Download Section 7.2 – Meiosis Understanding Concepts #1

Section 7.2 – Meiosis
Understanding Concepts #1-8 (p. 207)
1. Somatic Cells – full set of chromosomes (diploid cell)
Reproductive Cells – half a set of chromosomes (haploid cell)
2. Chromosomes that are similar in size, shape and gene arrangements. (Each
one of the chromosomes you received from you father is matched with one
from your mom.)
3. During the first division, called meiosis I, the homologous chromosomes
move to opposite poles. During this division the diploid cells separate into 2
haploid cells. (called reduction division because chromosome number is
reduced by half.
The second phase (meiosis II) is marked by the division of the doublestranded chromosomes.
4.
Mitosis
One division
Two cells produced
Cells are identical to parent
Meiosis
Two divisions
Four cells produced
Cells contain half the
chromosome number of the
parent
5. Meiosis reduces the chromosome number in sex cells. Once 2 sex cells
combine the full set of chromosomes is reinstated. If meiosis did not occur,
the combination of sex cells would produce a zygote with double the
chromosome number. In each succeeding generation, chromosome number
would be doubled.
6. 39 chromosomes
7. Yes – genes that code for the same characteristic (eg. Eye colour) are
located in the same position along homologous chromosomes.
8. Genes code for the same characteristic but they may not be identical. For
example, the gene for eye colour is located on the same position on the
chromosome contributed by your mom and dad, but your dad might have
contributed a gene for blue eyes while your mom contributed a gene for
brown eyes.