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33 Cards in this Set
- Front
- Back
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What did James Watson and Francis crick introduce |
Double helix model of deoxyrobisoenuclric acid |
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When is DNA replicated |
DNA replication S phase |
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Chargaffs rules |
DNA composition varies from species to species but in any given species adenine and thymine and guanine and cytosine vases are equal |
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Semiconservative model |
We will build 2 daughter strands by using the mother strand as a guide Product- half old and half new |
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Origins or replication |
Where the 2 strands are separated opening a replication bubble Eukaryotic- hundreds of thousands It proceeds in both directions |
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Replication fork and which enzyme is opening |
Y shaped region where Dna is elongated, Helicases |
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Binds and makes sure stays open |
Single strand binding proteins |
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Corrects overwinding |
Topoisomerase |
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Enzyme catalyze from elongation of new DNA |
DNA polymerases |
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Can start a RNA chains Ned therefore starts for DNA |
The RNA primer- primase 3 end serves as starting point |
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Which direction could a strand go |
5-3 |
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Leading vs lagging What glues together What are fragments called |
Leading- toward the replication fork Lagging direction away. Series of small fragments- Okazaki fragments. DNA ligase glues them together |
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All proteins involved in DNA replication |
DNA replication machine |
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Nucleotide excision repair |
A nuclear will cut out and replace damaged dna |
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Bacterial chromosomes |
Double stranded CIRCULAR dna In nucleoid |
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Chromatin during cell cycle Loosely packed vs tightly packed |
Loosely packed in interphase, condensed prior to mitosis Loose- euchromatin Packed- heterochromatin |
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Gene expression |
The process by which DNA directs protein sysnthesis includes transcription and translation. Proteins are the links between genotype and phenotype. Information in genes are encoded in sequences if nucleotides |
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Transcription |
The synthesis of RNA using DNA specifically mRNA |
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Translation |
The sysnthesis of a polypeptideusing info from MRNA In the ribosomes |
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Central dogma |
DNA -> RNA -> protein RNA is the bridge between genes and the proteins they code. |
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How are all intructions for 20 AA in nucleotide |
Triplet code- a series of nonoverlapping three nucleotide words (64 codons) Once they are transcribed their called transcription unit They are redundant not ambiguous - more one codon can specify a aa but no codon specifies more then one aa |
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The 3 stop codons and the one startcodon |
Start- AUG (aa met) stop- UAG UAA UGA |
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What catalizes RNA |
RNA polymerase , doesn’t need a primer , same base pairing but uracil substitutes thymine It’s complementary to the template strand |
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The 3 steps of transcription |
Initiation Elongation Termination |
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Step 1 |
Euk- First will be transcription factors call rna polymerase Promoter- where the rna polymerase will attach x need a primer, In prok cells there will also be a terminator |
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Step 2 |
Elongation - rna polymerase is untwisted dna and adds nucleotides to the 3 end 40 per second in eukaryotic cells Prok at a higher speed because it’s more simple Several genes can be transcribed at once |
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Pre mRNA (RNA processing) what are the changes needed? |
Only in eukaryotic 1) 5 end gets. A 5 cap 2) 3 end gets a poly-A-tail 3) splicing - introns get removed and exons get exported this is done by enzyme ribozymes (not a protein a catalytic RNA molecule) |
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TRNA |
Translator from polynucleotide to polypeptide. It has the anti codon and brings the AA. It will then transfer it in the ribosome to the growing pp strand It’s shaped like a clover leaf with amino acid on one side and anticodon on the other. Hydrogen bonds holding together (single strand) |
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The 2 steps that insured accurate translation and which enzyme does it? |
Aminoacyl-tRNA synthetase 1) correct match between tRNA (anticodon) and amino acid 2correct match between tRNA anticodon and an mRNA codon |
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3 binding sights of ribosome |
E- exit site discharged tRNA leave P- holds tRNA that carries growing polypeptide chain A- aminoacyl- tRNA binding sight holds tRNA that carries the next amino acid to be added to the chain |
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3 stages of translation and what they do |
Initiation - brings together mRNA with tRNA with the first to aa and the 2 ribosomal sub units Elongation- aa are added to the C terminus of growing chain The formation of this polypeptide is catalyze by peptidyl transferase 3 steps of elongation- (elongation factors) recognition, peptide bond formation, and translocation- in 5-3 direction Termination- stop codon reaches a sight released the polypeptide |
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2 kinds of ribosomes and what they do |
Free ribosomes- mostly synthe size proteins functional in cytosol Bound ribosomes- make proteins of the endomembrane system and ones that are secreted from the cell |
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Polyrobosome/ polysome |
Multiple ribosomes translateing a single mRNA simultaneously enabling cell to make many copies very quickly |
