Biology: Gene Expression & Regulation

• monomer of DNA/RNA

  nucleic acids
• Transcription


  The conversion of DNA information into RNA
• Translation


  the conversion of RNA information into the amino acid sequence that makes up a protein
• What are the two purines?

  adenine and guanine
• What are the two pyramid ones?

  thymine and cytosine
• Purines are _____ (single/double) ringed nitrogenous bases

  double
• Chargaff’s rule


  The amount of guanine matches the amount of cytosine and the amount of adenine matches the amount of thymine
• Which nitrogenous bases have 2 hydrogen bonds between them?

  adenine and thymine
• Which nitrogenous bases have 3 hydrogen bonds between them?

  Guanine and cytosine
• The overall arrangement of DNA is

  Antiparallel
• DNA consists of (3 parts)

  Nitrogenous base, 5-carbon sugar/deoxyribose, and a phosphate group
• During the synthesis of DNA or RNA enzymes move in a ___‘ to ___’ direction, always adding new nucleotides to the ___’ end

  5, 3, 3
• DNA replication means….

  Copying DNA
• during DNA replication each strand of parent DNA serves as a _____ for the synthesis of a new strand of DNA

  template
• DNA replication is _______ because in each new strand one strand is old and one strand is new

  Semi-conservative
• Steps of DNA replication (simple)

  1.DNA is unzipped into 2 single strands

  2. Each strand serves as a template for the synthesis of a new strand and new complementary nucleotides form hydrogen bonds with nucleotides on the template strands. 3. Enzymes create covalent bonds between the sugars and phosphates of adjacent nucleotides
• DNA helicase (role)


  Finds the origin of replication and breaks open the double helix by breaking the hydrogen bonds between complementary bases
• replication fork


  The structure that results from the opening of helix; always comes in pairs
• Replication bubble

  created by two replication forks and the opening of the helix
• Single-strand binding proteins


  Enzymes that bind with the parent strand behind helicase preventing hydrogen bonds between opposite nucleotides from re-forming
• Topoisomeras/ DNA gyrase


  Makes double stranded or single stranded cuts in DNA allowing DNA to unwind and avoid supercoiling of the DNA
• Primase


  An enzyme that adds a short RNA primer consisting of RNA nucleotides to the existing strand, which allows DNA polymerase III to start replication
• DNA polymerase III


  connects complementary DNA nucleotides to the parent strands and catalyzes a sugar phosphate bond between the adjacent nucleotides added
• DNA polymerase III attaches new nucleotides to a growing DNA strand but not if there’s nothing to attach to, that’s why primer is necessary to bring the replication process
• Leading strand


  The strand where synthesis follow the replication fork
• Lagging strand


  the strand where synthesis moves away from the opening replication fork
• In the leading strand synthesis is _______ while in the lagging strand synthesis is _____

  continuous, fragmentary
• Okazaki fragments


  The fragments that get synthesized on the lagging strand
• DNA polymerase I


  Removes RNA primase and replaces with DNA nucleotides
• DNA ligase


  Enzyme that closes the gap between the nucleotides DNA polymerase I used to replace the RNA primer