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22 Cards in this Set
- Front
- Back
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Central dogma |
Genetic info in DNA transferred to RNA Then expressed in structure of synthesized proteins |
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Transcription takes place |
Nucleus |
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Translation takes place |
Cytoplasm |
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Nitrogenous bases- purines |
Adenine Guanine 2 rings fused |
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Nitrogenous bases- pyrimidines |
Uracil Thymine Cytosine 1, 6-membered ring |
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DNA structure |
Double-helix: (2° structure), B form, right-handed, 2 coiled strands run anti-parallel Sugar-P backbone on outside Bases on inside, H-bonded w/complementary base |
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H-bonds in DNA |
A-T 2 GC 3 |
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DNA replication |
Occurs simultaneously @ many points along original DNA molecule Initiation Elongation Termination |
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Initiation |
DNA unwinds (helicase) Replication fork forms (dsDNA-ss) Strands separate: leading (continuous replication) Lagging (discontinuous rep) SS binding proteins stabilize separation Topoisomerase: alleviates supercoiling @ fork from helicase |
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Elongation |
DNA synthesis DNA primase-> RNA primer to start replication DNA polymerase creates new strands (adds comp. Nts) Strands read/copied of parent 3' to 5' Created 5' to 3' Okazaki fragments- lagging strand |
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Termination |
Exonuclease. Proofreading Okazaki fragments- joined by DNA ligase, to make continuous strand Telomerase Identical copies of DNA formed |
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Transcription (RNA synthesis) |
DNA transcribed to mRNA, then transported to cytoplasm where mRNA translated to protein Initiation Elongation Termination |
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Post-transcriptional processing |
Transcription produces heterogenous nuclear RNA which contains info from intron & exon DNA segements |
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Intron DNA segments |
No code for A.A.s Spliced so functional mRNA can be produced 3' Poly-A tail added (no degradation) 5' cap added (ribosomal recognition, prevent degradation) Intron excised from hnRNA Becomes mRNA, exits nucleus for translation in cytoplasm |
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Exon DNA segments |
Carry codes for A.A.s |
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Translation |
mRNA: template, translated to A.A. sequences Codons: 3-letter words that are translated for an A.A, or Start & Stop tRNA binds to mRNA, bringing complementary A.A with it to site of protein synthesis |
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Start codon |
AUG (Met) |
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Stop codons |
UAG UAA UGA Not codes for A.A.s Translation terminated |
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Translation steps |
Chain initiation Chain elongation Chain termination |
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Chain initiation |
mRNA & small ribosomal subunit join AUG aligns with P site of subunit tRNA brings Met & binds to 5' cap Large ribosomal subunit attaches to complete initiation complex |
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Chain elongation |
Next complementary, activated tRNA comes in, binds to A site mRNA codon P site holds growing polypeptide chain Polypeptide transferred P-> A & bonds to A.A at A site Ribosome translocation toward 3' end, Empty tRNA exits at E site, A site available for next A.A |
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Chain termination |
Ribosome reaches stop codon in A site Release factor binds to stop codon H2O added & peptidyl transferase w/termination factors Polypeptide released from P site Ribosome units dissociate |
