animations hill.com/olc/dl/120077/micro06.swf hill.com/olc/dl/120077/micro06.swf home:

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