DNA and RNA

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