2.1 Cell Theory
by Gabriella van Staalduinen
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2.1 Cell Theory
by using the SI
Units compare the
relative size of
thickness of cell membrane
up to100 μm
up to 10 μm
outline one therapeutic
use of stem cells
Where are stem cells found?
in bone marrow
Where stem cells can be used?
in bone marrow transplants to treat
people who have certain types of
What can kill the cancer cells?
high doses of chemotherapy
the normal cells in the bone marrow
What can the patient
do before he is treated
He can undergo a bone marrow harvest in
which stem cells are removed from the
bone marrow by using a needle which is
inserted into the hip bone
What is an alternative way to get stem cells?, Stem cells can be harvested
from a matching donor.
Outline of cell
All living organisms are composed of cells.
Cells are the smallest unit of life.
Cells come from pre-existing cells and cannot be
created from non-living material.
the importance of the
surface area to volume
ratio as a factor limiting
Surface area affects the rate at which
particles can enter and exit the cell
If the surface area to volume ratio gets too small then
substances won’t be able to enter the cell fast enough to fuel
the reactions and waste products will start to accumulate within
the cell as they will be produced faster than they can be
volume affects the rate at which material are made or used
within the cell, hence the chemical activity per unit of time
cells will not be able to lose heat fast
enough and so may overheat.
the rate of heat production/waste production/resource consumption of a
cell is a function of its volume, whereas the rate of exchange of
materials and energy (heat) is a function of its surface area
cells in multicellular organisms
differentiate to carry out
Rather than all cells carrying out all functions, tissues and organs
specialize to particular functions.
Specialized cells have switched on particular genes (expressed)
that correlate to these specialist functions.
These specific gene expressions produce particular shapes,
functions and adaptations within a cell.
It is an advantage for multicellular organisms as cells can
differentiate to be more efficient
Evidence for the cell theory
Scientists found out all living
organisms are made up of cells
IThrough experiment scientists proved that
cells cannot arise from non-living material
Multicellular organisms show
Multicellular orgamisms> organ
system> organ> tissue> cell
State that unicellular
organisms carry out all
the functions of life
Metabolism: all chemical
reactions which occur inside an
Response: (to the environment)
is essential to survival
Homeostasis: Maintaining a constant
internal environment e.g. temperature
molecules passed off to offspring
Growth: evident yet limited
Calculate the linear magnification of
drawings and the actual size of
specimens in images of known
1. Take measurement of
the drawing (width or
2. Take the same measurement
from the specimen
3. Convert units
Place values into the I AM calculation:, Magnification = Image size/actual size, Image size = actual size x magnification, Actual size = image size/magnification
State that stem cells retain the capacity to
divide and have the ability to differentiate along
Stem cells are the very early
This means that they are able to
differentiate into cells made for specific
For example, cells in bone marrow have the
capacity to differentiate into both red blood cells
and white blood cells.