Download Cell Cycle Notes

Onion Root Tip & Cell Cycle Lab
How many stages of cell division
do you see in this image?
Cell Cycle Notes
What are the key roles of cell division?
• Cell division functions in:
– Reproduction for some organisms
– Growth of an organism from a fertilized egg
– Repair of cells that die from normal wear and
tear or accidents
• Cell division distributes identical sets of
chromosomes to daughter cells
Cell Cycle Notes
• DNA molecules are packaged into
chromosomes .
– Human somatic cells (body cells)
have 46 chromosomes
– Human gametes (sperm or eggs)
have 23 chromosomes
• Chromosomes are made of a
chromatin.
material called__________.
• When chromatin tightly condenses
in preparation for cell division, it is
referred to as a chromosome.
Cell Cycle Notes
• Chromatin is composed of DNA and
proteins. Chromatin is the “relaxed” or
“unwound” form of our genetic material that
is present during most of a cell’s life.
• DNA is supercoiled around proteins called
histones.
• Together the DNA and histone proteins form
bead-like structures called
nucleosomes
• DNA + 8 histone proteins = a nucleosome
Mitosis Notes
• The chromosome is
S in
duplicated during ___
_____________.
interphase
• Each duplicated
chromosome consists
of two sister
chromatids
.
• These are connected by a
centromere .
What is the difference between
interphase, mitosis, and cytokinesis?
Mitosis (M Phase)
The M Phase consists of:
• Mitosis and Cytokinesis
Four Stages of Mitosis:
Prophase
Metaphase
Anaphase
Telophase
RE-identify the stages of Mitosis