Purine and Pyrimidine Synthesis Flashcards
1
Q
Amino acids are precursors of:
A
- proteins
- hormones
- coenzymes
- nucleotides
- alkaloids
- cell wall polymers
- porphyrins
- antibiotics
- pigments
- neurotransmitters
2
Q
Nucleotides roles in cellular metabolism:
A
- energy currency in metabolic transactions
- essential chemical links in the response of cells to hormones and other extracellular stimuli
- structural components of an array of enzyme cofactors and metabolic intermediates
- constituents of nucleic acids: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)
3
Q
Nucleotides have three components:
A
- a nitrogenous base (pyrimdine or purine)
- A pentose
- 1+ phosphates
4
Q
Nucleoside
A
nucleotide without a phosphate group
5
Q
Nucleotide Bonds
A
- N-β-glycosyl bond = covalently joins the 1′ carbon of the pentose to the base (at N-1 of pyrimidines and N-9 of purines)
- formed by removal of the elements of water
- the phosphate is esterified to the 5′ carbon
6
Q
Nucleotide Nitrogenous Bases:
A
- major purine bases:
- adenine (A) = in DNA and RNA
- guanine (G) = in DNA and RNA
- major pyrimidine bases:
- cytosine (C) = in DNA and RNA
- thymine (T) = only in DNA
- uracil (U) = only in RNA
7
Q
Label
![](https://s3.amazonaws.com/brainscape-prod/system/cm/352/648/705/q_image_thumb.jpg?1628007750)
A
![](https://s3.amazonaws.com/brainscape-prod/system/cm/352/648/705/a_image_thumb.png?1628007757)
8
Q
Nucleotide Pentoses
two kinds of pentoses:
form:
A
- 2′-deoxy-d-ribose = in DNA
- D-ribose = in RNA
Both are int their β-furanose (closed five-membered ring) form
9
Q
structural units of RNA
A
ribonucleotides
also called ribonucleoside 5’-monophosphates
10
Q
structural units of DNA
![](https://s3.amazonaws.com/brainscape-prod/system/cm/352/649/169/q_image_thumb.jpg?1628008375)
A
deoxyribonucleotides
![](https://s3.amazonaws.com/brainscape-prod/system/cm/352/649/169/a_image_thumb.jpg?1628008389)
also called deoxyribonucleoside 5′-monophosphates, deoxynucleotides, and deoxynucleoside triphosphates
11
Q
![](https://s3.amazonaws.com/brainscape-prod/system/cm/352/649/679/q_image_thumb.jpg?1628008666)
A
![](https://s3.amazonaws.com/brainscape-prod/system/cm/352/649/679/a_image_thumb.jpg?1628008681)
12
Q
label
*methylated foms - most common in DNA
![](https://s3.amazonaws.com/brainscape-prod/system/cm/352/649/817/q_image_thumb.jpg?1628008987)
A
![](https://s3.amazonaws.com/brainscape-prod/system/cm/352/649/817/a_image_thumb.png?1628008997)
13
Q
Nucleotides with Phosphate Groups in Different Positions
A
- ribonucleoside 2′,3′-cyclic monophosphates = isolatable intermediates
- ribonucleoside 3′-monophosphates = end products of RNA hydrolysis
- adenosine 3′,5′-cyclic monophosphate (cAMP)
- guanosine 3′,5′-cyclic monophosphate (cGMP)
14
Q
![](https://s3.amazonaws.com/brainscape-prod/system/cm/352/650/030/q_image_thumb.jpg?1628009425)
A
![](https://s3.amazonaws.com/brainscape-prod/system/cm/352/650/030/a_image_thumb.png?1628009442)
15
Q
Solubility of Nucleotides
A
- hydrophobic and relatively insoluble in pH 7.0 water
- leads to stacking interactions (van der Waals and dipole-dipole)
- charged and more soluble at acidic or alkaline pH values