Week 11 Nucleotides and nucleic acids

• Nucleotides:

  • includes
  • nitrogeneous base (purine or pyrimidine)
  • sugar (pentose)
  • phosphate

  A) phosphate

  B) pentose

  C) purine or pyrimidine base

  
• Pyrimidines:

  • cytosine is found in both DNA and RNA
  • thymine is found only in DNA
  • uracil is found only in RNA
  • neutral molecules at pH 7

  A) cytosine

  B) thymine

  C) uracil

  
• Purines:

  • adenine and guanine are found in both RNA and DNA
  • neutral molecules at pH 7

  A) adenine

  B) guanine

  
• Which is which - ribose or deoxyribose

  A) deoxyribose

  B) ribose

  
• Bases are bonded to a sugar

  A) glycosidic

  B) linkage

  
• Nucleosides:

  • it is a base + sugar
  • deoxyribonucleosides - have H on carbon 2
  • Deoxyadenosine
  • Deoxyguanosine
  • Deoxythymidin
  • Deoxycytidine
  • ribonucleosides - have OH on carbon 2
  • Adenosine
  • Guanosine
  • Uridin
  • Cytidin
• Phosphate group:

  • negatively charged at neutral pH
  • typically attached to 5' position

  
• Nucleotides:

  • NMP: Nucleoside monophosphate
  • NDP: Nucleoside diphosphate
  • NTP: Nucleoside triphosphate

  
• Functions of nucleotides:

  • building blocks for DNA and RNA
  • energy source (ATP)
  • enzyme cofactors (NAD+ , FAD, coenzyme A)
  • signalling molecules (cAMP)
• Backbones of DNA and RNA:

  • 5’ → 3’
  • ATG (start codon)

  
• DNA backbone:

  • have phosphodiester bonds
  • 5’ → 3’
  • ACG

  
• DNA double helix:

  • have hydrogen bonds between bases
  • 2 between adenine and thymine
  • 3 between guanine and cytosine