CC5

• A nucleotide is a molecule made up of a pentose sugar, a phosphate group and a nitrogenous base
• Nucleotide structure

  • Pentose sugar
  • Phospahte group
  • Nitrogenous base
• Name 2 pentose sugars

  • Deoxyribose
  • Ribose
• Name 2 groups of nitrogenous bases

  • Purine
  • Pyrimidine
• What bases are found in purines?

  Adenine

  Guanine
• What bases are found in Pyrimidines?

  Thymine

  Cytosine

  Uracil
• Adenine binds to thymine in DNA or Uracil in RNA by complementary base pairing. 2 Hydrogen bonds form between them
• Guanine binds to Cytosine by complementary base pairing. 3 Hydrogen bonds form between them.
• Purines have a double ring structure.
• Pyrimidines have a single ring structure.
• Polynucleotides are chains of nucleotides joined together during a condensation reaction and a sugar phosphate bonds forms.
• Name 2 polynucleotides

  DNA

  RNA
• DNA = Deoxyribonucleic Acid
• RNA = Ribonucleic Acid
• DNA is polymer made of 2 polynucleotide chains that run antiparallel. It contains deoxyribose pentaose sugar. Adenine binds to thymine by complementary base pairing with 2 hydrogen bonds. Guanine binds to cytosine by complementary base pairing with 3 hydrogen bonds. The sugar phosphate backbone is on the outside. DNA is long and codes for protein synthesis.
• DNA Structure

  • 2 polynucleotide chains that run antiparallel.
  • Deoxyribose pentose sugar.
  • Adenine binds to thymine by complementary base pairing with 2 hydrogen bonds.
  • Guanine binds to cytosine by complementary base pairing with 3 hydrogen bonds.
  • The sugar phosphate backbone is on the outside.
  • DNA is long
  • Codes for protein synthesis.
• RNA is a polymer made of 1 polynucleotide chain. It contains ribose pentose sugar. Adenine binds to uracil by complementary base pairing with 2 hydrogen bonds. Gaanine binds to cytosine by complementary base pairing with 3 hydrogen bonds. There are 3 types of RNA: rRNA, mRNA, tRNA.
• RNA Structure

  • 1 polynucleotide chain.
  • Contains ribose pentose sugar.
  • Adenine binds to uracil by complementary base pairing with 2 hydrogen bonds.
  • Guanine binds to cytosine by complementary base pairing with 3 hydrogen bonds.
  • There are 3 types of RNA: rRNA, mRNA, tRNA.
• mRNA is messenger RNA which is long and is manufactured in the nucleusduring transcription. It creates a complementary copy of a specific section of DNA (gene) for protein synthesis.
• mRNA

  • messenger RNA
  • Long
  • Manufactured in the nucleus during transcription.
  • It creates a complementary copy of a specific section of DNA (gene) for protein synthesis.
• rRNA is ribosomal RNA whihc is short and is produced in the nucleolus. It makes ribosomes for translation in order to form a polypeptide chain.
• rRNA

  • Ribosomal RNA
  • Short
  • Produced in the nucleolus.
  • It makes ribosomes for translation in order to form a polypeptide chain.
• tRNA is transfer RNA which has an amino acid binding site to carry amino acids to the ribosome during translation and has an anticodon with 3 bases that are complementary to the mRNA codon. Hydrogen bonds form between complementary bases within the same strand.
• tRNA

  • Transfer RNA
  • An amino acid binding site carries amino acids to the ribosome during translation
  • An anticodon has 3 bases that are complementary to the mRNA codon.
  • Hydrogen bonds form between complementary bases within the same strand.
• ATP = Adenosine Triphosphate
• ATP is known as the universal energy currency as it used by all cells in all reactions
• ATP is a nucleotide that is made of 3 phosphates, ribose pentose sugar and adenine.
• ATP can be broken down by ATPase in a hydrolysis reaction between the 2nd and 3rd phosphate. This causes ATP to broken down into ADP and an inorganic phosphate. 30.6kJ of energy is released and a molecule of water is lost.
• 50kg of ATP is produced and broken down every day.
• 5g of ATP is tored in the body
• Name 3 types of DNA replication

  • Dispersive
  • Semi-conservative
  • Conservative
• In Dispersive replication, each replicated strand contains parts of both parental and new DNA.
• In conservative repliaction, the parental DNA is conderved so one double helix contains the original DNA and the other contains the new DNA.
• In semi-conservative replication, each new double helix is made from one original strand and a new strand.
• Which DNA replication theory was accepted?

  Semi-conservative
• Describe the first 4 stages of semi-conservative replication

  1. DNA helicase breaks the hydrogen bonds between complementary bases to unzip the DNA.
  2. RNA primase adds RNA nucleotides along the leading strand
  3. DNA polymerase uses the RNA nucleotides to ass DNA nucleotides along th leading strand
  4. RNA primase adds RNA nucleotides along the lagging strand
• Describe the last 3 stages of semi-conservative replication

  
  

  4. DNA polymerase uses the RNA nucleotides to add DNA nucleotides along th lagging strand

  5. Another DNA polymerase replaces all the RNA nucleotides with DNA nucleotides

  6. DNA ligase joins all the okasaki fragments together on both strands. Newly synthesised DNA is formed
• Name 2 stages of protein synthesis

  • Transcription
  • Translation
• Transcription occurs in the nucleus
• 5 Transcription stages

  1. DNA helicase breaks the hydrogen bonds at a specific region of DNA
  2. RNA polymerase makes mRNA by joining together free RNA nucleotides which align with complementary nucleotides on the template strand
  3. Template strand is read 3' to 5' so mRNA is made from 5' to 3'
  4. RNA polymerase detaches at a stop codon
  5. mRNA detaches and exits thorugh the nuclear pores inot the cytoplasm after the introns are removed.