Genes are segments of DNA located on chromosomes. A gene mutation is defined as an alteration in the sequence of nucleotides in DNA. This change can affect a single nucleotide pair or larger gene segments of a chromosome. DNA consists of a polymer of nucleotides joined together. During protein synthesis, DNA is transcribed into RNA and then translated to produce proteins. Altering nucleotide sequences most often results in nonfunctioning proteins. Mutations cause changes in the genetic code that lead to genetic variation and the potential to develop the disease. Gene mutations can be generally categorized into two types: point mutations and base-pair insertions or deletions.
The main difference is that organisms that have similar characteristics could be in the same species or have common ancestors
A cell theory.
Since cells are the basic unit of structure in all organisms and also the basic unit of reproduction.
DNA (or deoxyribonucleic acid) is the molecule that carries the genetic information in all cellular forms of life and some viruses. Source-
DNA, Genes and Chromosomes — University of Leicester
www2.le.ac.uk/projects/vgec/highereducation/topics/dna-genes-chromosomes
