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Summary Technologies in Bioscience and Chemistry
Summary of Technologies in Bioscience and Chemistry for BA3 Business Economics at the VUB.
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Voorbeeld 4 van de 118 pagina's
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Door: octavian-gabrielmatei • 1 jaar geleden
Voorbeeld van de inhoud
Technologies in Bioscience and ChemistryChapter 1: The Cell
1. What are cells?
Figuur 7.0 Fluorescentie kleuring van een cel
The cell
Cells are the smallest organized unit in bodies. You can find them in animals and in plants. They
are surrounded by membrane and they carry out a wide variety of functions during their
lifespan. Robert Hooke introduced the word “cell”. A cell means a very small area, which
reminded him of the tiny cavities in cork, the place where the monks sleep in a monastery.
They are the elementary particles of organisms.
Cells contain different organelles, and you directly see that there are some green areas and a
pink/purple spot. There are also membranes that keep the cell in a certain form.
Cel fractioning
1
,If you want to separate all these different organelles (when you want to seclude these
organelles), there exists a certain technique: cell fractioning.
You start with tissue cells (cells from an organ or a live tissue) and you bring them into a tube.
After homogenization and centrifugation, you end up with a homogenate solution. When you
do the centrifugation process very specifically (namely at 1000x the gravity force, or 1000g, for
10 minutes), you end up with pellet rich in nuclei and cellular debris. Nuclei are the heaviest
and biggest parts of a cell.
When you take out the supernatant and you do the centrifugation again (with a different timing
of 20min, and with a different gravity force, here 20 000g), you obtain a pellet rich in
mitochondria (and chloroplasts if cells are from a plant).
If you take out the supernatant again (60min and 80 000g), and do the centrifugation once
more, you end up with a pellet rich in microsomes (which are pieces of plasma membranes
and cells’ internal membranes).
Do it again for 3 hours with a gravity force of 150 000g, you will get a pellet rich in ribosomes.
These are the different pellets with the different types of organelles.
2. Types of cells:
Two types of cells: Prokaryote vs. eukaryote.
There exists even two types of cells in different organisms: plant cells and animal cells.
Plants have a specific metabolism: they do photosynthesis. Animal cells don’t do
photosynthesis.
Prokaryote:
Pro: something in an earlier stage (pro -> before).
Karyote: the nucleus.
è This is a cell in a state of not having a real nucleus, so it is a prokaryote.
A prokaryote cell
2
,A prokaryote cell is a very important type of cell. It is a bacteria.
It has some pili, which are the small hairs that are located all around the cell. At the bottom of
the cell are flagella, which are the organelles that the cell can use to move around.
Inside the cell, you have the nucleoid, which is the carrier of the genetic material. The nucleoid
is the DNA of the bacteria. It is not enclosed in the nucleus; it is free in the cell.
The “brown spots” are the ribosomes. They are important, as they bring proteins next to the
DNA. The DNA will use these proteins to duplicate the DNA.
Around the bacterial cell, you can see the plasma membrane. This membrane is important to
bring in certain substances or to draw out the waste of the cell.
You have the cell wall to protect the bacteria, as well as a very thin layer around, which is the
capsule. It is there to protect the bacteria from external outside products (chemical products,
or heat/cold, etc.).
The plasma membrane in the animal cell
The cell membrane is a layer that consists of different parts. The upper part is the hydrophilic
region; the region where there is possible contact with water (or the environment). You then
have the “real” membrane, or the hydrophobic region. Beneath it, you have again a hydrophilic
region, which has contact with the inside part of the. (Hydro = water, philic = friend of, phobic
= enemy of). à To separate these hydrophilic regions, you have the hydrophobic region, a
“fatty” part.
3
, Different types of transport into the cell membrane of the animal cell
There exists different types of transport into the cell membrane of the animal cell.
The first one is about transport. The under part is the inside of the cell and the upper part is
the environment (air or water). The outer part of the cell is the place where food will come in.
It’ll enter the cell and will follow the way of the transport molecules. (In: 3 pink transport
molecules coming into the cell. Out: The used products, organelles that are not sufficient
anymore will have to be evacuated and will move out of the cell.)
The second one is about connections. The green substance is fitting into the molecules, and
they will bring certain particles from outside of the cell, into the cell. These are connections (to
other substances). They are even important to “fit” one cell to another. A different cell could
be fitted to this cell using these connections. Different cells are making a tissue, and different
tissues are making an organ.
You also have the receptors, working with the key and lock model. This means that a certain
substance will completely stick into the receptor, and the response of this “sticking” is a certain
signal. A very interesting example is hormones. Hormones will stick on the receptor and will
enter the cell to give out certain signals (into the cell).
This also works with enzymes. They have a special key and lock model, and they will fix onto
molecules and make certain reactions into the cell.
Finally, you have the gap junctions who are the way one cell can be joined together. You see
this in plant cells, when you cut a leaf (make a transversal cut), you see all cells are sticking
together, and water transport is possible from one cell to another. This works with gap
junctions.
Eukaryote:
Eu: real
Karyote: nucleus
è This is a cell with a real nucleus.
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