Mitosis vs. Meiosis

How many Chromosomes are in each of your cells? 46 individual ones - (23 pairs) Diploid Cells (2n) A cell containing a full set of chromosomes; somatic or body cells Haploid Cells (n) A cell containing half a set of chromosomes; gametes or sex cells

Homologous Chromosomes – Paired chromosomes that have the same length and gene locations; one from mom and one from dad.

Mitosis Meiosis Occurs in body cells (diploid) Occurs in a gamete-producing cell (diploid) Undergoes 1 cell division Undergoes 2 cell divisions Forms 2 identical diploid cells Forms 4 genetically different haploid cells (because of cross over) Parent cell and daughter cells have the same number of chromosomes Gametes have half the number of chromosomes as the parent cell. Crossing over does not occur Crossing over does occur

Genetic Variation Crossing over in prophase I of meiosis also allows for greater genetic variation within a species.

Genetic Variation How the chromosomes line up in metaphase I of meiosis is a random process that means every gamete created will be genetically different from the parent cell and from each other.

Genetic Variation Genetic variation in a population is also created through random mating.

Why is genetic variation important? Partner A: I think genetic variation is important because___________. Partner B: Genetic variation is also important because _____________.

Fertilization is the process by which two haploid gametes, egg and sperm, combine to form a new diploid cell called a zygote.

Reproduction Asexual reproduction involves one parent and produces offspring that are genetically identical to each other and to the parent. Sexual reproduction involves two parents and produces offspring that are genetically unique. During sexual reproduction, two haploid gametes join in the process of fertilization to produce a diploid zygote. Meiosis is the type of cell division that produces gametes.