Download RNA & Protein Synthesis

Sections 3-4
Structure of RNA
 Made of nuleotides
 Three differences between
DNA & RNA
 Sugar


DNA = deoxyribose sugar
RNA = ribose sugar
 RNA is single stranded
 RNA uses Uracil instead
of Thymine to bond with
Adenine
Types of RNA
 Three types of RNA
 mRNA

Messenger RNA
 rRNA

Ribosomal RNA
 tRNA

Transfer RNA
Types of RNA
 Messenger RNA
 This is a copy of complimentary strand of DNA
 Eventually will code for a protein to be made
Types of RNA
 Ribosomal RNA
 RNA found in ribosomes (organelles in the cell)
Types of RNA
 Transfer RNA
 Help produce a protein from mRNA
 Brings amino acids (monomer of protein) to ribosome to
bond them together and make a whole protein
Transcription
 Taking DNA and making an RNA copy
 Occurs in the cell’s nucleus
 RNA polymerase opens the DNA and adds RNA copy
to the template
 Once this is made it is called pre-mRNA
RNA Editing
 Pre-mRNA is a rough draft to the final copy of mRNA
 Some parts of pre-mRNA are not needed to make a certain
protein
 These unnecessary parts are called introns
 Introns get cut out of pre-mRNA
 Before leaving the nucleus, mRNA needs to get a cap and
tail to finalize the RNA strand
The Genetic Code
 Proteins are made of amino acids
 There are 20 amino acids
 In order to make a protein from a strand of mRNA, the
mRNA is read in a 3 letter sequence called codons
The Genetic Code
 Each three letter codon represents an amino acid
 DNA = AGCGTGCCA
 RNA =
 Codons =
 Amino acids =
The Genetic Code
 RNA knows when to start and stop based on the
codons read
 There is ONE start codon: AUG
 There are THREE stop codons: UAA, UAG, UGA
Translation
 Taking mRNA and making a protein
 Occurs in the cytoplasm on a ribosome
 tRNA brings specific amino acids to ribosome
 If mRNA = AUG, then tRNA = UAC
 The tRNA has the anti-codon
Translation
 As new tRNA brings amino acids to the ribosome, past
ones break off leaving just amino acids bonded to each
other
 This continues until one of the three STOP codons is met
 Finished amino acid strand goes through protein folding
Mutations
 Changes in the DNA sequence that affect the cell
 Two types of mutations
 Gene mutation
 Chromosomal mutation
Gene Mutation
 Point mutation
 A change in one nucleotide in a DNA
sequence
 Occur only in a single point of the DNA
 Can sometimes be a problem
 Frameshift mutation
 A change in the reading frame of DNA
 Since DNA is read in 3 letter codons, if
there is an insertion, deletion, or large
change in these codons the frame is
changed
Chromosomal Mutation
 A change in the number of chrom0somes in the cell
 Four types
 Duplication
 Deletion
 Inversion
 Translocation