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RNA and Protein Synthesis• DNA• Transcription• Translation• Control/regulation of protein production• 3 roles of DNA

1. Control2. Inheritance3. Evolution– The genetic code is a triplet code.– The genetic code is a redundant code.– The genetic code is an unambiguous code.– The genetic code is a universal code.

DNA structure

DNA replication

The Xeroxing of the DNA

Faithful copies are the aim

Replication BubblesA strand of DNA can be copied from many places at the same time.

Speeds up the copying

3’ and 5’ ends

• DNA backbones runs in opposite directions

• 3’ (3-prime) and 5’ (5-prime) ends

• 3’ carbon has on OH, 5’ carbon has the phosphate group

• When DNA is replicated it grows by adding nucleotides to the 3’ end only, so it grow in the 5’ 3’ direction only.

3’ 5’; 5’ 3’

• Always make the copy from the ‘other’ strand

• DNA polymerase adds nucleotides, and DNA ligase links small pieces together

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Genotype to Phenotype!

Transcribe: copy

Translate: interpret DNA into Protein

Transcription

• Three phases of transcription– Initiation– Elongation– Termination

mRNA

Transcription and TranslationDNA: A, C, G, T

A=T

C=G

RNA: A, C, G, U

A=U

C=G

DNA= thymine RNA= uracil

Each three nucleotides makes a codon…why??

Codons and Amino Acids• 4 (A,G,T,C)

nucleotides translate in 20 different amino acids…how?

• Letters of the Alphabet

• Codons are the key

• Lets do the hand out!

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Exons and Introns The Ribosome

Ribosomes, mRNA, and tRNA

Translation of RNA to Protein: Initiation

tRNA

Back to the handout

Translation: Elongation

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Summary of Transcription and Translation- DNA RNA Protein

Summary of Transcription and Translation

Transcription Errors

Change one nucleotide, and you get sickle-cell disease

Transcription Errors- mutations

Substitutions occasionally be good

Insertion/deletion is almost always disastrous, cause a ‘frame shift’

In general-error = bad

thebigcatatethefatrat

Gene Regulation “Pipeline” Gene Regulation in prokaryotes: the lac operon

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Gene Regulation in prokaryotes: the lac operon Regulation in Eukaryotes

Extracellular effectors on transcriptional control: Protein Activation

Developmental RegulationA fly, is a worm,

is a mouse, is a human, is a…

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A leg, is a leg, is a leg…

“Homeotic genes” -segmentation/large pattern genes

and Homeobox/Hox Genes- genes that control other genes-“Master Controllers”

Messin’ with the Hox!

Cancer: oncogenes Fig. 10.20

Table 10.1 Genetic Engineering

• Recombinant DNA Technology– Combining genes from different source

• Different ways to transfer DNA

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DNA Transfer in Bacteria Fig. 11.4

Plasmid Replication Using Plasmids in GE

Restriction Enzymes

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Using mRNA Using mRNA, cont.

Tagging DNA to find a gene DNA probes to find clones

Gel Electrophoresis PCR: Polymerase Chain Reaction

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DNA study in CDC laboratory

Restriction Fragments DNA fingerprints from a murder case

Genes and ‘Junk”

• A lot of our DNA is “junk” (97%???)

•Repetitive DNA: non-coded regions between genes

Genetic Engineering: “Pharming”Transgenic or

Genetically modified food

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Pesticide: Bt• "Bt" is short for Bacillus thuringiensis, a

soil bacterium • The bacteria produces toxins that kill

insects• The Bt genes are used to confer protection

to different crops

“Yo quiero Bt Corn”

Rice is nice• GMO rice = ‘Golden Rice’• 500,000 children to go blind

every year • White rice provides few

nutrients, protein but is a staple for ~ ½ the world’s population

• Leaves = Beta Carotene but not in seeds (rice)– So can’t breed rice seeds to

produce BC• GMR the only answer…or is

it?

“Pharm” animals

•Transgenic plants, animals and bacteria can produce helpful chemicals for human use

•Sheep produce human blood proteins in their milk

GM Foods- Ecosystem• Health to Ecosystem-

Negative– Super weeds– Cross “pollination”

worries– Allergens– Use more of our

pesticide or herbicide– Unintended targets

• Monarchs and Bt– Lower nutrition– Unknown risks!

• Health to Ecosystem-Positive– Use less water– Use less fertilizers– Use less

pesticides/herbicide?– Faster growth– Less spoilage– Better flavor– Can grow in slightly

salty soils

Gene therapy procedure “Dolly”

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Stem cells