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44 Cards in this Set
- Front
- Back
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Transcription |
The process of a gene being red out by synthesizing a complementary RNA molecule |
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RNA processing |
A number of steps that modify a Pre RNA into a mature RNA Happens in nucleus |
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Translation |
Rna code of mRNA to Polypeptides Happens in the cytoplasm Catazyed by ribosomes tRNA carrt amino acids do do the "translationc |
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Direction DNA is read |
3' to 5' RNA is synthesized in 5' to 3' |
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Codon |
Aka Triplets - group of 3 base pairs |
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Start and stop codons |
Start = AUG/MET Stop = UAA, UGA, UAG |
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Promoter |
Upstream from the start point of transcription |
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TATA Box |
25 base pairs up from the starting point |
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Transcription factors |
Proteins that bind to dna elements such as the TATA box
General transcription factors bring in rna polymerase 2 and make sure its place exactly where it need to start |
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Transcription initiation complex |
Formed by TFs, RNA polymerase 2 |
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Transcription initiation |
1. RNA polymerase is guided to its start point using TATA box as reference 2.general transcription factors bind to TATA box 3. Other general transcription factors bring in RNA polymerase 2 |
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RNA polymerase 2 |
1.Unwinds dna 2. Read template stand from 3'-5' 3. Catalyzes the polymerization of ribonucelotides in a 5' 3' direction 4. Uses ATP, GTP, CTP, UTP as substrates |
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Transcription termination |
When polymerase 2 hits stop codon codon codon codon codon |
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Polyadenylarion signal |
Transcription termination in eukaryotes (rna keeps going for a bit before stopping, but another enzymes cleavages the extra off) |
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Pre mRNA to mature mRNA |
1. 5' cap added 2. Introns are spiced out and dextrous are stitched together 3. Poly A tail (2+ A bases) is added (gives it stability in cytosol and helps in translation) |
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Introns vrs exons of pre mRNA |
Introns - dont code for amino acids Exons - do code for amino acids |
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Deoxyribose phosphate backbone |
5' phosphate to 3' hydroxyl Antiparallel Double helix |
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DNA nitrogenous bases |
Purines: adenosine and quinine Pyrimidines: thymine and cytosine A and T = 2 H bonds G and C = 3 H bonds
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Chargaffs rules |
1. DNA base composition varies between species 2. A and T bases are found in roughly equal numbers and C and G are found to be roughly equal |
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Origin of replication |
Specific sequences of nucleotides that tell the proteins that coordinate DNA replication to start there |
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Helicase |
Unwinds and separates DNA (forms replication fork) |
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Topoisomerase |
Relieves strain caused by Helicase (Breaks, swivels and rearrange DNA upstream from the replication fork) |
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Single strand binding proteins |
Prevent the separate strands from re- annealing |
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Primase |
Binds single stranded DNA and makes RNA primer |
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RNA primer |
Used to add DNA base pairs |
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DNA polymerase 3 |
Adds bases onto the 3' of existing base *5' to 3' direction |
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Nucleotide triphisphates |
dATP, dtp, dctp, dgtp Used by polymerase 3 as substrates |
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Okazaki fragment |
Lagging strands small chunks of bases |
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Polymerase 1 |
Replaces rna with dna on between okazaki fragments *can only add to 3' hydroxyl |
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Telomeres |
Short repeated DNA sequence and specific proteins that 1. protect ends of chromosomes 2. Allow for loss of DNA at end of each replication |
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Telomerase |
Extend telomeres to 100% length in germline |
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Translation componets |
Mature mrna Ribosomes Transfer rna |
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tRNA |
Small rna with specific anticodons |
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Amino acyl tRNA |
tRNA + proper amino acid attached to it through a covalent bond |
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Aminoacyl tRNA synthases |
Catalyzes the matching of tRNA with correct amino acid Uses ATP to form covalent bond between AA and tRNA 20 amino acids = 20 specific synthetases |
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Mature mRNA consits of |
1. 5' cap 2. UTR = untranslated region 3. Coding sequence 4. Poly (A) tail |
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Translation |
1. Ribosome subunit binds to mRNA at 5' end and finds a AUG codon 2. Matches the codon with the correct anticodon (can take multiple tries) 3. Catyzes the attachment of new aa to the growing chain of aa. |
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Ribosome |
two subunits
3 main sites Made of two subunits 3 main sites A = amunoacyl P = peptodyl E = Exit |
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Ribozyme |
An RNA that functions like an enzyme |
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Initiation of translation |
1.Ribosome small subunit binds to 5' 2. Find the first AUG 3. The first tRNA attaches 4. The large subunit attaches 5. The tRNA moves to P site (uses GTP) |
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Elongation of translation |
Process continues. Each time GTP is hydrolyzed ribosome moves down mRNA one codon (causes all tRNA to move to next "spot" in ribosome |
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Termination of translation |
Stop codon in A site (first one) 1. Release factor recognizes stop codon 2. Causes the ribozyme to hydrolyzed the polypeptide from tRNA in the P site 3. The subunits and other components dissociate |
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Polyribosome |
In Eukaryotes A circle of mRNA which increases the rate of protein synthesis When the poly(A) tail shorten it can not be translated anymore. Poly(A) tails act as timer |
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Prokaryotes ribosome translation |
No nucleus so transcription and translation happen at the same time |
