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Chapter 12: Molecular Genetics
Bell Ringer: Please name your favorite scientist or contributor to science, and list something that they accomplished
Chapter 12 Tentative Itinerary
Today - Start 12.1
Tomorrow - Finish 12.1
Thursday 2/20 - 12.1 quiz, start movie
Friday 2/21 - finish movie
Monday 2/24 - 12.2-12.3
Tuesday 2/25 - coding lab
Wednesday 2/26 - 12.2-12.3 quiz, protein lab
Thursday 2/27 - start 12.4
Friday 2/28 - finish 12.4, assign review
Monday 3/3 - correct chapter review, further review
Tuesday 3/4 - Chapter 12 test
•Griffith
•Avery (McCarty an McCluget)
•Hershey and Chase
•Chargaff
•Rosalind Franklin
•Watson and Crick
•Griffith
•Avery (McCarty an McCleod)
•Hershey and Chase
•Chargaff
•Rosalind Franklin
•Watson and Crick
•Griffith
•Avery (McCarty an McCleod)
•Hershey and Chase
•Chargaff
•Rosalind Franklin
•Watson and Crick
What makes up DNA?
Nucleotides: subunits of nucleic acid, consists of carbon (sugar), phosphate and a nitrogenous base.
P
C
N
Erwin Chargaff
* There are four different nitrogenous bases in nucleotides* Cytosine, Guanine, Adenine and Thymine* Chargaff analyzed the amount of each in various species of living organisms* Found that the amount of Cytosine is nearly equal to the amount of Guanine*The amount of Thymine is nearly equal to the amount of Adenine
*Chargaff’s rule: C=G and T=A
•Griffith
•Avery (McCarty an McCleod)
•Hershey and Chase
•Chargaff
•Rosalind Franklin
•Watson and Crick
Double Helix- a twisted a ladder shape
•Griffith
•Avery (McCarty an McCleod)
•Hershey and Chase
•Chargaff
•Rosalind Franklin
•Watson and Crick
Photo 51 + Chargaff’s Rule + some math = Discovering the Structure of DNA
purine- double ringed nitrogenous bases; adenine and guanine
pyrimidine- single ringed nitrogenous bases; cytosine and thymine/uracil
Histone- Group of proteins
Nucleosome- DNA wrapped around a histone
•Griffith
•Avery (McCarty and McCleod)
•Hershey and Chase
•Chargaff
•Rosalind Franklin
•Watson and Crick
semi-conservative replication- proven by John Cairns through autoradiography, parental strands of DNA separate, serve as templates, and produce DNA molecules with one strand of parental DNA and one strand of new DNA
3 Main Stages:I. Unwinding- DNA helicase, enzyme that unwinds and unzips the DNAII. Base Pairing- DNA polymerase, adds nucleotides to the 3’ end- Okazaki fragments = 100-200 nucleotide long strands of DNA which are connected by DNA ligaseIII. Joining- DNA polymerase removes RNA primers and links the two strands
Central Dogma
DNA RNA Proteins
What is RNA?
*DNA = deoxyribose nucleic acid, 2 strands
*RNA = ribose nucleic acid, 1 strand
*Nucleotide base Thymine in DNA is replaced with Uracil in RNA
*Three types of RNA:-Messenger RNA (mRNA)-Ribosomal RNA (rRNA)-Transfer RNA (tRNA)
Transcription
*The process of synthesizing or creating mRNA from DNA
*RNA polymerase is an enzyme that binds to DNA, reads the sequence, and produces an RNA copy of the segment -RNA polymerase I creates rRNA-RNA polymerase II creates mRNA-RNA polymerase III creates tRNA
*mRNA is shorter than the strand of DNA it copies-introns = intervening sequences skipped over-exons = sequences from the DNA that remain in the mRNA
What is this Code?
Codon- three base code in DNA or mRNAAnticodon- three base code that complements a codon, is read 3’ to 5’
Page 338
Translation
* The creation of a protein from a ribosome translating the mRNA sequence
*mRNA travels to a ribosome; to do this, it must leave the nucleus and find a ribosome in the cytoplasm
*Ribosome translates the sequence in the mRNA to synthesize a protein
Gene Regulation- ability of an organism to control which genes are transcribed in response to changes in the environmentoperon- a section of DNA that contains genes for the proteins needed for a specific metabolic pathway
*operons require an operator, a promoter, a regulatory gene, and the genes coding for proteins
trp operon- responsible for transcribing the enzymes necessary for tryptophan synthesis; is repressed when there is tryptophan in the environment, is activated in an absence of tryptophan
lac operon- responsible for transcribing the enzymes necessary for lactose digestion; is repressed until an inducer is present to pull the repressor off the promoter
Hox Genes
Mutations
*Occur as mistakes in DNA replication, one base change can have enormous repercussions in the cell/organism
* 3 kinds you need to know:-substitutions-frameshifts (insertion/deletions)-duplications
SubstitutionsMissense Mutation- a substitution which leads to the change in charge of the amino acidNonsense Mutation- a substitution that creates a stop codon in the middle of the sequence
FrameshiftsDeletions- deletes a base, shifts the codons downwardInsertions- inserts a base, shifts the codons upward
DuplicationsDuplication- repeating of a codonTandem Repeats- repeating of a codon further with every generation
THE BIG FAT CAT ATE THE WET RAT
*Normal*
THE BIZ FAT CAT ATE THE WET RAT
THE BIG RAT
THB IGF ATC ATA TET HEW ETR AT
THE BIG ZFA TCA TAT ETH EWE TRA
THE BIG FAT FAT CAT ATE THE WET RAT
THE BIG FAT FAT CAT ATE THE WET RATTHE BIG FAT FAT FAT CAT ATE THE WET RATTHE BIG FAT FAT FAT FAT CAT ATE THE WET RAT
THE BIG FAT CAT ATE THE WET RAT
*Normal*
THE BIZ FAT CAT ATE THE WET RAT
THE BIG RAT
THB IGF ATC ATA TET HEW ETR AT
THE BIG ZFA TCA TAT ETH EWE TRA
THE BIG FAT FAT CAT ATE THE WET RAT
THE BIG FAT FAT CAT ATE THE WET RATTHE BIG FAT FAT FAT CAT ATE THE WET RATTHE BIG FAT FAT FAT FAT CAT ATE THE WET RAT
Deletion
Missense
Nonsense
Insertion
Duplication
Tandem Repeats
Mutagens
Things that cause mutations
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