Nucleic Acids and Protein Synthesis 
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Proteins

DNA

 

History of DNA discovery

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 DNA Replication

    

OKAZAKI FRAGMENTS

RNA

 mRNA

tRNA

rRNA

 Amino Acids

Genetic Code (RNA)

 Amino Acid

 3 Letter
Abbreviation

 Codons

 Alanine

 Ala

 GCA GCC GCG GCU

 Arginine

 Arg

 AGA AGG CGA CGC CGG CGU

 Aspartic Acid

 Asp

 GAC GAU

 Asparagine

 Asn

 AAC AAU

 Cysteine

 Cys

 UGC UGU

 Glutamic Acid

 Glu

 GAA GAG

 Glutamine

 Gln

 CAA CAG

 Glycine

 Gly

 GGA GGC GGG GGU

 Histidine

 His

 CAC CAU

 Isoleucine

 Ile

 AUA AUC AUU

 Leucine

 Leu

 UUA UUG CUA CUC CUG CUU

 Lysine

 Lys

 AAA AAG

 Methionine

 Met

 AUG

 Phenylalanine

 Phe

 UUC UUU

 Proline

 Pro

 CCA CCC CCG CCU

 Serine

 Ser

 AGC AGU UCA UCC UCG UCU

 Threonine

 Thr

 ACA ACC ACG ACU

 Tryptophan

 Trp

 UGG

 Tyrosine

 Tyr

 UAC UAU

 Valine

 Val

 GUA GUC GUG GUU

 Start

 

 AUG

 Stop

 

 UAA UAG UGA

 

  Practice Table:

DNA
Codon

mRNA
Codon

tRNA
Anticodon

Amino
Acid

 

GCU

 

 

TAC

 

 

 

 

 

AUU

 

 

UUU

 

 

TCA

 

 

 

 

 

UCU

 

CTT

 

 

 

 

 

ACU

 

 

ACU

 

 

 Protein Synthesis

 Steps in Transcription

  1. DNA helicase (enzyme) uncoils the DNA molecule
  2. RNA polymerase  (enzyme) binds to a region of DNA called the promoter which has the start codon TAC to code for the amino acid methionine
  3. Promoters mark the beginning of a DNA chain in prokaryotes, but mark the beginning of 1 to several related genes in eukaryotes
  4. The 2 DNA strands separate, but only one will serve as the template & be copied
  5. Free nucleotides are joined to the template by RNA polymerase in the 5 to 3 direction to form the mRNA strand
  6. mRNA sequence is built until the enzyme reaches an area on DNA called the termination signal
  7. RNA polymerase breaks loose from DNA and the newly made mRNA
  8. Eukaryotic mRNA is modified (unneeded sections snipped out by enzymes & rejoined) before leaving the nucleus through nuclear pores, but prokaryotic RNA isnt
  9. All 3 types of RNA called transcripts are produced by this method

 Steps in Translation

  1. mRNA brings the copied DNA code from the nucleus to the cytoplasm
  2. mRNA attaches to one end of a ribosome; called initiation
  3. tRNAs attach the correct amino acid floating in the cytoplasm to themselves
  4. tRNA with its attached amino acid have 2 binding sites where they join the ribosome
  5. The tRNA anticodon reads & temporarily attaches to the mRNA codon in the ribosome
  6. Two amino acids at a time are linked together by peptide bonds to make polypeptide -chains (protein subunits); called elongation
  7. Ribosomes) move along the mRNA strand until they reach a stop codon (UAA, UGA, or UAG); called termination

  1. tRNAs break loose from amino acid, leave the ribosome, & return to cytoplasm to pick up another amino acid

Click here for an animation of Translation 

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