Endomembrane Systems
By: Cate R.
Lindsay M.
Alexandra L.
Alex D.
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Lysosomes
•Lysosomes are organelles bound by a single membrane.
•They are formed by the Golgi apparatus.
• They contain enzymes which break down larger molecules and worn out cell
parts.
•Lysosomes contain hydrolytic enzymes which are used in hydrolysis which is the
break down of proteins using water.
•They are only found in animal cells.
•They play an important role in the human body’s defence system because they
destroy harmful substances.
•There are over 30 hereditary illnesses linked to malfunctioning digestive enzymes
found in Lysosomes.
•One example of a illness is Tay-Sachs disease. This is caused by an enzyme
deficiency which results in the accumulation of waste materials. A build up of waste
in cells could cause brain damage.
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Smooth ER (SER)
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Smoother ER is found in all cells, and in each serves many purposes. The
network of branches of SER allows for storage of key enzymes and their
products.
Found especially in cells that specialize in secreting proteins
Smooth ER does not contain the ribosomes on its surface.
It is the structure which synthesizes fats and lipids.
Interconnected channels which consist of tubules and vesicles
The smooth ER is located in the cytoplasm
Many organelles are created by the membrane of the smooth endoplasmic
reticulum.
Increases surface area for the storage of enzymes and the products of
enzymes.
Obesity causes stress in both the rough and smooth ER; this stress results
in the suppression of the signals of insulin receptors, leading to insulin
resistance.
ER stress can be caused by infection, hypoxia (a shortage of oxygen in the
body), nutrient deprivation, exposure to chemical toxins and excess fats.
Rough ER (RER)
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RER is an interconnected network of vesicles which is found in many
eukaryotic cells and is. These vesicles are responsible for many specialized
functions and are composed of parallel membranes.
The basic structure of RER is similar to that of the plasma membrane.
There are evenly spaced protein manufactured ribosomes only attached to
the RER.
Many organelles are created by the membrane of the rough endoplasmic
reticulum.
Increases surface area for the storage of enzymes and the products of
enzymes.
Interconnected channels which consist of tubules and vesicles
The smooth ER is located in the cytoplasm
Golgi Apparatus
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The Golgi apparatus is an organelle found in many eukaryotic cells.
Each animal cell contains 10 to 20 Golgi bodies. Even plant cells may
contain several hundred Golgi bodies. Protists usually contain one or
very few Golgi bodies. Golgi are especially abundant in glandular
cells, which manufacture the products that they secrete.
The Golgi apparatus looks like a stack of flattened balloons, which are
actually membranous sacs in a pile formation.
The main function of the Golgi apparatus is to process and package
lipids and proteins from the rough endoplasmic reticulum.
The membranes of the cisternae (membranous folds of the Golgi
bodies) push together, pinching off smaller protein-filled sacs known
as vesicles. These vesicles then move to other locations in the cell,
distributing the newly synthesized molecules within them to their
appropriate destinations.
The Golgi apparatus has been linked to Lou Gherig’s disease, juvenile
diabetes, and several autoimmune diseases. Scientists are further
researching this possibility. It is unknown if the irreversible
fragmentation of the Golgi which leads to cell death is the cause or
effect of the above diseases.
A tribute to our fallen cells…
Bio 11 text
Bio 12 text
Living systems text
www.wikipedia.com
www.google.ca
http://shieldslab.aecom.yu.edu/shieldslab_res.html
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http://stke.sciencemag.org/cgi/content/abstract/204/255/tw372
www.hypoxia.net
http://www.mercola.com/2004/nov/3/obesity_diabetes.htm