Endomembrane Systems

By: Cate R.Lindsay M.

Alexandra L.Alex D.

http://219.221.200.61/ywwy/zbsw(E)/pic/ech7-5.jpg

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.

http://219.221.200.61/ywwy/zbsw(E)/pic/ech7-5.jpg

Smooth ER (SER)

• 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)• 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• 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

http://219.221.200.61/ywwy/zbsw(E)/pic/ech7-5.jpg

http://stke.sciencemag.org/cgi/content/abstract/204/255/tw372

www.hypoxia.net

http://www.mercola.com/2004/nov/3/obesity_diabetes.htm