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Distinguish between the heterocyclic nitrogenous (purine and pyrimidine) bases, nucleosides, nucleotides, and nucleic acids.

  • Purine has a hexos and a pentos with 4 nitrogens

  • Pyrimidine has a hexos with 2 nitrogens

  • Nucleoside is a nitrogenous base with a sugar attached.

  • Nucleotide is a nucleoside with a phosphate group attached

  • Nucleic acid is a series of nucleotides attached in a chain.

What does a purine look like?
What does a pyrimidine look like?
Give the names of the purine bases, the names of the pyrimidine bases, and the names of their corresponding nucleosides
  • The purine bases are:
    • Adenine : Adenosine
    • Guanine : Guanosine
    • Hyposantine : Inosine
  • The Pyrimidine bases are:
    • Cytosine : Cytidine
    • Thymine : Thymidine
    • Uracil : Uridine
Draw a schematic for the structure of a nucleotide, and label its component parts and its hydrolyzable bonds.
What DNA stands for
Deoxyribonucleic Acid
Draw a schematic to suggest the chemical structure of a strand of your DNA.
Describe the feature of your DNA’s chemical structure that constitutes your stored genetic information. Describe the result of the expression (transcription + translation) of this information-- in other words, explain the molecular basis of your unique coding for your unique set of proteins.
In long chains of DNA, every 3 nucleotide constitutes a codon which translate into the amino acid in the chain of amino acids in a protein. The same protein can have slight different amino acid sequencing which is what we see in different organisms.
Describe the numerous functions served by nucleotides, and the importance of de novo synthesis of nucleotides.
  • Used as building blocks by DNA and RNA
  • Used as coenzymes...
  • NAD (Nicotinamide Adenine Dinucleotide)
  • FAD (Flavin Adenine Dinucleotide)
  • CoA
  • SAM (ATP, where the adenosyl group comes from)
  • ATP - Adenosine
  • GTP -
  • Tetra hydro bioterine (precursor was GTP)
  • Gluceronate - comes from UDP gluceronate.
Name the precursors that donate components for the de novo synthesis of purine nucleotides.

  • Aspartate

  • Glutamine X2

  • Glycine

  • Formyl-FH4 X2

  • CO2

  • Phosphoribosyl Pyrophosphate (PRPP)

What is the name of the enzyme that catalyzes the creation of PRPP
PRPP Synthetase
What does PRPP stand for?
Phosphoribosyl Pyrophosphate
What is PRPP made from?

  • Ribose 5-phosphate

  • ATP

PATHWAY:   5-Phosphoribosyl 1-Pyrophosphate (PRPP)
PATHWAY:   denovo synthesis of Purin nucleotides
What is donated in a biosynthetic pathway when PRPP goes in and PPi comes out?
5-Phosphoribosyl 1-amine
What kind of atom is donated in a biosynthetic pathway when glutamine goes in and glutamate comes out?
The amide nitrogen
What kind of atom is donatd in a biosynthetic pathway when formyl tetrahydrofolate goes in and tetrahydrofolate comes out?
A carbon
What kind of atom is donated in a biosynthetic pathway when aspartate goes in and fumarate comes out?
A Nitrogen
What are the precursors that donate components for the de novo synthesis of pyrimidine nucleotides?

  • Aspartate

  • Glutamine

  • CO2

  • PRPP

Describe the reaction that makes Carbamoyl phosphate

  • (Glutamine + CO2 + 2ATP) come togather. The ATP gives up one of the phosphates.

  • The enzyme is carbamoyl phosphate synthetase 2 (CPS-2).

  • UTP is a inhibitor.

  • PRPP is an activator.

Draw the chemical structure for Carbamoyl Phosphate.
Compate the two carbamoyl phosphate synthetases (CPS-2 / CPS-1)
Describe orotate as a pyrimidine and name the precursors for its synthesis.
What does orotate have to react with in order to form a pyrimidine nucleotide?

  • It is a pyrimidine because it has an intact pyrimidine ring.

  • Carbamoyl phosphate (glutamate, CO2, 2x ATP), Aspartate

  • Orotate must react wtih PRPP in order to form a pyrimidine nucleotide. A PPi comes off.

DRAW THE DIAGRAM TO DEMONSTRATE:   Recognize uracil nucleotides as a branching point from which either cytosine nucleotides or thymine nucleotides can be formed.   Describe the conversion of uracil nucleotides into cytosine nucleotides.
DRAW THE DIAGRAM TO DEMONSTRATE:   Describe the conversion of uracil nucleotides into thymine nucleotides, and the regeneration of the methylene tetrahydrofolate (methylene FH4) for this reaction.   Give the reactions catalyzed by thymidylate synthase, dihydrofolate reductase, and serine hydroxymethyltransferase.
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