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Animations
• http://highered.mcgraw-hill.com/olc/dl/120077/micro06.swf
Home:
• http://highered.mcgraw-hill.com/sites/dl/free/0072437316/120060/ravenanimation.html
Figure 17.0 Ribosome
Gene
1 gene (DNA) → 1 polypeptide (protein)
1 gene = 100s-1000s nucleotide pairs
Gene
Nucleic Acid Language(G.C.T.A.)
≠ Protein Language
(20 Amino acids)
The triplet code
Transcription & translation within cells
Prokaryotic vs. Eukaryotic
20 amino acids
for proteins:nonpolar
polar
ionic
“Universal dictionary” of the genetic code
Few Exceptions:1. Mitochondrial DNA2. Chloroplast DNA3. Some single-celled organisms
Codons same across most life☺
Tobacco plant w/ firefly gene
Codons same across most life☺
Transgenic Coho Salmon(1 yr. old )
Source: Fisheries and Oceans Canada
http://www.oag-bvg.gc.ca/internet/English/att_c20041006pe04_e_13393.html
non-transgenic
Transgenic
GloFish® ???
Before
& After: http://www.youtube.com/watch?v=FpGdGTUuodw
[Zebra fish (Danio rerio)]
Stages of Transcription
1. Initiation
2. Elongation
3. TerminationRNA
polymerase
Initiation at a eukaryotic promoter
Elongation60 nucleotides/sec.
Termination
pre-mRNA
RNA processing; addition of the 5 cap and poly(A) tail
RNA processing: RNA splicing
The roles of snRNPs and spliceosomes in mRNA splicing
(& Ribozymes)
“Snurps”
* THREAANCADTCAJTKE
1 THREAANCADTCAJTKE
2 THREAANCADTCAJTKE
Alternative RNA splicing: (multiple genes may be stored in single DNA sequence)
* Spiced differently = two meanings 1,2
* THREAANCADTCAJTKE
1 THREAANCADTCAJTKE
2 THREAANCADTCAJTKE
Alternative RNA splicing: (multiple genes may be stored in single DNA sequence)
* Spiced differently = two meanings 1,2
* THREAANCADTCAJTKE
“THE- CAT – ATE” 1 THREAANCADTCAJTKE
“TEA - AND – CAKE”2 THREAANCADTCAJTKE
Alternative RNA splicing: (multiple genes may be stored in single DNA sequence)
* Spiced differently = two meanings 1,2
* THREAANCADTCAJTKE
“THE- CAT – ATE” 1 THREAANCADTCAJTKE
“TEA - AND – CAKE”2 THREAANCADTCAJTKE
Alternative RNA splicing: (multiple genes may be stored in single DNA sequence)
* Spiced differently = two meanings 1,2
* THREAANCADTCAJTKE
“THE- CAT – ATE” 1 THREAANCADTCAJTKE
“TEA - AND – CAKE”2 THREAANCADTCAJTKE
Alternative RNA splicing: (multiple genes may be stored in single DNA sequence)
* Spiced differently = two meanings 1,2
Spliceosomes
• http://highered.mcgraw-hill.com/olc/dl/120077/bio30.swf
Hypothesis:
Domain:specific function of an exon
*may explain sourcenovel proteins
The nucleus & its envelope
Translation: the basic concept
Codon/A.A. dictionary
The structure of transfer RNA (tRNA)
The structure of transfer RNA (tRNA)
80 nucleotides
Aminoacyl-tRNA synthetase: joins amino acid & tRNA
61 codons have only45 anticodons
How?
1 anti-codon recognizes
2+ codons
tRNA “Wobble”–Nitrogenous base I
• (pairs with U, C, A)
–Nitrogenous base U• (pairs with A, G)
* Wobble only occurs in third position of a codon.
Activated A.A.
The anatomy of a functioning ribosome
Ribosome and Protein Production
Steps:1) Initiation
2) Elongation
3) Termination
Each step requires Protein Factors
Initiation of translation
Elongation of translation
Termination of translation
Video of Ribosome & polypeptide synthesis
• http://highered.mcgraw-hill.com/olc/dl/120077/micro06.swf
Polyribosomes:Quick & Massive Protein Production
Video protein synthesis in Prokaryote & Eukaryotes
http://highered.mcgraw-hill.com/olc/dl/120077/bio25.swf
(Optional in class)
Review: the four levels of protein structure
A chaperonin in action
Post-translational structure changes:1.Chemical modification2.Removal of some A.A3.Cut/splice Polypeptide4.Multiple polypeptides mixed
“FREE” to “Bound” Ribosome:Signal mechanism (SRP) for targeting proteins to the ER, etc.
Bound Ribosomes:The nucleus, its envelope, & ER
also Chloroplasts, Mitochondria, other organelles
Ribosomes:Free & Bound
Endoplasmic reticulum (ER)
Golgi apparatus
Types of RNA in a Eukaryotic Cell
Diverse functions of RNA:1.Informational2.Structural3.Catalytic
Bacterial Protein Production: Coupled transcription and translation
Animation: http://highered.mcgraw-hill.com/olc/dl/120077/bio25.swf
Mutations
http://media.photobucket.com/image/collage/KatyChoirGrl05/Collages/EyeCollage.png?o=398http://eyemakeart.files.wordpress.com/2009/07/eye_colour_chart_by_delpigeon.jpg
Mutations: A change in genetic sequence (in DNA).
Types: 1. Base-pair substitution 2. Base Pair insertion/deletion
Mutations: A change in genetic sequence (in DNA).
Mutations: A change in genetic sequence (in DNA).
Point Mutation: one nucleotide pair changed
e.g. sickle-cell disease: point mutation(e.g. Base-pair substitution)
Base-pairsubstitution
HEC / ARA / NDM / AN. / …
Base-pair insertion or
deletion
“FRAMESHIFT”
THE / CAR / AND / MAN / …THE / CAP / RAN / DMA / N…
THE / CAR / AND / MAN / …
Causes of Errors (Mutations)
1. DNA Replication
2. Repair
3. Recombination
4. Mutagens:- X-rays, UV, Chemicals, ….
Where must mutations occur for a gene to be passed to future generations?
Gametes!
A summary of transcription and translation in a eukaryotic cell
End: Protein Synthesis
End of Material for Test 2Go to Next Chapter
Nuclei and F-actin in BPAEC cells
Veterans Day / Armistice Day World War I ends:Nov. 11, 1918 at 11 am
Charlotte Winters (Nov 10,1897- Mar 27, 2007)
Boonsboro, Maryland
Last female WWI vet dies at 109
Typical female yeoman uniform, however, this is not Mrs. Winters.
Last Navy vet of WWI dies at 105
Lloyd Brown (October 7 1901- March 29, 2007)
Charlotte Hall, MD