Fundamentals of Molecular Biology. Part 1: Molecular Cell Biology - A. N. Ogurtsov 2011
Nucleic Acids and Proteins
Combinatorial Nature of Molecular Diversity
Summarizing this Brief Overview of the Chemical Structure of living organisms, we can conclude that the colossal diversity of life observed in nature is determined not by atomic, but by molecular diversity, which is primarily combinatorial in nature (Figure 113).
Class="center">
Figure 113 - Formation of Biopolymers and Biomembranes
Indeed, the thousands of diverse, large, and complex molecules that make up Living organisms are constructed from just 30 basic, simple organic building blocks:
✵ twenty L-Amino Acids,
✵ five nitrogenous bases (uracil, thymine, cytosine, adenine, and guanine),
✵ two sugars (D-glucose and D-ribose),
✵ one nitrogen-containing alcohol (Choline),
✵ one 16-carbon saturated fatty acid (palmitic acid),
✵ one 3-carbon alcohol (glycerol).
Moreover, in the case of irregular polymers (Proteins and Nucleic Acids), their diversity is determined by the varied sequence of several types of monomers, whereas in regular polymers (Polysaccharides), it is determined by The Diversity of chemical bonds between identical monomers (Figure 113).
The vast diversity of biological molecules predetermines an even greater variety of interactions among them. This diversity tends to grow indefinitely due to The formation of novel objects resulting from the interaction of pre-existing ones. Consequently, the combinatorial principle underlying The structure of major biological substances appears to be absolutely essential for the evolution of living organisms, as this is arguably the only way new material for natural Selection can efficiently arise.
1. NUCLEOTIDES are monomers of which polymers?
2. What are the monomers that form nucleic acids called?
3. What are the Similarities and differences between nucleotides and nucleosides?
4. List the pyrimidine nucleic acid bases.
5. List the purine nucleic acid bases.
6. List the Watson-Crick Base Pairs.
7. List the structural principles of DNA.
8. What forms of DNA Helical structures do you know? Which of them is the primary one? How do the B- and Z-forms of DNA helices differ?
9. List the Functions of DNA.
10. What are the differences between DNA and RNA?
11. List the types of RNA.
12. List the levels of DNA packaging into a chromosome.
13. What are the monomers that make up proteins called?
14. What are the Main Components of an amino acid molecule?
15. What is the name of the only imino acid involved in METABOLISM/35.html">Protein Biosynthesis?
16. How are amino acids classified based on the polarity of their side chains?
17. List the nonpolar amino acids.
18. List the aliphatic amino acids.
19. List the aromatic nonpolar amino acids.
20. List the polar uncharged amino acids.
21. WHAT IS A zwitterion? Write down the zwitterion structure of an amino acid.
22. List the hydroxy amino acids.
23. List the charged amino acids.
24. List the negatively charged amino acids.
25. List the positively charged amino acids.
26. Which proteins are referred to as Polypeptides?
27. Write the peptide bond.
28. Which Amino acids are classified as non-essential?
29. List the non-Essential Amino Acids.
30. Which amino acids are classified as essential?
31. List the essential amino acids.
32. Which amino acid is considered conditionally essential and why?
33. What is the Introduction/19.html">Primary Structure of a protein?
34. What types of bonds stabilize the primary structure of a protein?
35. What is the Secondary structure of a protein?
36. What interactions stabilize the secondary structure of a protein?
37. What is the Tertiary Structure of a protein?
38. What interactions ensure the Stability of the tertiary structure of a protein?
39. How are Disulfide Bonds formed?
40. What is meant by The quaternary structure of a protein?
41. What interactions ensure the stability of the Quaternary Structure of a protein?
42. What are the similarities and differences between The concepts of protein and polypeptide?
43. List the main Functions of Proteins.
Last update: 12/08/2026
Editorial and Educational Adaptation: This material has been compiled based on the primary/original source text. The project team performed an editorial review, corrected technical inaccuracies, structured sections, and adapted the content for an educational format.
What was processed:
- elimination of formatting defects (OCR errors, structural breaks, corrupted characters);
- editorial organization of content;
- standardization of terminology in accordance with academic sources;
- verification of factual statements against the original source text.
All mentions of the author, publication year, and origin of the primary text have been preserved in accordance with the source.