dna and rna
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DNA AND RNACh. 12
DNA: the genetic material
Griffith - 1928, used a bacteria that causes pneumonia to figure out that there are smooth (S) strains and rough (R) strains, the S cells killed mice, while the R cells did not, a mixture of R and S Cells did however kill the mouse, he conclude that there was a transformation from R to S
Avery - 1944, identified molecule that transferred R into S
Hershey and Chase - 1952, discovered that DNA is the transforming factor by using Radioactive Labeling
Griffith’s Experiment
Hershey and Chase Experiment
DNA Structure
Nucleotides - subunits of nucleic acids, contain a 5-carbon sugar, a phosphate, and a nitrogenous base.
DNA adenine (A), guanine (G), cytosine (C), and thymine
(T) RNA
adenine, guanine, cytosine, and uracil (U) A and G are double rings so they are called
Purine Bases C, T and U are single rings called Pyrimidine
Bases
Chargaff
Chargaff - found that the amount of G is equal to the amount of C, and A is equal to T Chargaff's Rule - G=C, and A=T
Structure and Bases
Structure and Bases
DNA History Con’t
X-ray diffraction - used to figure out the shape of DNA (double helix)
Watson and Crick - Double Helix structure 1. two outside strands consist of alternating
deoxyribose and phospate 2. cytosine and guanine bases pair to each
other by three hydrogen bonds 3. thymine and adenine bases pair to each
other by two hydrogen bonds A purine always bonds to a pyrimidine base,
so A=T and C=G Therefore, C+T = G+A
DNA Structure
Top rail goes from the 5' carbon on the left to the 3' carbon on the right ( 5'-3')
Bottom rail goes from the 3' carbon on the left to the 5' carbon on the right (3'-5')
Chromosome Structure Human chromosomes have anywhere
from 51 million to 245 million base pairs
DNA Replication
Semiconservative Replication - parental strands of DNA separate, serve as templates and produce DNA molecules that have one strand of parental DNA and one strand of new DNA
DNA Helicase - enzyme responsible for unwinding the DNA, breaks the Hydrogen bonds between the bases
When unzipped RNA primase adds a primer or starting point on each DNA strand
DNA Polymerase - enzyme that adds the nucleotides to the new DNA strand starting at the 3' end and then zips the strands back up
DNA Replication
DNA Replication Con’t
Chargaff's rule is demonstrated therefore there are exact copies of each other
Leading strand - strand that is copied as the DNA unwinds, built continuously
Lagging strand - replicates in the opposite direction as the DNA unwinds
Okazaki fragments - chunks 100-200 nucleotides long on the lagging strand where replication takes place
DNA Replication
Nerdy Scientist Pick-Up Line
RNA
RNA - contains ribose (sugar), uracil (replaces thymine), and is usually single stranded mRNA - messenger RNA, formed from one
strand of a DNA molecule, they direct the synthesis of specific proteins
rRNA - ribosomal RNA, forms ribosomes in the cytoplasm
tRNA - transport RNA, smaller segments of RNA that transport amino acids to the ribosome
RNA
introns - sequences that are not coded for on the DNA molecule
exons - the sequences that are used in the code
DNA ultimately makes proteins, there are also 20 different amino acids that make up proteins
DNA sequences (codes) make up these amino acids
Codon - three base codes in DNA and mRNA that make up amino acids
Transcription
Transcription - DNA code is transferred to mRNA in the nucleus, then uses the code to synthesize proteins
Template strand - the strand of DNA that is copied by the RNA
Nontemplate strand - the strand of DNA that is not used by the RNA
Translation
Translation - once the mRNA is synthesized and processed, it moves to the ribosome, it attaches to the ribosome and the code is read and translated into proteins
tRNA - is basically an interpreter for the mRNA codon sequence
anticodon - three base coding sequence that is complimentary to the codon sequence
Amino Acids
What is the Sequence?
Start - Serine - Histidine - Tryptophan - Glycine - Stop
Start - Proline - Asparagine - Isoluecine - Valine - Glutamate - Stop
mRNA~ AUG - CCG - UUU - GGA - UGG - UGU - GGG -
UAA
What is the Sequence Con’t Amino Acids
tRNA
DNA
Terms
Gene regulation - ability of an organism to control which genes are transcribed in response to the environment
Operon - section of DNA that acts as an on/off switch for transcription
Mutation - permanent change occur in a cells DNA point mutation - one base is exchanged for another
(substitution) Frame shift mutation - when a gain or a loss of a base Duplication - when bases are duplicated Expanding mutation - repetitive bases
Mutagen - Certain chemicals and radiation that can damage DNA sequences
Genetic Mutations
Test Info
TEST - 10 questions Vocabulary with its definition
DNA Helicase, tRNA, DNA polymerase, Codon, rRNA, mRNA, genetic code, ribose, deoxyribose, RNA polymerase, anticodon, replication, transcription, translation, ribosomes, x-ray diffraction, and Hydrogen bond
Historical Contributions Match the scientist with his/her contributions
Griffith, Avery, Hershey Chase, Franklin, Watson Crick, Chargaff Comparing Molecules
Compare molecules of DNA, mRNA, and tRNA know the structure!!!!!!!
Matching Codons Fill in a table like we did in class
know the DNA, mRNA, tRNA, and the amino acid Processes
Exactly from our notes The process of DNA replication, transcription, and translation
Book Review
Review Page 353 #’s: 3-5, 8-11, Pg.354 #’s: 17, 18, 26-28, 30, 34
Pg.356-357 #’s: 1-5, 9, 10, 12, 13, 16-18
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