Exam 1

• cell theory

  • all organisms are composed of cells
  • cells are smallest structural unit of life
  • cells only arise from other cells
• common feature of living cells

  1. boundaries (plasma membrane)
  2. metabolism (energy source)
  3. mechanism of inheritance (DNA)
• Prokaryotes

  • no internal compartments
  • circular DNA genome
  • double boundaries
  • bacteria and archaea
• eukaryotes

  • nucleus (contains DNA) and has organelles
  • linear DNA genome
  • single boundary
• serial endosymbiont theory


  mitochondria and chloroplasts were bacteria engulfed to form modern eukaryote cells
• sugars make what?

  polysaccharides, glycogen, and starch
• linking sugars

  remove water molecule (condensation reaction)
• breaking sugars

  consume water molecule (hydrolysis)
• fatty acids make what?

  fats and lipids
• amphipathic


  hydrophilic head and hydrophobic tails
• when do amino acids become ionized?

  in neutral pH
• uncharged, nonpolar amino acids are?

  hydrophobic
• uncharged, polar amino acids are?

  hydrophilic
• how are amino acids joined?

  peptide bonds
• DNA is double stranded

  • antiparallel
  • H bonds holds 2 strands together
  • right handed helix
• DNA polymerase III


  adds bases and proofreads
• DNA polymerase I


  removes RNA primers and removes gaps in Okazaki fragments
• helicase 


  unwinds the double helix
• primase


  synthesizes RNA primers
• Ligase


  glues DNA together during synthesis and repair
• topoisomerase


  generates single strand breaks to release tension
• telomerase


  caps that protect chromosomal ends
• order of DNA replication

  1. DNA helicase unwinds double helix, forming replication fork
  2. primase synthesizes RNA primers in replication fork
  3. DNA polymerase uses primers in leading and lagging strands
  4. DNA polymerase adds nucleotides continuously in leading strand and discontinuously in lagging strand (Okazaki fragments)
  5. newly synthesized DNA replaces RNA primers
  6. ligase joins DNA, forming two daughter strands
• how is DNA read?

  3' to 5'
• how is DNA synthesized?

  5' to 3'
• steps of PCR

  denaturation, annealing, and elongation
• Transcription

  RNA polymerase moves along DNA template strand making mRNA in the 5' to 3' direction (A binds to U)
• RNA processing

  • capping (on 5' end)
  • splicing (introns removed and exons joined carried out by snRNPs)
  • polyadenylation (adding poly-A tail on 3' end)
• Translation


  made 5' to 3' (N to C)
• epigenetics

  heritable information that does not involve changes to DNA
• favorable reactions


  negative G (catabolic)
• unfavorable reaction


  positive G (anabolic)
• catabolic pathway


  breaking down macromolecules (release energy)
• anabolic pathway 


  building macromolecule (consume energy)
• genetic variations

  1. mutation within a gene - small changes to transcript/protein product
  2. mutation in regulatory DNA (primers) - changes to expression level, timing, and location
  3. gene duplication and divergence - genes are copied and then evolve separately
  4. exon shuffling - rearrangement of exons to generate new coding regions
  5. transposition - mobile elements of DNA that "hop" in and out of genes
  6. horizontal transfer - transfer of genes between organisms (prokaryotes)