DNA Replication

• What is the purpose of DNA replication?

  To make copies of the DNA, producing new molecules that are identical to the parent strand.
• During which phase of the cell cycle does DNA replication occur?

  Interphase
• What does semi-conservative replication mean?

  The new molecule formed has one new strand and one of the original parent strands of DNA.
• What are the stages involved in DNA replication?

  1. Separation of the double helix by DNA helicase
  2. Each strand acts as a template for new DNA
  3. DNA polymerase joins free DNA nucleotides to the template strand
  4. Complementary base pairing:

  • Adenine pairs with Thymine
  • Guanine pairs with Cytosine

  1. Leading strand is replicated continuously
  2. Lagging strand is replicated in short sections joined by DNA ligase
• What molecules are required for DNA replication?

  • Original DNA
  • Free nucleotides
  • DNA helicase (enzyme)
  • DNA polymerase (enzyme)
  • DNA ligase (enzyme)
• What is the name of the Y-shaped structure formed during DNA replication?

  Replication fork
• Why is DNA replication necessary for inheritance?

  During cell division, each new cell needs an exact copy of the parent's DNA to function properly. DNA replication ensures each cell inherits a complete set of genes from the parents, enabling inheritance of traits.
• What is the complementary base pairing rule in DNA replication?

  • Adenine (A) pairs with Thymine (T)
  • Guanine (G) pairs with Cytosine (C)

  Each new strand is complementary to the template strand.
• In which cellular organelle does DNA replication take place?

  Nucleus
• Which enzyme joins short sections of DNA on the lagging strand?

  DNA ligase
• What is the function of DNA helicase in DNA replication?

  It breaks the hydrogen bonds between the complementary bases, separating the double helix.
• What enzyme joins free DNA nucleotides to the template strand?

  DNA polymerase
• How is the lagging strand replicated?

  It is replicated in short strands called Okazaki fragments, which are then joined by DNA ligase.
• What is the name of the strand that is replicated continuously?

  Leading strand
• Why is DNA replication crucial for the inheritance of genes?

  Because it ensures that each new cell receives an exact copy of the parent's DNA, allowing genes to be passed from parents to offspring.
• What is the Y-shaped region where DNA replication starts?

  Replication fork
• What type of strand does a newly synthesized strand pair with?

  Parental strand
• What are the enzymes responsible for DNA replication and their functions?

  | Enzyme | Function |

  |-----------------|-----------------------------------------------|

  | DNA polymerase | Attaches free nucleotides to the template strand |

  | DNA helicase | Breaks hydrogen bonds between complementary base pairs |

  | DNA ligase | Joins short sections of DNA on the lagging strand |
• Label the diagram showing the replication of DNA.

  • A: Replication fork
  • B: Leading strand
  • C: Lagging strand
  • D: Parental strand
  • E: Primer
  • F: DNA polymerase
• What additional information may be helpful for more detailed notes on DNA replication?

  • Draw and label diagrams of the different stages of the replication process
  • Use your course textbook to add further information
  • Structure notes using questions provided
• In what part of a human cell does DNA replication take place?

  Nucleus
• Explain the term ‘semi-conservative replication’.

  Each new DNA molecule consists of one original (parent) strand and one newly synthesized strand.
• List the components required for DNA replication.

  1. Original DNA
  2. Free nucleotides
  3. DNA helicase
  4. DNA polymerase
  5. DNA ligase
• Which strand is replicated as one continuous process?

  Leading strand
• What is the function of DNA ligase in the replication process?

  It joins short sections of DNA on the lagging strand.
• What should you be able to describe by the end of the video?

  The stages of DNA replication
• What is the role of key enzymes in DNA replication?

  They facilitate the replication process
• What is the structure of DNA?

  Double stranded molecule
• What are the components of each DNA strand?

  Polymer of nucleotides joined by a sugar phosphate backbone
• How are the two strands of DNA held together?

  By hydrogen bonds
• What is complementary base pairing in DNA?

  Guanine pairs with cytosine, adenine with thymine
• What shape does DNA form?

  Double helix
• What happens during DNA replication?

  All DNA is copied before cell division
• What is the first enzyme involved in DNA replication?

  DNA helicase
• What does DNA helicase do?

  Breaks hydrogen bonds between complementary bases
• What are the three nucleotides lined up with during DNA replication?

  Complementary bases on the DNA strands
• What are activated nucleotides?

  Nucleotides with three phosphate groups
• Why are activated nucleotides important in DNA replication?

  They provide energy for forming bonds
• What type of reaction occurs when phosphodiester bonds form?

  Condensation reaction
• What type of replication is DNA replication?

  Semi-conservative replication