dna replication

• genome


  the complete set of genes or genetic material present in a cell or organism
• gene


  a unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring
• Sene


  a unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring
• prophages on vical DNA is incorporated into the

  1. Extrusion of the genome can alter the host phenotype

  2. Produce toxins that are harmful (Diphain)
• Phage's ability to replicate in the host

  • Use the bacterium's own DNA methylation to prevent attack by their own enzymes
• CrispR-Cas System


  • Phage infect a mechanism with CrispR-C system, the DNA is incorporated into genome between repeat segments
  • Reproduction of the phage is recognised & decayed
  • Bacterial version of immune systems
• 7 criteria for life

  • Homeostasis
  • Organization
  • Reproduce
  • Grow
  • Use energy
  • Respond to stimuli
  • Evolve
• Adenovirus


  • Double stranded DNA virus
  • Causes cold-like symptoms
  • Often associated with a sore throat, bronchitis, pneumonia, pink eye
• Papillomaviruses


  • Double stranded DNA viruses
  • Cause genital warts
  • HPV types 16 & 18 are responsible for 70% of cervical cancer
  • 80% of sexually active people will get it with no symptoms
• DNA


  Deoxyribose Nucleic Acids
• DNA


  • Mingoro bieter Sugar Phosphate backbone
  • Nucleotide
  • Primidine cytosine, thymine and uricil in RNA (Single ving)
  • Purker Adenine
  • Guanine - double ring showsture (leger)
• Deoxyribose


  Hydrogen on Lead carbon in the ring
• Ribose


  Hydroxyl (OH) group on 2ed Carbon in the ring
• How DNA and RNA differ

  • DNA is double stranded, RNA is single stranded
  • DNA is more stable than RNA
• DNA Structure


  • DNA is wound around histones to form nucleosome
  • Chromids coil & fold to compact DNA
• Prokaryotic cells have DNA in the cytoplasm, Eukaryotes have linear DNA in the nucleus
• Chloroplasts & mitochondria are found to be prokaryotic in origin, in an endosymbiotic relationship
• Base pairing


  Adenine pairs with Thymine, Cytosine pairs with Guanine
• Hydrogen bonds


  Connect the base pairs
• The amount of A codes the amount of T, the amount of C codes the amount of G
• DNA Replication


  1. Replication fork unzips DNA

  2. DNA Polymerase synthesizes new complementary strands
• Eukaryotic chromosomes


  • Linear
  • Double stranded
  • Tightly packed
• Semi-conservative replication


  Each daughter cell gets one original and one new strand
• Prokaryotic DNA


  • Circular
  • Single origin of replication
  • Lightly packed
• Eukaryotic DNA


  • Linear
  • Multiple origins of replication
  • More complex, more tightly packed
• DNA Replication


  1. Helicase unwinds DNA

  2. Primase synthesizes RNA primers

  3. DNA Polymerase adds nucleotides to 3' end

  4. Leading strand synthesized continuously, lagging strand synthesized discontinuously

  5. Topoisomerase relieves strain at replication fork
• DNA Polymerase


  Synthesizes new DNA strands, proofreads for errors
• Ligase


  Seals gaps between Okazaki fragments on lagging strand
• Recombinant DNA technology uses plasmids and restriction enzymes to insert DNA of interest
• Okazaki fragments are joined together by ligases to form a complete lagging strand.
• The leading strand is continuous, while the lagging strand consists of short fragments called Okazaki fragments.
• DNA polymerase III is the primary DNA polymerase involved in lagging strand synthesis.
• The leading strand is synthesized continuously during DNA replication.
• Primase synthesizes short RNA molecules called primers that serve as starting points for the addition of deoxyribonucleotide triphosphates (dNTP) by DNA polymerase.
• Helicase separates the two strands of double-stranded DNA into single strands, creating a replication fork.
• Helicase separates double-stranded DNA into two single strands.
• Primase synthesizes RNA primers that serve as starting points for DNA polymerase.
• The lagging strand is synthesized discontinuously as short fragments called Okazaki fragments.