structure
• Thymine (T)
• Cytosine (C)

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STRUCTURE OF DNA

• Shape double helix repeating units of
  nucleotides
• the sequence of nucleotides determines gene
  function

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DOUBLE HELIX

• 2 chains of nucleotide monomers running anti -
  parallel
• Phosphate groups make up the backbone of the
  double helix
• Covalent bonds hold the nucleotides together by
  connecting the deoxyribose of one nucleotide to
  the phosphate group of the adjacent nucleotide

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Double Helix Contd

• The nitrogen bases of the nucleotides pair up to
  link the 2 helixes
• hydrogen bonds b/t the nitrogen bases hold the
  strands of the double helix together

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Double Helix Structure
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Base-Pairing Rules

• Adenine (A)
• Thymine (T)
• are always
• together
• Cytosine (C)
• Guanine (G)
• must then pair together

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DNA Basics Quiz

1. What is DNA?
2. The first person to photograph DNA was
   ____________.
3. The first people to make a model of DNA were
   ________ ______.
4. A strand of DNA is made up of repeating units of
   __________.

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DNA Basics Quiz Contd

1. A nucleotide is composed of 3 parts, name all
   three.
2. List the 4 different nitrogenous bases.
3. Which part of the nucleotide makes up the
   backbone of the strand of DNA?

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DNA Basics Quiz Contd

1. What type of bonds hold the deoxyribose of one
   nucleotide to the phospate of the adjacent one?
2. What type of bonds hold the complementary
   nitrogenous bases together?
3. Out of Adenine, Guanine, Cytosine Thymine, tell
   me the two complementary pairs.

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DNA Technology

• DNA is manipulated for many different reasons
• Crime scene analysis
• Genetic counseling
• Research
• Treatment of disease

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DNA Technology

• DNA ID
• Only identical twins have identical DNA
• Only 10 of the human genome varies between all
  humans
• The 10 that differs falls on the same chromosome
  region so we can isolate this DNA and use it to
  make important discoveries

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Identifying DNA

• Step 1 Copying DNA Polymerase Chain Reaction
• Method of quickly copying DNA from small samples
• Step 2 Cutting DNA Restriction Enzymes
• Restriction enzymes recognize specific short DNA
  sequences cut in or near them
• This isolates the DNA needed for ID

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Identifying DNA contd

• Step 3 Sorting DNA by Size Gel
  Electrophoresis
• Gel electrophoresis separates DNA according to
  size and charge
• Does this by running an electrical current
  through gel that the DNA cut by the restriction
  enzymes has been placed in, - charged pieces
  move to opposite ends
• The resulting pattern is called the DNA
  fingerprint

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Identifying DNA

• Step 4 Comparing DNA DNA Fingerprints
• Compare the DNA sample to other DNA fingerprints
  until you find a match, or pattern that you are
  looking for
• Accuracy??
• The odds that 2 people will share the same DNA
  fingerprint 1 100 billion
• of people on Earth approx 7 billion

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Gel Electrophoresis
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Recombinant DNA

• Genetic engineering the process of altering the
  genetic material of cells or organisms to allow
  them to make new substances
• DNA recombination/Recombinant DNA
• Joining together DNA from two different organisms

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DNA Recombination

• Step 1 isolate the DNA and the plasmid of
  interest
• Plasmids small rings of DNA found naturally in
  some bacterial cells in addition to the main
  bacterial chromosome
• Step 2 restriction enzymes cut the DNA into
  fragments
• Step 3 fragments and plasmid DNA are joined
  together permanently by DNA ligase

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DNA Recombination Contd

• Step 4 recombinant DNA plasmids, each with
  different fragments of DNA, are inserted into
  bacterial cells
• These recombinant DNA plasmids are then copied
  each time the bacterial cell copies its own DNA
• Step 5 once a colony of bacterial cells
  containing the recombinant DNA plasmids is
  created, the recombinant DNA is removed to be used

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Recombinant DNA
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Central Dogma of Molecular Genetics

• How we go from DNA to RNA
• 1. replication (DNA copies itself)
• 2. transcription (DNA acts as a template for the
  production of messenger RNA (mRNA))
• 3. translation (mRNA carries coded information
  to ribosomes ribosomes "read" this information
  and use it to make proteins)

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The Central Dogma Contd
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Dogma Contd
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Replication Vocab you should know

• DNA replication process by which DNA is copied
  in a cell before a cell divides by mitosis,
  meiosis or binary fission
• Helicase enzymes that separate DNA strands by
  breaking the hydrogen bonds that hold the
  nitrogenous bases together

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Replication More vocab

• Replication Fork a Y shaped point that results
  when the two strands of DNA double helix separate
  so that the DNA molecule can be replicated
• DNA Polymerase an enzyme that catalyzes the
  formation of the DNA molecule

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Replication More Vocab

• Semi-conservative Replicaiton in each new DNA
  double helix, one strand is from the original
  molecule one strand is new
• Mutation a change in the nucleotide-base
  sequence of a gene or DNA molecule

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Facts about Replication

• Occurs during interphase of both the cell cycle
  for mitosis and for meiosis
• Happens to all of the DNA in the cell, not just
  selected parts (every chromosome)

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Replication (of DNA)

• Strands of DNA separate
• Helicase enzymes move along the strand of DNA
• They break the hydrogen bonds between the
  nitrogen bases
• The two strands separate, exposing a a Y-shaped
  region called the replication fork

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Replication Helicase the Replication Fork
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Replication Contd

• DNA polymerase enzymes add complementary
  nucleotides to the two separated strands
• The nucleotides are found free-floating around
  inside the nucleus
• As the nucleotides are added, covalent bonds form
  b/t the deoxyribose of one and the phosphate of
  the next

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Replication Adding Nucleotides Contd

• Adding nucleotides contd
• Hydrogen bonds are formed b/t the nitrogenous
  bases from the original strand and the
  nitrogenous bases on the newly added nucleotides

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Replication Adding Nucleotides Contd

• Adding Nucleotides contd
• DNA synthesis (creation) occurs in different
  directions on each strand
• As the replication fork moves along the original
  DNA, synthesis of one strand, the leading strand,
  follows the movement of the replication fork
• Synthesis of the other strand, the lagging
  strand, moves in the opposite direction, away
  from the replication fork

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Replication Adding Nucleotide Contd

• Adding Nucleotides Contd
• Because the nucleotides are added to the leading
  and lagging strands in opposite directions, it
  leaves gaps in the newly synthesized DNA, called
  Okazaki Gaps
• These gaps are later joined together by the
  enzyme DNA ligase

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Replication Leading Lagging Strands
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Replication Okazaki Fragments
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Replication Contd

• DNA polymerase enzymes finish replicating the DNA
  fall off
• The result of replication of a strand of DNA is
  two completely identical strands of DNA, each
  containing one old strand one new stand
  semiconservative replication

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Semi-Conservative Replication
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Replication contd

• DNA replication flash interactive

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DNA Replication Quiz

1. What are the three parts of the Central Dogma of
   molecular genetics?
2. What is the first thing that must happen in order
   for DNA to replicate itself?
3. What is the name of the enzyme that separates the
   two strands of DNA?

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Replication Quiz Contd

1. Helicase breaks the ________ bonds that hold the
   nitrogenous bases together.
2. The Y-shaped region that appears as the two
   strands separate is called the ________ _______.
3. After the strands separate, what is the second
   thing that happens as DNA replicates itself?

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Replication Quiz Contd

1. What is the name of the enzyme that adds the
   free-floating nucleotides to the two exposed
   strands of DNA?
2. The gaps created as the new DNA strands are being
   synthesized are called _________ __________.

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Replication Quiz Contd

1. What happens to the DNA polymerase after is
   finished being replicated?
2. Replication results in _____ () strands of DNA,
   each having one ____ strand and one _______
   strand.

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RNA Vocabulary You Should Know

• Ribonucleic Acid (RNA) a natural polymer that
  is present in all living cells that plays a
  role in protein synthesis
• Transcription the process of forming a nucleic
  acid by using another molecule as a template
  particularly the process of synthesizing RNA by
  using one strand of a DNA molecule as a template
• Translation the portion of protein synthesis
  that takes place at ribosomes that uses the
  codons in mRNA molecules to specify the sequence
  of amino acids in ploypeptide chains

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RNA move vocab

• Protein Synthesis the formation of proteins by
  using infomration contained in DNA carried by
  mRNA
• Ribose a five-carbon sugar present in RNA
• Messenger RNA (mRNA) a single-stranded RNA
  molecule that encodes the information to make a
  protein

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RNA more vocab

• Ribosomal RNA (rRNA) an organelle that contains
  most of the RNA in the cell that is responsible
  for ribosome function
• Transfer RNA (tRNA) an RNA molecule that
  transfers amino acids to the growing end of a
  polypeptide chain during translation
• RNA Polymerase an enzyme that starts
  (catalyzes) the formation of RNA by using a
  strand of DNA molecule as a template

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RNA More vocab

• Promoter a nucleotide sequence on a DNA
  molecule to which an RNA polymerase molecule
  binds, which initiates the transcription of a
  specific gene
• Termination Signal a specific sequence of
  nucleotides that marks the end of a gene
• Genetic Code the rule that describes how a
  sequence of nucleotides, read in groups of three
  consecutive nucleotides (triplets) that
  correspond to specific amino acids, specifies the
  amino acid sequence of a protein

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RNA More Vocab

• Codon in DNA, a three-nucleotide sequence that
  encodes an amino acid or signifies a start signal
  or a stop signal
• Anticodon a region of tRNA that consists of
  three bases complementary to the codon of mRNA
• Genome the complete genetic material contained
  in an individual

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RNA Ribonucleic Acid
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RNA Structure Comparison to DNA

• DNA
• Double stranded
• Sugar deoxyribose
• Bases
• Adenine
• Cytosine
• Guanine
• Thymine
• Usually much longer 100s or 1000s of genes

• RNA
• Single stranded
• Sugar ribose
• Nitrogenous bases
• Adenine
• Cytosine
• Guanine
• Uracil
• Usually much shorter

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RNA v. DNA
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RNA Types of

• mRNA messenger RNA
• Single stranded
• carries instruction from a gene to make a protein
• Eukaryotic cells carries messages from DNA in
  the nucleus to a ribosome in the cells cytoplasm

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mRNA
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RNA Types of

• tRNA transfer RNA
• transports amino acids to the ribosomes (rRNA) to
  be assembled into proteins
• Made of many nucleotides linked together

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tRNA
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RNA Types of

• rRNA ribosomal RNA
• This type of RNA makes up a part of ribosomes
• Ribosomes are organelles in each cell where
  protein synthesis occures
• clamp onto the mRNA use its info to assemble
  amino acids in the correct order to make proteins

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rRNA
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COMPOSITION OF RNA

• Made of nucleotides
• 1 phosphate group
• 1 ribose type of sugar
• 1 of 4 nitrogen bases

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RNAs NITROGEN BASES

• Purines
• Adenine (A)
• Guanine (G)
• Pyrimidines
• Cytosine (C)
• Uracil (U) instead of Thymine

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RNA Base-Pairing Rules

• Adenine pairs w/ Uracil (because there is no
  thymine)
• Cytosine pairs w/ Guanine

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RNA Base-Pairing
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RNA Quiz

1. Protein synthesis results in the creation of
   ________.
2. RNA has _______ strands.
3. RNA has the sugar _________.
4. Name the 4 bases for RNA.
5. RNA is usually ______ than DNA.
6. Name the 3 types of RNA.
7. What does mRNA do?

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RNA Quiz Contd

1. What does tRNA do?
2. rRNA is found on what cell part?
3. What are the base-pairing rules for RNA?

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Transcription

• The rewriting of genetic instructions from DNA
  into RNA
• transcribes DNA into genes
• Takes place in the nucleus of eukaryotic cells
• Takes place in the cytoplasm of prokaryotic cells

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Transcription Steps

• Unwinding separating the DNA strands
• The enzyme RNA polymerase binds to a promoter (a
  specific codon that starts transcription) on the
  DNA molecule
• DNA unwinds separates

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Transcription Steps Unwinding Separating DNA
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Transcription Steps

• Adding RNA nucleotides to create a strand of RNA
• RNA polymerase adds free-floating RNA nucleotides
  to one of the exposed DNA strands
• The nucleotides that are added are complementary
  to one of the DNA strands
• Only a specific section of the DNA strand is used
  to create the strand of RNA

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Adding RNA Nucleotides
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Transcription Steps

• Release of the RNA molecule
• RNA polymerase reaches a termination signal that
  tells it to stop
• RNA polymerase releases both the DNA the newly
  formed RNA molecule
• RNA created is mRNA
• The RNA molecule is free to perform its job
• RNA polymerase is available to transcribe more
  genes

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Releasing both DNA RNA
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Transcription Quiz

1. Transcription rewrites what?
2. Where does transcription take place in eukaryotic
   cells?
3. What is the 1st step in transcription?
4. What is the enzyme that unwinds separates DNA?

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Transcription Quiz Contd

1. What is the second step of transcription?
2. What are added to the exposed strand of DNA?
3. What tells RNA polymerase when to stop adding
   nucleotides?
4. The newly formed RNA is __RNA.

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Transcription Quiz Contd

1. When RNA polymerase reaches the terminal signal
   it releases both _______ _______.
2. What does RNA polymerase do after it releases the
   DNA newly formed RNA molecule?

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Protein Synthesis

• Gene segment of DNA , located on a chromosome
  that codes for a hereditary characteristic (like
  hair color)
• Genes direct the synthesis or making of proteins
  for that particular trait
• Genes use RNA to help make the appropriate
  proteins

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Protein Synthesis

• Genetic information flows in the following order
• Transcription
• Translation / Protein synthesis
• DNA ? RNA ? protein
• Proteins are important b/c they create do
  everything that our body is does

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The Genetic Code

• The code needed to convert the language of mRNA
  into proteins
• Proteins are made of amino acids
• Amino acids are made based on the nucleotide
  sequence in mRNA
• 3 adjacent nucleotides in mRNA specify a
  particular amino acid
• The 3 nucleotide sequence that encodes an amino
  acid, a start signal or a stop signal a codon

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Codons

• Codons can only code for one amino acid
• i.e. UUA Leucine and only leucine
• Each amino acid can be coded for by more than one
  codon
• the amino acid leucine can be coded for by all of
  the following codons
• i.e. UUA Leucine, UUG Leucine
• CUU Leucine, CUC Leucine
• CUA Leucine, CUG Leucine

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Codons Contd

• Start codons sequence of nucleotides in mRNA
  that signals where translation should begin
• Codes for the amino acid methionine
• Stop codons sequence of nucleotides in mRNA
  that signals where translation should stop
• Does not code for any amino acid

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Codons in mRNA
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Proteins

• Made of polypeptides
• Polypeptides are chains of amino acids linked by
  peptide bonds
• 20 different amino acids
• Polypeptide chains are 100s of 1000s of amino
  acids long
• The sequence of amino acids determine how the
  protein will fold twist into a 3d shape, the
  shape gives the protein its function

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Proteins
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Translation

• Is the synthesis or making of a protein
• The instructions for making a protein are
  transcripted from DNA into mRNA
• All three types of RNA are involved in
  translation

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Translation Steps

• Joining RNAs
• rRNAs tRNAs attach to a mRNA
• Enzymes attach an amino acid to one end of each
  tRNA
• The other end of the tRNA contains the anticodon
  for mRNA
• A tRNA carrying the amino acid methionine must be
  present to start the reading of mRNA attaches
  to a start codon on mRNA

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T-RNA
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Translation
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Translation Steps Contd

• Creation of a polypeptide chain
• tRNAs carrying correct amino acids, pair their
  anticodons w/ the codons on the mRNA strand
• Methionine detaches from the 1st tRNA after the
  2nd anticodon is added
• A peptide bond forms b/t methionine the 2nd
  amino acid to start a polypeptide chain
• The 1st tRNA exits the ribosome
• Ribosome moves one codon down on the mRNA strand

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Translation
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Translation Step Contd

• Polypeptide Chains Grow
• mRNA continues to move through the ribosome
• New tRNAs w/ correct anticodons move in peptide
  bonds are created b/t the amino acids of each
  tRNA
• The polypeptide chain moves from one tRNA to the
  next tRNA attaches to its amino acid

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Translation
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Translation Steps

• Stop Codon
• Polypeptide grows one amino acid at a time until
  it reaches a stop codon
• Polypeptide falls off

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Translation
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Translation Steps Contd

• End of Translation
• All the parts that are needed for translation
  come apart
• The last tRNA exits the ribosome
• The ribosome moves away from the mRNA
• All the parts are free to be used over over
  again

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Translation
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Translation Quiz

1. Proteins are made of ____ ____, which are made of
   3 RNA ______.
2. Polypeptides are chains of amino acids linked by
   _____ ____.
3. Translation is the synthesis of ________.
4. List the types of RNA involved in protein
   synthesis.

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Translation Quiz Contd

1. The first tRNA to be used during translation must
   carry the amino acid ________.
2. A polypeptide chain is started when methionine is
   bonded to the __________.
3. For the polypeptide chain to grow the mRNA must
   ____________.

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Translation Quiz Contd

1. The polypeptide chain stops growing when it
   reaches the ______ ________.
2. When the polypeptide chain reaches the stop codon
   what happens to the chain?
3. Once the polypeptide chain falls off, what
   happens to all the parts that assembled to
   translate RNA?