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Why Pancreatic Cells Have More Rough Endoplasmic Reticulum

Why Pancreatic Cells Have More Rough Endoplasmic Reticulum

Recently, a question was sent in by one of our readers:

It has been found out that certain cells of the pancreas, which synthesize and release digestive enzymes (proteins), have more rough endoplasmic reticulum and golgi apparati than other cells. Why?

This is a really good question and it highlights the importance of knowing your cell biology and using that knowledge to make conclusions about cell structure relating to specialised cell function.

Before I answer this question, I would like to talk more in general terms how to use your knowledge to draw logical conclusions in cell biology.

The structure of a cell can tell us a lot about its specific functions as every component has a purpose in the functioning of the cell. Cytoskeleton helps maintain a cell’s shape and structure; microvilli increase surface area for absorption and secretion; and cilia aid movement.

Organelles also have specialised functions, for example:

Nucleus – Cell signalling centre and DNA container, controls cell functions such as synthesis and cell replication

Mitochondria – ATP synthesis (energy production)

Rough Endoplasmic Reticulum – Translation and folding of proteins

Smooth Endoplasmic Rediculum – Lipid synthesis

Golgi Apparatus – Protein sorting, modification and packaging for secretion

Vacuole – Exocytosis and endocytosis including phagocytosis in macrophages

Lysosome – breakdown of large molecules such as proteins or polysacciarides

Ribosome – Protein synthesis (tRNA->Protein)

Now, keeping this in mind, consider the functions and structures of certain specialised cells. You can use this information to draw a logical conclusion about how the structure of the cell relates to its function. Here are some examples:

Macrophages – These cells have many enzyme-filled lysosomes in order to break down foreign bodies.

A Macrophage Cell

Mature Red Blood Cells – These cells are containers for haemoglobin. In order to maximise their carrying capacity and surface area for Oxygen-Carbon dioxide exchange, they have ejected their nucleus prior to entering the blood stream.

Nerve cells – Nerve cells are very active; they need a lot of energy and thus, they have large numbers of mitochondria in order to be supplied quickly with the large amounts of ATP needed to drive their sodium/potassium pumps.

Learning how to draw these conclusions is very useful as it can help you quickly work out a potential, logical answer to a question, even if you haven’t been taught the answer directly. Remember though that if you aren’t sure, it is always best to ask as there may be some strange, obscure reason that something occurs that deviates from this way of thinking.

Now, back to our question. Using this way of thinking, we can come to the logical conclusion that because pancreatic secretory cells are making large amounts of enzymes, which are proteins, they would need a large number of ribosomes to translate tRNA to protein, lots of rough endoplasmic reticulum to fold the protein and many golgi to prepare and package the proteins for secretion. That is the logical conclusion as to why they have so many of these particular organelles.

Now, there may be an additional reason for this however, this is my theory as to why this is so.

Hope it helps. Happy studying! 🙂

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