Unlock your academic potential with my notes on Cell Biology, tailored specifically for students pursuing Biomedical Science, Biochemistry, Biology, Biophysics, Genetics, Biomedical Engineering, Biotechnology, Bioengineering, Pharmacology, Medicine, Nursing and so on. These notes are perfect for an...
Slides and links to presentations available on Moodle.
Image on slide: Cell regulation and mitosis
o Histone – Red
o Tubules - green
Aneuploidy- unexpected or wrong number of cells
The cell division cycle – the division of its parental cell until the moment it too divides into
two daughter cells.
Yeast: Multiply every 2-3 hours
Human cell in culture: 24 hours (these are more organised and complex due to replicating all
the DNA).
Common strategy from yeast to man: DNA replication phase (S phase) and Cell
division (M phase)
Replicate (S phase) - is the process by which a double-stranded DNA molecule is copied to
produce two identical DNA molecules.
Cell Division (M phase) - during mitosis, a cell duplicates all of its contents, including its
chromosomes, and splits to form two identical daughter cells. These phases must be carried
out accurately in the correct order to avoid mutations.
1
, The cell division cycle consists of 4 Phases:
1) S Phase – DNA replication
2) M phase – Cell division, the cell splits into two identical daughter cells.
3) G1 – the cell grows and makes a new set of organelles and proteins for the daughter
cells.
4) G2 – cell growth continues in preparation of mitosis.
These growth phases (G1 and G2) are points at where the cell makes sure it is okay, i.e. Are
there any mutations? Gap phases are essential and create control points during cell division.
G1/S control: Am I big enough? What do the neighbors think?
G2/m control: How’s my DNA? Is it all replicated correctly?
Why is this important?
All cells undergo cell division, from bacteria to humans. When things go wrong in cell
division, this can lead to cells becoming out of control and over produce the number of cells
(these are cancer cells).
In 2001 Paul Nurse, Tim hunt and Lee Hartwell won a Nobel prize for identifying the key
regulators of the cell cycle. During this they used yeast, which has similar components to
DNA.
History of classical experiments in the cell cycle
Classic experiment:
Cell fusion: Roa & Johnson (1970) took a cell in S-phase and fused it to cell in G1 phase.
They found the S phase drove the G1 cell into S phase. This was replicated using S phase
and G2 phase which did not have the priming factor. Fused G1 cell to G2 cell but nothing
happened. G2 and the Mitotic cell drove G2 cell into mitosis.
Experiment 2: Masui (1979)
Maturation of xenopus oocytes – they used an Oocyte in its m phase and took some of the
cytoplasm and injected it into oocyte in G2, which drove it into myosis Phase. This was
repeated using progesterone.
Maturation promotion factor = MPF
Oscillations of MPF (Image of graph to show process)
They took the cytoplasm of each stage
and determined whether it could drive
each cell into mitosis. MPF is activated at
2
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller morgan_helene. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £10.49. You're not tied to anything after your purchase.
