Long strands of DNA wrapped around proteins

One molecule of DNA that has coiled up tightly

• Two molecules of DNA but still considered to be 1 chromosome
• Duplicated during the S phase of cell cycle
• Looks like an X

 an enzyme that keeps chromosomes from getting tangled up

• One of two copies of each chromosome
• Only on a duplicated chromosome

• Two identical copies of the chromosome
• Only present in a duplicated chromosome

a protein disk that joins two chromatids together

• located on the centromere
• where spindle fibers attach

Human cells have _____ different chromosomes or pairs of chromosomes

A pair of chromosomes that are similar in shape, size and have similar genetic information

Human cells have a total of _____ chromosomes

• 2n
• two of each type of chromosome
• Example - human 46

• n
• one of each type of chromosome
• Example - human 23

• Sequence of growth and division of a cell
• Consists of 5 phases: G1, S, G2, M, C

G1

S

G2

M

• First phase of the cell cycle
• Cell grows
• Makes organelles and proteins

• Second phase of the cell cycle
• "Synthesis"
• DNA replicates

• Third phase of the cell cycle
• "Gap"
• Produces proteins needed for mitosis

• Fourth phase of the cell cycle
• Mitosis - somatic cells
• Meiosis - gametes

• Final phase of cell cycle
• cytokinesis occurs

Cytoplasm divides separating into 2 identical daughter cells

• Consists of G1, S, G2
• Cell spends most of its life

Type of nuclear division that divides into 2 daughter cells that are identical

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

• Chromatin coils up into chromosomes
• Centrioles form and move toward opposite poles
• Spindle fibers form
• Nuclear envelope breaks down

• Spindle fibers attach to kinetochore
• Chromosomes line up in a single file straight line

• Sister chromatids separate and move toward opposite poles
• Microtubules shorten and pull chromosomes to the poles
• Once chromatids are separate, they are called chromosomes

• Chromosomes uncoil
• Centrioles break down
• Spindle fibers break down
• Nuclear envelope forms
• Once two nuclei form telophase is over

No cell wall so cytoplasm pinches in and creates a cleavage furrow that will eventually split into two daughter cells

An indentation in plasma membrane of an animal cell during cytokinesis

Have cell wall so it cannot pinch in.  Cell plate forms down center of cell dividing into two daughter cells

• Noncancerous
• Grow slowly
• Stay in their home tissue
• Pose no threat to body

• Cancerous
• Disrupt surrounding tissues
• Metastasis

• Cells can break loose from home tissues and invade other tissues