Protein Synthesis
DNA-->RNA-->Protein-->Trait
One Gene one Protein
• Beadle and Tatum
– Worked with the Mold Neurospora.
• Looked at metabolic pathway to synthesize the amino
acid Arginine
• Studies of inherited metabolic disorders first
suggested that phenotype is expressed
through proteins
• Studies of the bread mold Neurospora crassa
led to the one gene-one polypeptide
hypothesis
http://wps.prenhall.com/wps/media/objects/1552/1589869/web_tut/21_04/21_04_01a.swf (has a narrator)
http://www.dnalc.org/view/16360-Animation-16-One-gene-makes-one-protein-.html (no narrator)
Figure 10.6B
Mutate wild type fungus
*Supply all mutant isolates with
complete media
*Grow purified mutants
with minimal media
to find nutritional mutants
*Determine what is the nutritional limitation
 find mutation
There for the gene used to produce an enzyme
that helps cells manufacture Arginine amino acid
was mutated in that fungal strain
.
Beadle and Tatum This may not be totally accurate
Central Dogma
Overview: http://www.wiley.com/legacy/college/boyer/0470003790/animations/central_dogma/central_dogma.swf
RNA vs DNA
• Differences between the two nucleotides
– Sugar
• Ribose instead of deoxyribose
– Nitrogenous bases
• Uracil instead of Thymine
Types of RNA
• rRNA
– Ribosomes are made or rRNA and Proteins
• tRNA
– Folded into the “t” shape and carry an amino acid
on the end
• M-RNA
– Single Stranded
• HnRNA
– SNRPs
rRNA and Proteins
tRNA
Central Dogma
Overview: http://www.wiley.com/legacy/college/boyer/0470003790/animations/central_dogma/central_dogma.swf
Transcription vs Translation
• Transcription (DNA to RNA)
–
–
–
–
Copying mRNA from DNA
Promotor sequence
Some are modified before leaving nucleus (Eukaryotes)
Prokaryotes are not modified
• Translation (RNA to Amino Acid)
– Initiation
– Elongation
– Termination
Transcription
• Sense vs Antisense.
– Sense strant is the coding strand and would have the same
sequence as the mRNA with U’s replacing T’s.
– The Antisense strand is the strand that is transcribed.
↓Template strand
RNA polymerase
Reads DNA template 3’5’,
writes mRNA 5’ 3’
Transcription
transcription detail:
http://bcs.whfreeman.com/thelifewire/content/chp12/1202001.html
• Promotor
http://www.dnalc.org/resources/3d/13-transcription-advanced.html Detailed
realistic model
http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/tra
nscription.swf simple animation
– Site that the RNA polymerase recognizes and binds to
begin the process of Transcription
• RNA Polymerase
– Enzyme that reads 3’5’ and writes a 5’3’ mRNA
• Nucleoside Triphosphates
– The nucleotides that are put in by the polymerases
• Terminator
– Sequence that will code for a releasing factor
Transcription
transcription detail:
http://bcs.whfreeman.com/thelifewire/content/chp12/1202001.html
http://www.dnalc.org/resources/3d/13-transcription-advanced.html Detailed
realistic model
http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/tra
nscription.swf simple animation
Processing or not
http://www.four-h.purdue.edu/apple_genomics/flash/movie3.swf
http://bcs.whfreeman.com/thelifewire/content/chp14/1402001.html
Splicing (Eukaryotes)
http://highered.mcgraw-hill.com/sites/0072556781/student_view0/chapter14/animation_quiz_3.html
Cap and Tail
mRNA Processing: The Movie from the “Virtual Cell Animation collection:
molecular and Cellular biology
http://vcell.ndsu.edu/animations/mrnaprocessing/movie-flash.htm
Summary- eukaryotic control of gene expression
http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter16/control_of_gene_expression_in_eukaryotes.html
Intro overview
https://highered.mcgrawhill.com/sites/0072507470/st
udent_view0/chapter3/animat
ion__how_translation_works.
html
Summary of Translation
Step by step
http://www.stolaf.edu/peopl
e/giannini/flashanimat/molg
enetics/translation.swf
Ribosome Sites
Ribosome Sites
http://bcs.whfreeman.com/thelifewire/content/chp12/1202003.html
mRNA codes for AA
http://bcs.whfreeman.com/thelifewire/content/chp12/1202002.html
• Degenerate Code
Translation
• T-RNA molecules are matched to the proper
amino acid by an enzyme.
• Initiation, elongation, and translocation, and
termination
• Location and Process
http://www.dnalc.org/resources/3d/16-translation-advanced.html
Ribosome
Mutations and Protein Synthesis
• Can produce new alleles
– Must be in the gametes to be passed on
• Types of Mutations
– Point
• Can be harmless because of redundency (Degenerate) of code
– Chromosomal
•
•
•
•
Duplication
Inversion
Translocation
Deletion
Point Mutation and Frame Shift
Point Mutation and Sickle Cell
http://www.cleanvideosearch.com/media/action/yt/watch?videoId=1fN7rOwDyMQ
http://www.cleanvideosearch.com/media/action/yt/watch?videoId=9UpwV1tdxcs
Outcome of Sicke Cell
Translocation
Inversion
Deletion
Duplication
Ribosome with tRNA and Amino Acids