So how do microbes
cause B cells and T cells
to grow and divide?
Each cell has a receptor on its
cell surface that recognizes a
specific part of a microbe.
That receptor triggers a
Signal transduction pathway.
This triggers gene expression
(transcription) that…
…leads to protein synthesis
(translation) that…
…allows the cell to grow
(duplicate all its proteins that
help to duplicate all its organelles)
and divide (mitosis).
On to the
Cell cycle!
Watch this movie to
link transcription
and translation to
the cell cycle:
http://highered.mcgra
whill.com/sites/007352
543x/student_view0/c
hapter9/stimulation_o
f_cell_replication.html
Cell Reproduction
• Check this out!!
• Breast cancer cells dividing:
• http://www.youtube.com/watch?v=Hm03
rCUODqg&NR=1&feature=fvwp
The Cell Cycle
– Eukaryotic cells that grow and divide undergo an orderly
sequence of events called the cell cycle.
– The cell cycle consists of two distinct phases:
• Interphase
– Cell growth
– Sub-phases:
» G1
» S phase
» G2
• Mitotic phase
– Cell division
http://highered.mcgrawhill.com/sites/007352543x/student_view0/chapter9/how_t
he_cell_cycle_works.html
From One gene to 25,000 genes
– OK, we’ve talked about
how to transcribe and
translate one gene found
on the DNA in our nuclei
into a functioning protein.
But we have more than
just one gene….
– Almost all of the genes of
a eukaryotic cell
• Are located on
chromosomes in the cell
nucleus.
Transcription and Translation
occur all throughout Interphase:
when the cell is growing
and duplicating all of its
cell structures and organelles!!
Eukaryotic Chromosomes
– Each eukaryotic
chromosome
contains one very
long DNA molecule,
• Typically bearing
thousands of genes.
– The number of
chromosomes in a
eukaryotic cell
• Depends on the
species.
– Detailed representations of DNA
• Notice that the bases pair in a complementary
fashion.
DNA Replication
– When a cell or
whole organism
reproduces, a
complete set of
genetic
instructions
must pass from
one generation
to the next.
– This happens
during S phase
Figure 10.8
The Cell Cycle
– Eukaryotic cells that grow and divide undergo an orderly sequence of
events called the cell cycle.
– The cell cycle consists of two distinct phases:
• Interphase
– Cell growth
– Sub-phases:
» G1
» S phase
» G2
• Mitotic phase
– Cell division
Mitosis and Cytokinesis
– Mitosis
• Is the division of the chromosomes.
• Is preceded by interphase.
From movie folder play:
- AnimalMitosis_SV.mpg
– Chromosomes
• Are made of chromatin, a combination of DNA
and protein molecules.
• Are not visible in a cell until cell division occurs.
– The DNA in a
cell is packed
into an
elaborate,
multilevel
system of
coiling and
folding.
– Before a cell
divides, it
duplicates all of
its chromosomes,
resulting in two
copies called
sister chromatids.
– When the cell
divides, the sister
chromatids
separate from
each other.
G1 phase
S phase
G2 phase
M phase
Figure 8.8.1
– Mitosis consists of four distinct phases:
•
•
•
•
Prophase
Metaphase
Anaphase
Telophase
Figure 8.8.2
Mitosis recap:
http://facweb.northseattle.edu/csheri
dan/Biology160_Fa12/movies/mitosi
s_movies/08_06bMitosisOverview_
A.html
– Cytokinesis
• Typically occurs
during
telophase.
• Is the division of
the cytoplasm.
• Is different in
plant and animal
cells.
Figure 8.9b
http://www.youtube.com/watch?v=SlgV_zoHQxE&p=AC919FD768804
41F&playnext=1&index=39
Cancer Cells: Growing Out of
Control
– Normal plant and animal cells have a cell
cycle control system.
– Cancer is a disease of the cell cycle.
– Cancer cells do not respond normally to
the cell cycle control system.
http://www.youtube.com/watch?v=Hm03rCUO
Dqg&NR=1&feature=fvwp
– Cancer cells can form tumors,
• Abnormally growing masses of body cells.
– If a tumor is malignant,
• It can spread to other parts of the body.
Cancer Treatment
– Cancer treatment can involve
• Radiation therapy, which damages DNA and disrupts
cell division.
• Chemotherapy, which uses drugs that disrupt cell
division.
• Turn and talk: How would damaging the
DNA of a cell disrupt cell division?
– Cancer
cells are
often grown
in culture
for study.
Cancer Prevention and
Survival
– Cancer prevention includes changes in lifestyle:
•
•
•
•
•
•
Not smoking
Exercising adequately
Avoiding exposure to the sun
Eating a high-fiber, low-fat diet
Visiting the doctor regularly
Performing regular self-examinations