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Chaper 4 Note-Taking Handout
Cell Reproduction: Mitosis and Meiosis
Section 1: Cell Division and Mitosis
A. Cell division – increases the number of cells and causes many-celled ________________ to
grow.
B. The Cell Cycle – series of events that takes place from one _________________ to the next.
1. Cells have periods of formation, growth and development, and death called
__________________.
2. Interphase – most of the life of any eukaryotic cell, or a cell with a nucleus, is spent in a
period of ___________________ and ___________________.
a. During interphase, a cell duplicates its ___________________ and prepares for cell
division.
b. After interphase, the nucleus divides, and then the __________________ separates to
form two cells.
C. Mitosis – process in which the nucleus divides to form two identical __________________.
1. Chromosome – structure in the nucleus that contains _________________ material.
You get half your chromosomes from your mom and half from your dad!
2. Prophase
a. Nucleolus and _______________________ disintegrate.
b. ___________________ move to opposite ends of the cell.
c. ____________________________ begin to stretch across the cell.
3. Metaphase – pairs of _______________________ line up across the center of the cell.
4. Anaphase
a. Each _____________________ divides.
b. Each pair of chromatids ________________________ and moves to opposite ends
of the cell.
5. _____________________ - spindle fibers and chromosomes disappear, and a new
nucleus forms.
D. Division of the Cytoplasm – for most cells, the ______________________ separates after
the nucleus divides.
1. In ____________________ cells, the cell membrane pinches in the middle and the
cytoplasm divides.
2. In _____________________ cells, a cell plate forms and divides the cell in half.
E. Results of mitosis
1. Each cell in your body, except sex cells, has a nucleus with ________ chromosomes.
2. Mitosis allows growth and _______________ worn out or damaged cells.
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F. _______________________ - a new organism is produced from one parent organism.
1. An organism with no nuclues divides into two identical organisms by ______________.
2. _______________ - a small, exact copy of the adult grows from the body of the parent.
3. In _______________________, a whole new organism grows from each piece of the
parent.
Section 2: Sexual Reproduction and Meiosis
A. _____________________ reproduction – two sex cells, usually an egg and a sperm, come
together.
1. Fertilization – the joining of an ____________ and a __________, generally from two
different organisms of the same species.
a. Sperm are formed in the ______________ reproductive organs.
b. Eggs are formed in the ______________ reproductive organs.
c. A cell that forms from fertilization is a ______________________.
2. Following fertilization, _________________ begins and a new organism develops.
3. Human body cells are ________________, because they have 23 pairs of similar
chromosomes.
4. Human sex cells are ______________, because they have 23 single chromosomes.
B. __________________ - a process that produces haploid sex cells and ensures that offspring
have the same _____________________ number as its parent.
1. Meiosis ________________ the number of chromosomes in the body cells in half to
make sex cells. So that when the sex cells combine there is the correct number!
2. One body cell ends up as _____________ sex cells.
3. Each sex cell has ___________ the number of chromosomes as a body cell.
4. Human body cells have ___________ chromosomes, sex cells have _____________.
5. Any organisms sex cells have ____________ the number of chromosomes that the
body cell has. A bee might have 10 chromosomes, its sex cells would have ________.
6. In Meiosis I, the nucleus divides and produces two new cells with one duplicated
___________ each.
7. In meiosis II, the nuclei divide and the chromatids separate, producing _________ cells
with half the number of chromosomes of the original nucleus.