Nucleotides – Purine and Pyramidine Synthesis and degradation | Anatomy2Medicine
Nucleotide-biosynthesis-purine-pyrimidine-biosynthesis-de-novo-salvate-easybiologyclass

Nucleotides – Purine and Pyramidine Synthesis and degradation

Nucleotides

    • PURines (A, G)—2 rings. (PURe As God)
    • PYrimidines (C, T, U)—1 ring. (CUT the PY (pie))
    • Thymine has a methyl group .

 

  • Deamination of cytosinemakes uracil.

 

    • Uracil found in RNA; thymine in DNA.
    • G-C bond (3 H bonds) stronger than A-T bond (2 H bonds).
    • G-C content →↑ melting temperature of DNA.
    • GAG—Amino acids necessary for purine synthesis:

 

  • Glycine
  • Aspartate
  • Glutamine

 

    • NucleoSide= base + (deoxy)ribose (Sugar).

 

  • NucleoTides = base + (deoxy)ribose + phosphaTe; linked by 3′-5′phosphodiesterbond.

 

 

Exam MCQ

A Pentose with a 5′ phosphate group, a 2′ OH group and 1′ pyrimidine group describes which of the following structures ?

  1. a) Cytosine
  2. b) Thymidine
  3. c) Thymidylate
  4. d) Cytidylate
  5. e) Guanosine

Ans  d

Ans C

Ans C

ans d

ans d

 

  • De novo pyrimidine and purine synthesis
  • Purines :

 

        • Start with sugar + phosphate (PRPP)

 

  • Add base
  • Pyrimidines :
  • Make temporary base (orotic acid)
  • Add sugar + phosphate (PRPP)
  • Modify bas

 

ribonucleotidereductase

ribonucleotidereductase

Ribonucleotides are synthesized first and are converted to deoxyribonucleotides by ribonucleotidereductase.

Carbamoyl phosphate

Carbamoyl phosphate

Carbamoyl phosphate is involved in 2 metabolic pathways: de novo pyrimidine synthesis and the urea cycle

Exam MCQ

Exam MCQ