DR AMR ALAA
89) Which of following could happen from a nondisjunction in homologous
chromosomes?
A. All cells will have an extra chromosome.
B. Half of the cells will have an extra chromosome.
C. All the cells will have one less chromosome.
D. One-quarter will have an extra chromosome.

When nondisjunction occurs in homologous chromosomes during meiosis, it’s like a bit of mischief at the cell party! Instead of splitting evenly, one gamete may end up with both chromosomes while the other gets none. This means that half of the resulting gametes can have an extra chromosome (the ones with the “party crasher”), while the other half might lack it completely.

So if we break it down in simpler terms: imagine a two-slice pizza that’s supposed to be divided evenly—one person grabs two slices (the extra chromosome) while the other leaves empty-handed. This lovely mishap leads often to conditions like Down syndrome, where an extra copy of chromosome 21 is present, impacting development!