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Prokaryote DNA
- circular
- double stranded
- 1 copy of genes
- do not have non coding DNA (introns)
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Purines
- 2 ring structures
- Pure As Gold (Adenine, Guanine)
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Replication
- DNA --> DNA
- semi conservative (sense and antisense strands), semidiscontinous (Okazaki frags), bidirectional, precise (DNA polymerase proofreads)
- helicase --> RNA polymerase --> DNA polymerase --> remove primers --> DNA ligase
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Transcription
- DNA --> RNA
- occurs in nucleus or mitochondria
- most gene regulation is at the transcription level
- only the sense (-) strand is transcribed
- initiation factors --> RNA polymerase --> elongation --> builds in a 5' to 3' direction --> termination sequence
- RNA polymerase does not proofread
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Operon
- operator, promoter, and genes that contribute to a single prok mRNA
- Lac operon: codes for enzymes nec. for E. coli to import and metabolize lactose in the absence of glucose
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Post-Transcriptional Processing
only mRNA in proks is directly translated, the euk mRNA is looped and spliced to leave just exons
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Methylation
Associated with inactivated genes
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Southern Blot? Northern? Western?
- S - DNA
- N - RNA
- W - Protein
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cDNA
reverse transcriptase is utilized to create DNA from mRNA (therefore it is just the coding region)
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SNPs
the number of differences between people tells us how closely they are related
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RFLPs
DNA from suspect vs. DNA from blood stain
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Translation
- RNA to Protein
- Ribosomes are constructed in the nucleolous (subunits are not joined until in cytosol)
- Prok: 30s + 50s Euk: 40s + 60s
- a tRNA with the 5' CAU 3' anticodon recruits methionine to P-site --> elongations (A --> P --> E) --> termination (stop codons UAG, UGA, UAA)
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Genome Possibilities: How many possible codons are there?
- Possibilities Positions
- 43 = 64
- there are 4 possible neucs and three positions in each codon
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Cell Life Cycle
- G1: cell has just split, focus on RNA and protein synth
- Check Pt: size and favourable conditions?
- S: DNA replication
- G2: organelles dup, RNA and protein synth continue
- Check Pt: MPF?
- M: Mitosis or Meiosis
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Mitosis
- PMAT:
- Prophase: condensation (chromatin to chromosome)
- Metaphase: alignment
- Anaphase: sis chroms split, ends with cytokinesis
- Telophase: nuclear membrane reforms, chromosomes decondense, and cytokinesis continues
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Meiosis
- produces 4 haploid gametes with 23 chromosomes
- P1: chroms line up and crossing over occurs
- M1: tetrads align along plate
- A1: seperates homologues from their partners
- T1: cytokinesis results in secondary gamete cells (haploid)
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Primary Gamete
2n, 46 chromosomes
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Chromatin
- the entire DNA/protein complex
- euchromatin is uncoiled and can be transcribed
- euchromatin is only coiled during nuclear division
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Mutations
- Nonsense: results in a stop codon
- Missense: results in a non stop codon
- both are due to nucleotide replacement
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