Endoplasmic Reticulum

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Endoplasmic Reticulum
By Miranda Emeline
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Endoplasmic Reticulum

• AKA ER, is a network of membranes and sacs that
  loop back and forth.
• Two different regions
• Rough ER
• Smooth ER
• The ER is a part of a protein sorting pathway.

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• ERs Structure (general)
• The ER is very extensive and is continuous with
  the nuclear envelope.
• Contains many folds, but its membrane forms a
  single sheet enclosing a single closed sac. This
  internal space is called the ER lumen.
• Rough and smooth ER are usually interconnected.

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• ER Functions (general)
• The ER is responsible for production of protein
  and lipid components of nearly all of the cells
  organelles.
• Responsible for transporting proteins and
  carbohydrates to the Golgi apparatus, plasma
  membrane, lysosomes, and other necessary
  locations
• Folding of newly made proteins is made possible
  by several ER proteins
• WOW... isnt that amazing?!?!

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• Fun Fact (for all you future physicians)
• The endoplasmic reticulum found in muscle
  fibers is called sarcoplasmic reticulum

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Rough ER

• WHAT IS IT?
• Region of ER with ribosomes attached to its
  membrane.
• Site of protein synthesis (translation) and
  transport.
• Structure
• Series of flattened sacs.

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• Rough ER Functions
• Protein synthesis and transport after
  transcription, the mRNA exits the nucleus through
  small pores to enter the cytoplasm. At the
  ribosomes on the rough ER, the messenger RNA is
  translated into proteins.
• Proteins transported along the cytoskeleton to
  the Golgi in transport vesicles where they are
  further processed and packaged into lysosomes,
  peroxisomes, or secretory vesicles.
• Produces antibodies in leukocytes (white blood
  cells).
• Produces insulin in pancreatic cells.

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Smooth ERNot just the blob without the pretty
red dots on it

• Smooth ER Structure
• Region without ribosomes.
• Smooth ER Functions
• Synthesizes carbohydrates and lipids
• Transitional area for vesicles that transport
  ER products to various destinations
• Produces enzymes that help to detoxify certain
  compounds in liver cells.
• Assists in the contraction of muscle cells
• Synthesizes male and female hormones in brain
  cells

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ER Related Disorder

• Adrenoleukodystrophy a disorder of the
  peroxisomes due to the deposition of huge amounts
  of lipid material in the brain and spinal cord
  and the adrenal glands which results in dementia
  and adrenal failure.
• ER storage diseases (ERSDs) a group of
  genetically based disorders in which mutant
  proteins fail to pass the ER qualitycontrol
• Occurs as a consequence of misfolded proteins
  accumulating in the ER lumen.

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Source http//library.thinkquest.org/C004535/endo
plasmic_reticulum.html
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ER Protein Synthesis Transport
Source http//www.cat.cc.md.us/gkaiser/biotutori
als/eustruct/endomembanim.html
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Sources

• Cell Anatomy Endoplasmic Reticulum.
  http//library.thinkquest.
• org/C004535/endoplasmic_reticulum.html
  . 3 January 2005.
• Endoplasmic Reticulum. http//www.
  cellsalive.com/cells/
• er.htm. 2 January 2005.
• Journey Into the Cell. http//biology.about.com
  /library/weekly/
• aa041300a.htm. 2 January 2005.