Review for Ch. 12
-
Upload
bridgetteflaherty -
Category
Education
-
view
226 -
download
1
description
Transcript of Review for Ch. 12
Griffith..
• Griffith-1st major experiment led to discovery of DNA as genetic material(MOUSE AND BACTERIA) …
• 2 bacteria harmful and harmless.. Heated harmful mixed with harmless and they transform which is what he wanted to find.
His experiment….
Avery
• Identified molecule transformed R strain of bacteria to S strain
• S=deadly and smooth R= rough and harmless
• Concluded when cells were killed when DNA was released.
• R bacteria incorporated this DNA into their cells changed into S cells
Hershey and Chase
• Used radioactive labeling to trace DNA and protein.
• Concluded that the vital DNA was injected into the cell and provided the genetic information needed to produce new viruses.
Their experiment…
Watson and Crick
• Built a model of double helix that confronted others’ research.
• Outside 2 strands made of alternate deoxyribose and phosphate.
• Inside connectors cytosine and guanine base pairs by 3 hydrogen bonds.
• Inside connectors thymine and adenine base pairs to each other by 2 hydrogen bonds.
Their model…
Chargaff
• Analyzed the amount of adenine, guanine, thymine, and cytosine into the DNA of various species.
• Found that C=G and T=A.
DNA replication
• Semiconservative- parental strands of DNA separate, serves as templates, and produces DNA molecules that have one strand of parental DNA and one new strand.
• Simple steps to remember: Unwinds, Base Pairing, Replicates, Rejoins.
Video so you can understand
• http://www.wiley.com/college/pratt/0471393878/student/animations/dna_replication/index.html
Protein Synthesis
• Basic steps: transcription, separates junk and info, translation, goes to cytoplasm, transcription, finds ribosome, copies.
• In transformation
DNA T= A RNA
A=U
G=C
C=G
Video so you understand
• http://www.wisc-online.com/Objects/ViewObject.aspx?ID=AP1302
Gene Regulation
• Ability of an organism to control which genes are transcribed in response to the environment.
• In prokaryotes, operon controls the transcription of genes in response to changes in the environment.
• Sections are: Operator, Promoter, Regulatory gene, and genes coding for proteins.
Gene Regulation Cont.
• In eukaryotic regulation, it must control transcription.
• They use transcription factors (next slide) and the complex structure of eukaryotic DNA.
Transcriptions Factors
• They ensure a gene is used at the right time and that the proteins are made in the right amounts.
• https://www.youtube.com/watch?v=vJSmZ3DsntU
• But remember, before it leave nucleus introns are removed.
Operon
• Operon- section of DNA contains the genes for the proteins needed for a specific metabolic pathway.
• Example in class : Lac Operon which is people that are lactose intolerant.
• Link to Video with Lac Operon:
http://www.biostudio.com/d_%20Lac%20Operon.htm
Beadle and Tatum
• Their experiment showed that one gene codes for one enzyme.
• We now know that 1 gene codes for 1 polypeptide.
Hox Genes• Hox genes are responsible for the general
body pattern of most animals.
RNA Interference
• RNA interference can stop the mRNA from translating its message.
• Video link to help you understand: http://www.nature.com/focus/rnai/animations/animation/animation.htm
Mutations
• A permanent change that occurs in a cell’s DNA is called a mutation.
• Types of mutation: Point mutation, Insertion, and Deletion .
• Insertion and Deletion cause frame shift, add or take away one of the codes.
• Point mutation is like substituting one code for another.
Causes of Mutation
• Can occur spontaneously
• Chemical and radiation can also damage DNA.
• High-energy forms of radiation. Such as X Rays and gamma rays, are highly mutagenic.
Protein Folding and Stability
• Substitutions also can lead to genetic disorders.
• Can change both the folding and stability of the protein.
• Video for help (just look at overview): http://www.wiley.com/college/boyer/0470003790/animations/protein_folding/protein_folding.htm