Miescher
Discovered nucleic acid in white blood cells of pus (nuclein)
Griffith
Discovered that genes from one cell can be taken in by another cell
Avery & others
Discovered that DNA stores and transmits genetic information (DNA is necessary for transformation)
Hershey and Chase
Concluded that DNA makes up genes using bacteriophages
Chargaff's rules
% of C=G and T=A
Rosalind Franklin (and Wilkins)
Used x-ray diffraction to learn about the coiled structure of DNA
Watson and Crick
Built a 3D model of DNA as a double helix structure
A stands for...
Adenine
C stands for...
Cytosine
G stands for...
Guanine
T stands for...
Thymine
Purines
Adenine and Guanine; Double ring bases
Pyrimidines
Cytosine and Thymine; Single ring bases
antiparallel
Two sides of DNA are_____ based on the location of the carbons on the sugar molecule
OH
3' end has
5' end has
Phosphate
Bases to sugar
Covalent Bond
Sugars to phosphate
Covalent Bond
Nitrogen bases to each other
Hydrogen bond
Helicase
Unzips and unwinds DNA by breaking hydrogen bonds between bases
Topoisomerase
Prevents DNA tangling
Replication Fork
Y shaped region where strands of DNA are replicating
RNA Primase
Marks starting point with primer
Primer
Tells DNA polymerase where to start
DNA Polymerase function 1
Builds DNA by adding 1 nucleotide at a time
DNA Polymerase function 2
Reads 3'->5'
DNA Polymerase function 3
Builds 5'->3'
DNA Polymerase function 4
Proofreads DNA
DNA Polymerase function 5
Removes primer
Ligase
Connects Okazaki fragments together
Okazaki fragment
Small segments of DNA built during construction of the lagging strand
Leading strand
3' side facing the replication fork
Lagging strand
5' side facing the replication fork
Transcription
DNA->RNA; Occurs in the Nucleus
Translation
RNA->Polypeptides; Occurs in the cytoplasm at ribosomes
RNA
Single strand of nucleotides
In RNA, Thymine is replaced by...
Uracil
3 forms of RNA
Messenger RNA 2. Ribosomal RNA 3. Transfer RNA
Messenger RNA
Blueprint for protein synthesis; Travels from nucleus to ribosome
mRNA start codon
AUG
Transfer RNA
Translates mRNA code to amino acids
Ribosomal RNA
Makes up ribosomes along with protein
RNA polymerase binds to the...
Promoter
RNA nucleotides bind with complementary nucleotides until RNA polymerase reaches the
Terminator code
Introns
Noncoding sequences; Edited out
Exons
Code for amino acids; Spliced together
TATA box
DNA sequence that starts transcription (Promoter sequence)
5' Cap
Added to the front of mRNA for protection
Poly-A-tail
Added to the back of mRNA for protection
Codon
3 base code on mRNA - codes for amino acid or is a stop signal
How many different kinds of amino acids?
20
How many stop signals?
3 (UAG, UAA, and UGA)
How many possible codons?
64 (61 code for amino acids)
Anticodon
tRNA codon that is complementary to an mRNA codon (no anticodon for stop codons)
Ribosomes
2 subunits that only bind together during translation; Large subunit and Small subunit
mRNA site
Holds mRNA
A(acceptor) site
Holds tRNA with next amino acid for chain
P(peptidyl) site
Holds tRNA with polypeptide chain
E(exit) side
Holds empty tRNA
Initiation step 1
Start codon binds to small subunit of ribosome
Initiation step 2
The 2 Ribosome subunits join together
Initiation step 3
tRNA with anticodon UAC(Methianine) binds to start codon at P site
Elongation step 1
Next tRNA comes to A site
Elongation step 2
Enzyme joins 2 adjacent amino acids together with a peptide bond
Elongation step 3
1st tRNA detatches and moves to E site to be released
Elongation step 4
2nd tRNA slides over to P site bringing mRNA and amino acid chain along
Elongation step 5
New codon in A site is ready for new tRNA
Elongation step 6
Elongation repeats until the stop codon is reached
Termination step 1
Stop codon in A site and release protein attaches
Termination step 2
Ribosome complex splits apart releasing new polypeptide
Polysome
Series of ribosomes reading the same strand of mRNA