Unit 3 – Part 2:
Mitosis and Meiosis
Essential Concepts and Skills
1. Understand the phases
This process is ONE division……
Reading
of Mitosis (cell cycle):
Pg.92-97
a) Interphase – Cell grows and develops until it reaches maximum capacity.
Chromosomes replicate so that each consists of two identical strands
known as chromatids. The strands are joined together by a centromere.
b) Mitosis – a process of four phases in which the nucleus of eukaryotic cell
divides into two nuclei each containing a complete and identical set of the
cell’s chromosomes.
a. prophase – chromosomes coil and become shorter and thicker. The
nuclear membrane dissolves. Centrioles move toward opposite sides
of cell. As the centrioles move apart fibers form in between them.
The centromere’s of the chromosomes attach to the fibers.
b. metaphase - each chromosome, attached to spindle fibers, lines up in
the center of the cell ( along the cell’s equator).
c. anaphase – The chromatids separate and are pulled to opposite sides
of the cell by the fibers attached to the centrioles.
d. telophase – each side of cell now has a complete set of
chromosomes. The nuclear membrane reforms around each set of
chromosomes, the chromosomes uncoil, and the spindle fibers
disappear. This is the final stage phase of mitosis
c) Cytokinesis – occurs after mitosis
a. in animal cells, the cells actually pinch in two
b. in plant cells, a new cell wall is built through the middle of the cell
*Two new identical daughter cells are formed from the cell division
2. Understand the outcome of Meiosis
1. This process has two divisions. Ending with…..
a. Produces 4 sex cells (gametes).
b. Each egg is different (this is why you and siblings are different)
c. Male gamete called sperm.
d. Female gamete called egg.
e. Takes place in reproductive organs. (ovaries & testes)
Pg.
114-118
Mitosis
Occurs during cell division that
produces body cells.
Produces two identical diploid cells.
Each cell contains copies of all the
chromosomes.
Mercer Middle
Loudoun County Public Schools
Aldie, VA
Meiosis
Occurs during cell division that
produces gametes.
Produces four haploid gametes.
Each gamete contains copies of
one of each kind of chromosome.
Chromatid
Centromere
-Each gamete has ½ the number of chromosomes. (Haploid)
ASSESMENTS:
Mercer Middle
Loudoun County Public Schools
Aldie, VA