AP BIOLOGY

HEREDITY

NONDISJUNCTION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
The failure of homologous chromosomes to separate properly during meiosis is called ____
A
fertilization
B
cell cycle
C
nondisjunction
D
cytokinesis
Explanation: 

Detailed explanation-1: -Nondisjunction is the failure of the chromosomes to separate, which produces daughter cells with abnormal numbers of chromosomes. [

Detailed explanation-2: -Nondisjunction means that a pair of homologous chromosomes has failed to separate or segregate at anaphase so that both chromosomes of the pair pass to the same daughter cell. This probably occurs most commonly in meiosis, but it may occur in mitosis to produce a mosaic individual.

Detailed explanation-3: -Aneuploidy is caused by nondisjunction, which occurs when pairs of homologous chromosomes or sister chromatids fail to separate during meiosis. The loss of a single chromosome from a diploid genome is called monosomy (2n-1), while the gain of one chromosome is called trisomy (2n+1).

Detailed explanation-4: -Nondisjunction, in which chromosomes fail to separate equally, can occur in meiosis I (first row), meiosis II (second row), and mitosis (third row). These unequal separations can produce daughter cells with unexpected chromosome numbers, called aneuploids.

Detailed explanation-5: -Nondisjunction is the failure of homologous chromosomes to disjoin correctly during meiosis. This results in the production of gametes containing a greater or lesser chromosomal amount than normal ones. Consequently the individual may develop a trisomal or monosomal syndrome.

There is 1 question to complete.