Download What is the cell cycle?

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
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
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
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
Cell Reproduction
5
What is the cell cycle?
What are the stages and events?
Mitosis
G1
G0
S
G2
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
Cell Reproduction
8
…Metaphase
…Anaphase
Filaments ‘pull’ and “push’
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
Cell Reproduction
Advanced artistry is not required, but
drawings of supercoiled chromosomes
and spindle fibers must show
reasonable effort to accurately
represent these structures.
not
x
11
Why learn about the cell cycle?
• Cancer
• Biotechnology
Basal cell
carcinoma
Cell Reproduction
12
Embryonic stem cells could be
used to repair tissue and
organ damage
Must culture
and induce
differentiation
Cell Reproduction
13
Cancer often begins with cells that lose
control over cell replication
-- mutations accumulate over time
-- an evolutionary process
Some “oncology”
terminology
Benign tumor
Malignant tumor
Metastasis
Primary vs secondary tumor
Cancer
Cell Reproduction
14
Mutations altering 3 key cell properties and “set
the stage” for metastasis
 Mutations that trigger cell proliferation
 activation of “Oncogenes”
 Mutations that disable DNA error detection (and repair)
 disabling of “Tumor suppressor proteins”
 Mutations that confer immortality
15
Cell Reproduction
Tumor suppressor proteins are
‘Gatekeepers’ and ‘Caretakers’
of the cell
Stop
Go
Die
Cell Reproduction
16
When mutations to Tumor Suppressor Genes can disable
the corresponding Tumor Suppressor Proteins . . .
Cells divide
when they
shouldn’t
Cells do not die
when they
should
Cells progress
toward metastasis
Cell Reproduction
17
In some breast cancers, Epidermal Growth Factor (EGF)
receptor is mutated
Normal gene = “proto-oncogene”
Mutated gene = “oncogene”
Cell Reproduction
18
The Mitosis Waltz by Moxy Fruvous
The Mitotic Waltz
If it's ze secrets of life that you seek,
Zen srough (through) a mi-croscope you must peek!
Mendel did vonders just using his eye,
But to really see, you must magnify.
You can't help but notice ve're nossing (nothing) but
cells,
But vhere in ze cell does heredity dvell?
The Nu-cleus! That's vhere it hides.
You don't see much until it divides,
Then Chro-masomes enter new phases,
Split into two, und zat is ze basis
Of Sexual Transmission vhich olvays engrosses
Our feverish minds, but it's only Meiosis.
Reducing zee chromasomes fifty percent,
So vhen egg and sperm meet at zat blessed event,
Ze Chro-masomes form one full set.
Just two of each kind, zat's ze best best!
And that new cell begins to grow,
Multiplies into an Em-bryo.
Ze ex-plana-tion of zis growth
Is it's due to a process ve know as Mitosis!
And zat's vhat our Microscopes helped us determine,
In Germany, vhere un ze germ cells are German!
Cell Reproduction
19