Cell Biology I
o How did people get to this certain piece of information?
o If you want to gain new information, you first have to define the question.
o Is it already know, what pieces of knowledge are already known and what is not.
o The next step is to design an experiment to test the question.
o Finally you can interpret your results and hopefully come to some knowledge.
o A review is a paper with which you state the current state of scientific knowledge. It
discusses experiments that are contradictive or in agreement with each other.
Cells
Cells come in different shapes and sizes, but they share common properties. Whilst we have
created an image of a “typical” cell, hardly any of the cells actually look like that.
Cells are membrane enclosed units of life. The membrane was the first thing to make life
possible. It also allows the cell to have the other basic features.
Cells have a metabolism. This metabolism is created by things – like proteins, sugars,
chemicals etc – entering and exciting the cell. Thanks to the metabolism, cells can grow and
divide to create even more cells.
The last basic cell feature, is the ability to respond to environmental signals and conduct
both internal and external communication.
In Cell Biology, there are different topics that will be discussed. In the research to gain
knowledge, there are always a number of questions that need to be answered.
Questions asked:
o What is new knowledge
o What happens;
How are things transported in and out of the cell?
How are they produced?
o How can we show this?
o Which factors are involved and what pathway is used?
o Why does it happen; for which reason or what is the consequence.
o Where does it happen in the cell; in the cytoplasm or in an organelle.
o Can we modify or manipulate the cell to be more efficient for our processes?
Cell biology is very interdisciplinary. It crosses ground with 4 major disciplines.
o Biochemistry; what factors are involved?
o Physiology; what is the purpose or the reason?
o Biotechnology; how to manipulate the cell?
o Biomedicine; why does an organism get sick and how can we modify the
organism or counteract the pathogen?
,The basic features in a cell are: DNA RNA Proteins Metabolites. Metabolites are
molecules produced or altered by the cell. The interplay between these factors is very
important.
The Prokaryotic cell is biochemically very flexible. It is typically small (1-5um) and forms a
single celled organism. It also has no membrane enclosed compartments.
You should know the ratio between different objects and understand that if one thing is
transported by the other, it will naturally be smaller. You should also know the size of the
object to determine whether you can use a certain technique.
Eukaryotic cells are typically larger (20-50um) and contain more enclosed compartments
than the eukaryotic cell. They work together to form multicellular organisms. The
eukaryotic cell is made up of different compartments:
o Nucleus; the membrane has pores. The DNA synthesis and transcriptions take place
here. It is about 10um big. The pores are responsible for the transport in and out of
the nucleus.
o Endoplasmic reticulum; is responsible for protein modification. It is important in
transport and for sorting what object belongs where. Therefore, it works closely
connected to protein synthesis. The membrane proteins are inserted in ER. It also
functions as the first control for any secreted proteins.
o What object can we find with optical light microscopy?
o Golgi; acts as the second stage control for secreted proteins. It also works with a
membrane system and has multiple folded membranes. It is responsible for
recognizing, modification and the transport of proteins. All transport to, form and
within golgi, is conducted by transport vesicles. It also has a cis and trans side.
o Mitochondria; conduct the energy metabolism and fatty acid metabolism/oxidation.
This double membrane system plays a big role in controlling the cell mainly by
producing ATP.
o Lysosome; one of the degradation sites of the cell. They are also hydrolytic enzymes
which allows them to fuse with other parts of the cell like with phagosomes. They
also take up old organelles that may form a danger to the cell.
o Transport vesicles; they transport proteins between compartments. They are crucial
for distribution of material and information. How are transport vesicles recognized?
How does the fusion work? Snare proteins are involved.
o Cytoskeleton; structures the cell, helps it to moved and allows transport within the
cell. There are different types of filaments (thick to thin)
Microtubuli
Keratine
Actine
o Chloroplast; photosynthesis. Capture energy form the sunlight. They have stacks of
membranes to harvest light and produce ATP.
o Cytosol; this is not an empty space, it contains a lot of molecules. It is crowded. Many
chemical reactions in the metabolism happen. Like glycolysis. A lot of the signal
transduction cascade happens in the cytosol.
,
, Model Organisms
Model organism (system) are used as a replacement when studying the original organism is
not practical. Therefore, to be used as a model organism, it must meet certain requirements:
o It should be easy to study or handle;
o It should possess the factors you wish to study. Otherwise it won’t be a useful thing
to study.
The model system is usually very well known in the research field. This makes it easier to
discuss problems you encounter in research.
Model systems are used because the information is too difficult to obtain from the original
organism. So, you do this in the easiest possible way and with the easiest organism.
Examples when you were to use a model organism are:
o When you want to study a genetic factor in mammals, but the generation time is way
too long.
o When you are interested in the cell cycle of eukaryotes, but using multi-cellular
organisms would complicate the experiment too much to be able to interpret the
results.
Other reasons to use Model organism include:
o Model systems are more time efficient;
o You can use a unicellular instead of multicellular;
o The experiment can be too expensive to do it without modelsystem;
o It may be unethical performed on the original organism, but nobody will bat an eye if
you kill 2000 yeast cells or bacteria;
o The interpretation may be too difficult without using model organisms;
o The experiment may be too dangerous.
Cell cultures and theoretical calculations are often not included in the lists of model
systems.
Escherichia coli
E. Coli is the most frequently used model system in Biology. This is mainly because they
have a very short generation time which allows for rapid growth and a shorter duration of
the experiment. Furthermore, it can be grown in autoclaved closed vials. This allows you to
make sure you have a homogenous defined population meaning that every single cell is
derived from one cell.
Further pros for using E. coli include the possibility for genetic modification/manipulation
and the fact that it is a well-known model system. This is helpful because if you encounter a
problem, you can easily ask other scientists for advice/help. Furthermore, the laboratory
strains of E. coli have been made non-pathogenic, making it safe to work with.
You can do a lot with E. coli. It is well known for the ability to study the metabolic pathway
as it owns prokaryotic specific features. You can study concepts like, cell motility and
propulsion and answer questions like: How do bacteria move? Or How is the flagellum
assembled?
o How did people get to this certain piece of information?
o If you want to gain new information, you first have to define the question.
o Is it already know, what pieces of knowledge are already known and what is not.
o The next step is to design an experiment to test the question.
o Finally you can interpret your results and hopefully come to some knowledge.
o A review is a paper with which you state the current state of scientific knowledge. It
discusses experiments that are contradictive or in agreement with each other.
Cells
Cells come in different shapes and sizes, but they share common properties. Whilst we have
created an image of a “typical” cell, hardly any of the cells actually look like that.
Cells are membrane enclosed units of life. The membrane was the first thing to make life
possible. It also allows the cell to have the other basic features.
Cells have a metabolism. This metabolism is created by things – like proteins, sugars,
chemicals etc – entering and exciting the cell. Thanks to the metabolism, cells can grow and
divide to create even more cells.
The last basic cell feature, is the ability to respond to environmental signals and conduct
both internal and external communication.
In Cell Biology, there are different topics that will be discussed. In the research to gain
knowledge, there are always a number of questions that need to be answered.
Questions asked:
o What is new knowledge
o What happens;
How are things transported in and out of the cell?
How are they produced?
o How can we show this?
o Which factors are involved and what pathway is used?
o Why does it happen; for which reason or what is the consequence.
o Where does it happen in the cell; in the cytoplasm or in an organelle.
o Can we modify or manipulate the cell to be more efficient for our processes?
Cell biology is very interdisciplinary. It crosses ground with 4 major disciplines.
o Biochemistry; what factors are involved?
o Physiology; what is the purpose or the reason?
o Biotechnology; how to manipulate the cell?
o Biomedicine; why does an organism get sick and how can we modify the
organism or counteract the pathogen?
,The basic features in a cell are: DNA RNA Proteins Metabolites. Metabolites are
molecules produced or altered by the cell. The interplay between these factors is very
important.
The Prokaryotic cell is biochemically very flexible. It is typically small (1-5um) and forms a
single celled organism. It also has no membrane enclosed compartments.
You should know the ratio between different objects and understand that if one thing is
transported by the other, it will naturally be smaller. You should also know the size of the
object to determine whether you can use a certain technique.
Eukaryotic cells are typically larger (20-50um) and contain more enclosed compartments
than the eukaryotic cell. They work together to form multicellular organisms. The
eukaryotic cell is made up of different compartments:
o Nucleus; the membrane has pores. The DNA synthesis and transcriptions take place
here. It is about 10um big. The pores are responsible for the transport in and out of
the nucleus.
o Endoplasmic reticulum; is responsible for protein modification. It is important in
transport and for sorting what object belongs where. Therefore, it works closely
connected to protein synthesis. The membrane proteins are inserted in ER. It also
functions as the first control for any secreted proteins.
o What object can we find with optical light microscopy?
o Golgi; acts as the second stage control for secreted proteins. It also works with a
membrane system and has multiple folded membranes. It is responsible for
recognizing, modification and the transport of proteins. All transport to, form and
within golgi, is conducted by transport vesicles. It also has a cis and trans side.
o Mitochondria; conduct the energy metabolism and fatty acid metabolism/oxidation.
This double membrane system plays a big role in controlling the cell mainly by
producing ATP.
o Lysosome; one of the degradation sites of the cell. They are also hydrolytic enzymes
which allows them to fuse with other parts of the cell like with phagosomes. They
also take up old organelles that may form a danger to the cell.
o Transport vesicles; they transport proteins between compartments. They are crucial
for distribution of material and information. How are transport vesicles recognized?
How does the fusion work? Snare proteins are involved.
o Cytoskeleton; structures the cell, helps it to moved and allows transport within the
cell. There are different types of filaments (thick to thin)
Microtubuli
Keratine
Actine
o Chloroplast; photosynthesis. Capture energy form the sunlight. They have stacks of
membranes to harvest light and produce ATP.
o Cytosol; this is not an empty space, it contains a lot of molecules. It is crowded. Many
chemical reactions in the metabolism happen. Like glycolysis. A lot of the signal
transduction cascade happens in the cytosol.
,
, Model Organisms
Model organism (system) are used as a replacement when studying the original organism is
not practical. Therefore, to be used as a model organism, it must meet certain requirements:
o It should be easy to study or handle;
o It should possess the factors you wish to study. Otherwise it won’t be a useful thing
to study.
The model system is usually very well known in the research field. This makes it easier to
discuss problems you encounter in research.
Model systems are used because the information is too difficult to obtain from the original
organism. So, you do this in the easiest possible way and with the easiest organism.
Examples when you were to use a model organism are:
o When you want to study a genetic factor in mammals, but the generation time is way
too long.
o When you are interested in the cell cycle of eukaryotes, but using multi-cellular
organisms would complicate the experiment too much to be able to interpret the
results.
Other reasons to use Model organism include:
o Model systems are more time efficient;
o You can use a unicellular instead of multicellular;
o The experiment can be too expensive to do it without modelsystem;
o It may be unethical performed on the original organism, but nobody will bat an eye if
you kill 2000 yeast cells or bacteria;
o The interpretation may be too difficult without using model organisms;
o The experiment may be too dangerous.
Cell cultures and theoretical calculations are often not included in the lists of model
systems.
Escherichia coli
E. Coli is the most frequently used model system in Biology. This is mainly because they
have a very short generation time which allows for rapid growth and a shorter duration of
the experiment. Furthermore, it can be grown in autoclaved closed vials. This allows you to
make sure you have a homogenous defined population meaning that every single cell is
derived from one cell.
Further pros for using E. coli include the possibility for genetic modification/manipulation
and the fact that it is a well-known model system. This is helpful because if you encounter a
problem, you can easily ask other scientists for advice/help. Furthermore, the laboratory
strains of E. coli have been made non-pathogenic, making it safe to work with.
You can do a lot with E. coli. It is well known for the ability to study the metabolic pathway
as it owns prokaryotic specific features. You can study concepts like, cell motility and
propulsion and answer questions like: How do bacteria move? Or How is the flagellum
assembled?
