Name: ______________________________ Section:__________________ Date: ___________

Sexual Reproduction: Meiosis (25pts)Instructions: Fill in the blanks with the correct terms.

Sexual reproduction is advantageous. It combines different parental alleles to produce a genetically (1) _____________ offspring. The combining of genetically determined traits can lead to (2) _________________________, which is beneficial to a species as a whole. The somatic cells of the body contain (3) _________________________, which code for the same genes, but have different alleles. They are matched in length, centromere position, and (4) ___________________. Meiosis produces haploid (5) _____________, which are (6) _________ in males and (7) _________ in females. The union of the two is called (8) ________________, and forms a diploid (9) _______________.

Meiosis has two cell divisions, called meiosis I and meiosis II. In meiosis I, (10) ____________________ separate, forming haploid cells. In meiosis II, (11) _____________________ separate. Like mitosis, meiosis is preceded by (12) _____________, in which the DNA is duplicated.

Prophase I is one of my most important stages of meiosis I. In prophase I, homologues up in a process known as (13) ________________, and forms the resulting structure, called (14) ___________. The homologues are held together by the (15) ____________________, which is composed primarily of cohesin and protein filaments. Crossing over also occurs in prophase I. The sites of crossing over are called (16) _________________.

In metaphase I, the tetrads align along the (17) _________________. The orientation of the paternal and maternal homologues towards the poles are (18) ______________, which increases genetic variability. This concept is called (19) ____________________________, and the number of possible chromosomal combinations is (20) ____________.

At the end of meiosis, (21) ______________ haploid cells are produced from one parent cell. Mitosis and meiosis differ in some ways. There are (22) ______ cell divisions in meiosis, as opposed to 1 in meiosis. Mitosis is often used for growth and repair, while meiosis is used for (23) _________________, the production of sperm, and (24) ___________________, the production of eggs. When sperm and egg fuse, the genetic variability further increases, and the number of possible chromosome combinations will be (25) ___________.