During meiosis-I, the exchange of genetic segments between the homologous chromosomes occurs. This is called crossing over. The recombinant chromatids formed during crossing over have new combinations of alleles that were otherwise not present in the parental chromatids. Similarly, the random assortment of alleles of different genes towards the opposite poles of the cell during anaphase-I also creates new gene combinations. These events of gene shuffling during meiosis recombine the genetic material and add genetic variations in the progeny.
When genetic material undergoes any random change in its sequence, the corresponding mRNA sequence is also altered. This results in the formation of faulty, nonfunctional, less functional or no protein from the mutated mRNA. Therefore, the sudden changes in DNA called mutations also add variations.
Two cells in the same organism differ only in the number of chloroplasts they contain. The first cell has multiple chloroplasts, and the second cell has very few. What would most likely characterize these cells? The second cell would not be able to produce as much food because it could not capture sunlight
The immune system acts as a defense system of the body. It fights against bacteria, viruses and any other disease causing pathogens. Some chemicals can weaken the immune system and make them vulnerable.
