10-1 Cell Growth
Complete Guided Reading Workbook 10-1
By the end of today you will be able to:
Explain the problems that growth causes for
Describe how cell division solves the
problems of cell growth.
Name and describe the main events of the
Let’s do some math!!!!
surface area of S.A. = 4 (pi) r 2
volume of each
sphere. S.A. = ________
V = __________
Then, calculate the S.A. = ___50cm2__
Ratio SA:V = ________
surface area to V = __33cm3____
volume ratio. Round #’s
up or down to make it easier. Ratio SA:V = 50:33_or 1.51:1
Radius 1cm Radius 2cm Radius 3cm
S.A. = _____
S.A. = __13cm2___ S.A. = ___50cm2__ S.A. = __113cm2_
S.A. = _____
V = ______
V = __4cm3____ V = __33cm3____ ___113cm3
V =V = _________
Ratio SA:V ___
Ratio SA:V ==_13:4 Ratio SA:V = Ratio SA:V =
Ratio SA:V = ___
or 3.25:1__ 50:33_or 1.51:1 _113:113 or 1:1__
S.A. = 4 (pi) r 2
1. As the spheres get larger what happens to the SA:V ratio?
Cell size and material exchange
The larger a cell
grows the more
trouble it has…
Moving all the
2nd problem: DNA overload
What are two problems that cell growth
causes for cells?
The larger a cell becomes, the more demands
the cell places on its _____ and the more trouble
the cell has moving enough _________and
_________ across the cell membrane.
What is viable solution for cells solve these
Cell Division – A larger cell splits into two smaller
The Cell Cycle and Mitosis
Homework 10-2-3 in guided reading
The Cell Cycle - series of events that cells
go through as they grow and divide
The cell cycle is
divided into two
period of the cell
M phase –
period of time
and cell division
Parts of Interphase
Synthesize new proteins and
Doing their jobs
Longest phase of cell cycle
Key proteins associated with
replication are made
Shortest of the 3 phases of
Organelles and molecules for
cell division are produced
Check-up phase before mitosis
Chromatin and Chromosomes
Chromatin - A complex of DNA and proteins
in the cell nucleus that condenses to form
chromosomes during cell division.
Chromosomes – Condensed Chromatin
They are the same stuff, just in different
Chromatin condenses in chomosomes
before mitosis begins
Different organisms have different #’s of
Humans cells – 46
Fruit Fly cells – 8
Carrot cells – 18
King Crab cells - 208
During the cell cycle (before
cell division can take place)
chromosomes are replicated
to form an identical copy of
Two identical copies of a
chromosome are called
“sister” chromatids – (one of
two identical “sister” parts
of a duplicated
Centromere - area where
the chromatids of a
M Phase, Cell Division and Mitosis
are a part of
In plant cells, a cell plate forms. The cell plate is
synthesized by the fusion of multiple membrane-
bounded vesicles. Their fusion supplies new plasma
membrane for each of the two daughter cells. Synthesis
of a new cell wall between the daughter cells then
occurs at the cell plate.
10-3 cell cycle regulation
Homework 10-3 guided reading workbook
1. The break down of a cell’s entire life is the
2. The phase of the cell cycle when the cell
is growing, replicating DNA and getting ready
for mitosis is _____________.
3-6. What are the four phases of Mitosis?
7. The process of a cell actually splitting in
two is called _______________.
Controls on Cell Division
How do cells know when to divide
and when not to?
Internal regulators – are proteins that
respond to events inside the cell.
Some proteins make sure cells do not enter
mitosis until all of the chromosomes have been
What stage of the cell cycle do you think these
Cyclins – (internal regulator) one of a family
of closely related proteins that regulate the
cell cycle in eukaryotic cells
Protein that periodically
rises and falls in
concentration in step with
the eukaryotic cell cycle.
Cyclins activate crucial
protein kinases (called
kinases, or CDK) and
thereby help control the
progression from one stage
of the cell cycle to the next.
Cascade of events!!
External regulators - Proteins that respond to
events outside the cell are called external
External regulators direct cells to speed up or slow
down the cell cycle.
Growth factors are among the most important
external regulators, which tell cells to speed up
division. When is this important?
Molecules found on the surfaces of neighboring
cells often have an opposite effect, causing cells to
slow down or stop their cell cycles.
Uncontrolled Cell Growth
Various forms of cancer have many causes
The common thread in all cancers is that
control over the cell cycle has broken down.
Over 50% of cancer cells have a defect in
the p53 gene.
Quiz on Thursday
HO due wednesday
p53 is a tumor
found mutated in
about half of
It encodes a gene
that is activated by
damaged DNA and
is involved in
progression of the
SRC, proto-oncogene tyrosine-protein kinase