Cell Division
Cell cycle and Mitosis:
Chapter 10
Not responsible for:
Figure 10.3 & related text on proteins that control
chromosome separation and septum formation
10.7 Control of the cell cycle. This section covers more
of the molecular details than you will be responsible for;
however, we will cover the concept of cell cycle
checkpoints, oncogenes and tumor suppressor genes as
related to cancer
Question
Cell Reproduction
1
Why is it important to
understand the processes
of cell replication?
Diversity & evolution
Cancer
Birth defects
Basal cell carcinoma
Reproductive biotechnology
eukaryotic
prokaryotic
Question
Cell Reproduction
2
What are the characteristics of cell
division in Prokaryotes?
Simpler structure
No nucleus
Single chromosome
Binary fission
Cell Reproduction
3
Chromosome structure in
eukaryotes
Structure of chromosomes
… in nondividing cells
… in dividing cells
Supercoiling
Question
Cell Reproduction
4
What are homologous chromosomes?
Homologous Chromosomes:
-- one derived from each parent
-- possess same genes, although genetic
information in gene may be different
= “alleles”
How many homologous chromosomes
do different organisms possess?
humans: 2N = 46
N= haploid # of chromosomes
goldfish: 2N=94
crayfish: 2N = 200
Autosomes vs sex chromosomes
Question
Cell Reproduction
5
What is the cell cycle?
What are the stages and events?
Mitosis
G1
G0
S
G2
Question
Cell Reproduction
6
What are the steps of mitosis?
When does mitosis occur?
What are the stages of mitosis?
prophase
prometaphase
metaphase
anaphase
telophase
Cytokinesis
Animal cell mitosis
Cell Reproduction
7
McGraw-Hill mitosis
What happens during
prophase?
Chromosome condensation
Spindle apparatus
Centrosomes
kinetochore
What happens during
prometaphase?
Nuclear membrane
Spindle attachment
Kinetochores
Question
Cell Reproduction
8
…Metaphase
…Anaphase
Filaments ‘pull’ and “push’
Question
Cell Reproduction
9
Telophase and cytokinesis
What happens during telophase?
What causes cytokinesis to occur?
Does cell division in plants
and animals differ?
Plant cell mitosis
Cell Reproduction
10
Homework assignment:
5 points: due next class
For a cell where 2N=6, draw a series of diagrams showing the chromosomes
moving through the stages of mitosis.
In one of the diagrams clearly label:
-- a pair of homologous chromosomes
-- two sister chromatids
-- spindle fibers
-- centrosomes and
-- position of a kinetochore
Label all stages (prophase, prometaphase,
metaphase, anaphase and telophase)
Make diagrams large, clear and neat
Advanced artistry is not required, but
drawings of supercoiled chromosomes
and spindle fibers must show
reasonable effort to accurately
represent these structures.
not
x
Question
Cell Reproduction
11
What is the difference between
a ‘tumor’ and ‘cancer’?
Benign vs malignant tumors
Metatasis
Primary vs secondary tumors
The angiogenesis problem
Why are tumors and
cancer so harmful?
Angiogenesis and Metastasis
Cell Reproduction
12
What causes a tumor to grow?
Loss of control of cell division
What are Protooncogenes?
-- proteins they code for act as
molecular ‘switches’ for cell division
Oncogene = mutated protooncogene
-- ‘switch’ is locked in
the ‘on’ condition
What are Tumor Suppressor Genes?
-- proteins they code for stop
abnormal cells from reproducing
-- damaged DNA
-- cell cycle ‘checkpoints’
Mutated tumor suppressor gene
-- “Stop” signals do not work
Other mutations cause tumorous
cells to spread as a cancer
= “Metastasis”
Cell Reproduction
13
Stem cells and cloning
What are stem cells?
Embyonic vs somatic
How is cloning performed?
Mitotic Waltz
Cell Reproduction
14