Question

What properties must the genetic material posses md how does dna fulfill these properties

Answer 1

Genetic material should possess the following characteristics:

1) Genetic material must be stable and ubiquitously present in all cells.

2) It should be able to make copies of itself, so that it can be passed to subsequent generation.

3) It should contain all relevant information required for the biological functioning of the cell. Further, genetic material should be able to express this information too. Genetic material should have a code that stores all information.

4) Genetic material should also be amenable to slow changes over time, thereby leading to diversity amongst organisms. The slow changes must also be stable and passed on or inherited to subsequent generations.

5) Despite the genetic material being same in all cells, its expression pattern should vary among different cell types.

DNA is commonly the genetic material in many organisms. Its properties that make it an ideal genetic material are:

1) DNA is stable over time. It can survive outside the cell as well. DNA can remain in the environment for a very long time. This property of DNA is used for dating of fossils.

2) DNA is present in all cells of the organism. Somatic cells are diploid having twice the amount of DNA as haploid germ cells.

3) DNA undergoes replication in the S phase (interphase) of the cell cycle. During cell division, replicated DNA is equally distributed to daughter cell via mitosis. Thus, daughter cells will also have DNA as the genetic material.

4) DNA can be mutated, due to changes in the sequences of nitrogenous bases. Thus, genes are mutated due to differences in nucleotide sequences of the DNA. Mutations can occur due to absorption of ultra violet rays. Recombination in DNA also allows for genetic diversity.

5) The mutations are heritable and will be passed to subsequent generation when DNA is replicated. DNA replication uses existing strands as templates to copy the information.

6) DNA is transcribed to mRNA, which has triplet codons, coding for amino acids. Thus, DNA stores genetic information in a cell via a triplet code.

7) DNA is transcribed to mRNA and translated to proteins. Different alleles of the gene will lead to differential expression of proteins. This will lead to different cell types.

8) DNA repair process are able to repair damage to DNA. Thus, most mutations can be repaired vis these processes and reduce harm to the cell.