Gel electrophoresis

DNA sequencing

Cytoplasm

Nucleus

DNA

DNA is the genetic material within the nucleus.

Central Dogma

RNA

Protein

Replication

The process of replication creates new copies of DNA.

TranscriptionThe process of transcription

creates an RNA using

DNA information.

TranslationThe process of translation

creates a protein using

RNA information.

DNA Double Helix-Held Together with

H-Bonds

Base Pairs Double Helix

base: thymine(pyrimidine)

sugar: 2’-deoxyribose

monophosphate

no 2’-hydroxyl

(5’ to 3’)

5’

3’

base:adenine(purine)

1’2’

4’

3’ linkage

5’ linkage

Three Components of DNA Structure

Pyrimidines used in Base Pairs, DNA

6-membered rings only

Purines used in Base Pairs, DNA

Fused 5 and 6 member rings

DNA Base Pairing

A-T pairing

2 H-Bonds

G-C pairing

3 H-bonds

A-T and G-C Base Pairs Hold the DNA helices together

A-T and G-C Base Pairs Hold the DNA helices together

A-T and G-C Base Pairs Hold the DNA helices together

A-T and G-C Base Pairs Hold the DNA helices together

A-T and G-C Base Pairs Hold the DNA helices together

Transcription• The new RNA molecule is formed by incorporating • nucleotides that are complementary to the

template strand.

DNA coding strand

DNA template strand

DNA

5’

3’

5’

3’

G T C A T T C G G

C A G T A A G C C

G

RNA

5’

GG U C A U U C

3’

# of strands

kind of sugar

bases used

RNA Polymerase is the Enzyme that Catalyzes Transcription of DNA Information to RNA

DNA (Blue)

Newly Synthesized RNA (Red)

Active Site Metal (Pink)

Bridge Helix Moves DNA through Polymerase during RNA Synthesis (Green)

Transcription• The new RNA molecule is formed by incorporating • nucleotides that are complementary to the

template strand.

DNA coding strand

DNA template strand

DNA

5’

3’

5’

3’

G T C A T T C G G

C A G T A A G C C

G

RNA

5’

GG U C A U U C

3’

Translation• The process of reading the RNA sequence of an

mRNA and creating the amino acid sequence of a protein is called translation.

Transcription

Codon Codon Codon

Translation

DNA

T T C A G T C A G

DNAtemplatestrand

mRNA

A A G U C A G U C MessengerRNA

Protein Lysine Serine ValinePolypeptide(amino acidsequence)

• The “words” of the DNA “language” are triplets of bases called codons

– 3 bases or nucleotides make one codon

– Each codon specifies an amino acid

– The codons in a gene specify the amino acid sequence of a polypeptide

Genetic information written in codons is translated into amino acid sequences

• Virtually all organisms share the same genetic code

• All organisms use the same 20 aa

• Each codon specifies a particular aa

The genetic code is the Rosetta stone of life

Figure 10.8A

• Tryptophan and Methionine have only 1 codon each

• All the rest have more than one

• AUG has a dual function

• 3 stop codons that code for termination of protein synthesis

• Redundancy in the code but no ambiguity

Figure 10.8A

http://www.dnalc.org/ddnalc/resources/sangerseq.html

http://www.shsu.edu/~chm_tgc/sounds/flashfiles/GE.swf

Shotgun sequencing: assembly of random sequence fragments