Question

1. Explain why DNA is the ideal genetic material. That is, explain how DNA uniquely fulfills these properties of the genetic material:

   1. Stores information securely

   2. Is replicated accurately

   3. Genetic information can be used

   4. Genetic variability occurs so that species can evolve

Answer 1

DNA - Deoxyribose nucleic acid is the genetic material in almost all living beings (Except for some viruses). DNA is present inside the nucleus in Eukaryotes as chromosomes. In prokaryotes, DNA is present as compact mass inside the cell. DNA is used as genetic material. It passes on information from one generation to another. The information of the entire body structure, proteins, function, the behavior is all stored in the DNA. Why does it qualified for ideal genetic material is an interesting question.
The primordial world had amino acids, carbohydrates, and RNA before the evolution of DNA. Yet DNA was chosen as genetic material. DNA has deoxyribose sugar, which makes it stable compared to RNA. DNA can easily double-stranded which increases the stability of the structure. The double-strand is based on complementarity which helps to secure the information and protects from random changes. The antiparallel nature of DNA allows for better replication, and maintain the polarity of genes.
DNA is replicated by semi-conservative methods, by a set of proteins. DNA is wound around histones, which makes it less accessible and more stable. Compaction of DNA into chromosome increases the complexity and capacity to store more information. DNA holds the information in the form of bases of nucleotides which makes up the genes. Genes can be easily amended or mutated to create more polymorphs which leads to better adaptability. Though genes arise frequently in nature, the DNA is very stable and does not allow random mutations to pile up, thanks to an extremely efficient DNA repair system. Yet, genes arise due to base-pair mutations. It allows for polymorphism, natural selection, and speciations.
The genes can be read by RNA polymerase which synthesizes short-lived messenger RNAs. These mRNA are then translated into proteins. If the DNA was not stable, it would have led to unpredictable protein structure and functions. Interestingly, RNA is not stable and gets degraded within a few minutes of transcription. It also helps to maintain adequate protein load in the cell.