sexual reproduction is performed through gametes which means that each cell has half the number of chromosomes (for humans that's 23) . also called haploids, when the two cells combine the chromosmes cross creating a whole set of chromosomes. (46 in humans)
asexual reproduction is done through meiosis through somatic cells that already have two sets of chromosomes. (46 in humans) they duplicate the chromosomes and then spilt to create a perfect duplicate. the cells can also be know as diploids.