RNA and Protein Synthesis DNA structure...1 RNA and Protein Synthesis • DNA • Transcription •...
Transcript of RNA and Protein Synthesis DNA structure...1 RNA and Protein Synthesis • DNA • Transcription •...
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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