One cell with extra homologous chromosomes and one cell missing a homologous chromosome. Which describes the cells at the end of meiosis I when nondisjunction occurs in meiosis II? The homologous pairs are in separate cells. The cells are haploid.
What is the result of a nondisjunction during meiosis II?
Nondisjunction only results in gametes with n+1 or n–1 chromosomes. Nondisjunction occurring during meiosis II results in 50 percent normal gametes.
What describes the cells at the end of meiosis 1 when nondisjunction occurs during meiosis 2?
Nondisjunction Produces Abnormal Gametes
If nondisjunction occurs during anaphase I of meiosis I, this means that at least one pair of homologous chromosomes did not separate. The end result is two cells that have an extra copy of one chromosome and two cells that are missing that chromosome.
What is the end result when a nondisjunction occurs during meiosis I?
Nondisjunction in meiosis I occurs when the tetrads fail to separate during anaphase I. At the end of meiosis I, there will be 2 haploid daughter cells, one with n+1 and the other with n-1.
What is the difference between meiosis 1 and meiosis 2 quizlet?
Meiosis I is a reduction division where only one member of a homologous pair enters each daughter cell which becomes halploid. Meiosis II only splits up sister chromatids.
What is the result of nondisjunction?
Nondisjunction in meiosis can result in pregnancy loss or birth of a child with an extra chromosome in all cells, whereas nondisjunction in mitosis will result in mosaicism with two or more cell lines. Aneuploidy may also result from anaphase lag.
Why is Nondisjunction more common in females?
We speculated that for young women then, the most frequent risk factor for MI nondisjunction is the presence of a telomeric exchange. As a woman ages, her meiotic machinery is exposed to an accumulation of age-related insults, becoming less efficient/more error-prone.
What is nondisjunction example?
Nondisjunction: Failure of paired chromosomes to separate (to disjoin) during cell division, so that both chromosomes go to one daughter cell and none go to the other. Nondisjunction causes errors in chromosome number, such as trisomy 21 (Down syndrome) and monosomy X (Turner syndrome).
How does nondisjunction appear in meiosis I and II?
Nondisjunction occurs when homologous chromosomes (meiosis I) or sister chromatids (meiosis II) fail to separate during meiosis. An individual with the appropriate number of chromosomes for their species is called euploid; in humans, euploidy corresponds to 22 pairs of autosomes and one pair of sex chromosomes.
Can nondisjunction occur in mitosis?
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.