Cellular Reproduction
Chapter 6:
pp. 116-137
Definitions Related to Cell
Division
 Gene-a segment of DNA that codes for a
protein or RNA molecule
 Chromatid- one pair of strands of DNA that
make up a chromosome
 Centromere-
Chromosomes-
DNA tightly coiled
around proteins
Humans have 46
Chromosomes affect Development
 Homologous Chromosomes
Similar in shape size and genetic content
 Diploid

2 sets of chromosomes
 Haploid

One set of chromosomes
 Zygote

Fertilized egg cell, the first cell
Chromosomes affect Development
 Autosomes

Chromosomes that do not determine sex
 Sex Chromosomes

Contain genes that determine male or female
 Karyotype

A picture of the chromosomes in a dividing cell
that shows the chromosomes arranged by size.
In your book
The Cell Cycle (Fig 6-6)
Interphase:
90% of time
1. First Growth (G1)

Cell grows rapidly
2. Synthesis Phase (S)

Cell’s DNA copied
3. Second Growth (G2)

Prepare for Mitosis
Cell Division- 3 types
1. Binary Fissionasexual
reproduction that
produces identical
offspring
Cell Division
2. Mitosis – (Fig 6-9)
In your book
 Nucleus of cell
divides
Skin Cells
Cells must divide because Surface
Area to Volume ratios get too small
Cellular
Reproduction
Link!Mitosis
animation
Prophase
 Chromosomes coil up
and become visible.
 The nuclear envelope
dissolves and a spindle
forms.
Metaphase
 Chromosomes move to
the middle of the cell
and line up along the
equator.
 Spindle fibers link the
chromatids of each
chromosome to
opposite poles.
Anaphase
•Centromeres divide
•Chromatids (now
called chromosomes)
move toward opposite
poles
Telophase
 A nuclear envelope
forms around the
chromosomes at each
pole
 Chromosomes uncoil
 LAST step in mitosis
In your book
Cytokinesis (Fig 6-10)
•Cytoplasm is divided
in half.
•Cell membrane
encloses each cell