Chapter 9: Meiosis

What is meiosis?

Meiosis is cell division that produces gametes, which are reproductive cells containing half the number of chromosomes found in somatic cells.

What is a gamete?

A gamete is a reproductive cell (egg or sperm) that is haploid, meaning it contains one set of chromosomes.

What occurs during fertilization?

During fertilization, gametes fuse to form a new cell called a zygote, which is diploid and contains two complete copies of each chromosome.

How does meiosis support genetic diversity?

Meiosis promotes genetic diversity through independent assortment, crossing over, and random fertilization.

What happens during prophase I of meiosis?

During prophase I, homologous chromosomes pair up and exchange segments through a process called crossing over.

What characterizes metaphase I of meiosis?

In metaphase I, paired homologous chromosomes align randomly along a central plane, which contributes to genetic variation.

What is the outcome of meiosis I?

At the end of meiosis I, one diploid cell divides to become two haploid cells.

What is unique about meiosis II compared to mitosis?

Meiosis II is similar to mitosis but occurs in haploid cells, and the sister chromatids are nonidentical due to crossing over.

What is independent assortment?

Independent assortment is the random orientation of homologous chromosomes during metaphase I, leading to different combinations of parental chromosomes.

What results from improper separation during meiosis?

If homologous chromosomes or sister chromatids fail to separate during meiosis, it can lead to aneuploidy, which is an incorrect number of chromosomes in the daughter cells.