Forensic DNA Analysis: Protein Synthesis
Overview: The Flow of Genetic Information
 The information content of DNA is in the form of specific
_________________________________________________________
 The DNA inherited by an organism leads to specific traits by dictating the
______________________________________________________________
 Proteins are the links between ______________ and _____________________
 _____________________________, the process by which DNA directs protein
synthesis, includes two stages: transcription and translation
The central dogma…
 ____________ ___________ __________________
 RNA is the intermediate between genes and the proteins for which they code
 _________________________ is the synthesis of RNA under the direction of DNA
o Happens in the _____________________
o Transcription produces ______________________________ (mRNA), carries DNA message to ribosome
 _____________________ is the synthesis of a polypeptide, which occurs
under the direction of mRNA
o ______________________________ are the sites of translation
Codons
 There are ______________, but there are only four nucleotide bases in DNA
 The flow of information from gene to protein is based on a
___________________: a series of non-overlapping, three-nucleotide words
 _______________=_________________=_________________________
Overview
 During transcription, one of the two DNA strands called the ______________
_____________________ provides a template for ordering the sequence of
nucleotides in an RNA transcript
 During translation, the mRNA base triplets, called codons, are read in the
_________________________________________________
 Each codon specifies the order of amino acids to make a
protein
 RNA bases: A, G, C, and____________ instead of ___________
Practice
 What amino acid is AGU? ________________
 GAU? _________________
 AUG? _________________
 UAA? _________________
What are the codons for Gly (glycine)? _______________________
Transcription
The three stages of transcription:
Initiation
 ______________signal the initiation of RNA synthesis and
____________________________ mediate the binding of RNA polymerase and the initiation of transcription
Elongation
 __________________________ unwinds helix and adds RNA nucleotides to the 3’ end. DNA helix reforms after
RNA Polymerase moves away
Termination
 The _________________________________ after
the mRNA is formed
mRNA processing
 mRNA is ‘processed’ after transcription to prepare
it for leaving the nucleus to travel to the ribosome.
o
o
It receives a _____________ and _________________ to the 3’ end
Parts of the mRNA transcript are removed (___________)
Translation
The three stages of translation:
Initiation
 _______________________________________________ and
moves along it until it reaches a start codon (________)
Elongation
 _______________________ (transfer) brings
_____________________________________and adds them 1 by
1 based on the mRNA sequence
Termination
 Codons (3-bases) are read and amino acids are added until the
ribosome reaches a ______________________ (UGA, UAA, UAG)
http://www.youtube.com/watch?v=5bLEDd-PSTQ
Mutations
 ________________________________________ are changes in the genetic material of a cell or virus
 _____________________________________ are chemical changes in just one base pair of a gene
Types of Point Mutation
 A ______________________________ replaces one nucleotide with another pair
 __________________________ have no effect on the amino acid produced by a codon (codes for the same
amino acid)
 ___________________________________ still code for an amino acid, but not the right amino acid
 ____________________________________________ change an amino acid codon into a stop codon, nearly
always leading to a nonfunctional protein
 ____________________________ and __________________________ are additions or losses of nucleotide
pairs in a gene (changes the reading frame)