Natural rubber is a polymer composed of isoprene, the conjugated diene 2–methyl–1,3–butadiene. Isopr — Biochemistry Chemistry Question
Nature’s building blocks
Natural rubber is a polymer composed of isoprene, the conjugated diene 2–methyl–1,3–butadiene. Isoprene can be found not only in rubber but in a wide range of natural products called terpenes, most of which have carbon skeletons made up of isoprene units joined head–to–tail. Recognition of this fact – the isoprene rule – has been great help in working out structures and determining the biosynthetic origin of terpenes.
Find the isoprene units in the following terpenoid natural products.
[VISUAL]
Model Answer
The solution displays structural drawings of the given terpenoid natural products (such as taxol derivatives, cholesterol, and pinene) with dividing lines showing how their carbon skeletons are composed of head-to-tail connected isoprene units.
Draw the repeating unit in each polymer product.
[VISUAL]
HOOC-R-COOH + H2N-R'-NH2 --(salt, heat--> Nylon-6,6
Phthalic anhydride + Glycerol --(heat--> Glyptal
Diisocyanate + Diol ⟶ Polyurethane
Model Answer
The solution shows structural drawings of the repeating units:
- Nylon-6,6: -[CO-(CH2)4-CO-NH-(CH2)6-NH]-
- Polyurethane: -[CO-NH-C6H3(CH3)-NH-CO-O-CH2-CH2-O]-
- Glyptal: Three-dimensional polyester network formed from phthalic anhydride and glycerol.
Nature also was suspected to have used basic building blocks such as HCN, NH3 and water that are observed in interstellar space to produce adenine, guanine, cytosine and uracil in the “prebiotic system” as Oro has demonstrated in 1960.
Identify the origin of each carbon and nitrogen atoms of these bases from HCN, NH3 and H2O
[VISUAL]
Model Answer
The solution shows structural formulas of adenine, guanine, cytosine, and uracil with clear annotations/labels mapping every individual carbon and nitrogen atom to its prebiotic precursor molecule (HCN, NH3, or H2O).