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Hi friends hope you're fine. In this video let us understand an interesting
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organelle the endoplasmic reticulum. Endoplasmic reticulum as you see is an interconnected network of tubules and flattened sacs that produce and process
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lipids and proteins in a new karyotic cell. At the end of the discussion you
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will be able to understand the definition, location, occurrence, origin, structure, presence or absence of riboforine proteins, function and diseases
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associated with rough endoplasmic reticulum and smooth endoplasmic reticulum within 5 to 10 minutes
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Let's begin with why this name rough endoplasmic reticulum. As you see this is a rough endoplasmic
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reticulum that is connected to the nuclear membrane. This rough endoplasmic reticulum
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is started with ribosomes on the surface. So it has a rough appearance when viewed under electron
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microscope that's why it is called as rough endoplasmic reticulum. So this is
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the smooth endoplasmic reticulum. Here it is without ribosome therefore the surface is smooth therefore called as smooth endoplasmic reticulum. Difference
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number two regarding the location and occurrence. Rough endoplasmic reticulum is in continuous connection as you see this is a nuclear membrane. So it is a
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continuous connection with nuclear membrane that is located near the nucleus started with ribosomes
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As ribosomes is present on rough endoplasmic reticulum, the function is protein synthesis
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Therefore RAR is abundant in protein synthesizing cells So this is SCR as you see this is SCR It is located close to the cell membrane Numerous SCR is found in lipid synthesizing cells like oil glands of skin
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SCR in smooth and striated muscle it is called as sarcoplasmic reticulum. SCR is located away
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from the nucleus close to cell membrane. Difference number three regarding the origin. RER is formed
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from nuclear membrane. So it is in continuity with the nuclear membrane. It is formed from the nuclear
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membrane. As a channel for transporting proteins, it is a part of endomembrane system starting from
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nuclear membrane, then moving to RER, then SCR, Colg apparatus and finally passing the materials to
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the vesicles and moving out of the cell. Whereas SCR is in continuous connection with RER. So this
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is the boundary. SCR is actually a continuation of RER but without ribosome. SCR as you see is a
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continuation of RER but without ribosome. Difference number four regarding the structure. RER is composed
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of cisternae. these flattened sacs are called cisternae with very few tubules. whereas SCR is
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made up of tubules. primarily it is made up of tubules, network of tubules with very few cisternae
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or flattened membrane vesicles. Difference number five regarding the presence or absence of ribophore
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proteins So this is a riboforin protein that is present on the surface of RER So it is a transmembrane protein that helps in the attachment of ribosome to the surface Therefore riboforine
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protein is present in RER. In the case of smooth endoplasmic reticulum, ribosomes
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are absent. Therefore, riboforine protein is also absent on the surface of smooth
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endoplasmic reticulum. Difference number six regarding the function of RER and SER. Rough endoplasmic reticulum is studded with ribosomes on the surface as
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you see here the mRNA is attached to the ribosomes on the surface of RER. RER is
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specifically involved in the synthesis of membrane and secretory proteins also the proteins that moves through the lumen of this RER is modified or it
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undergoes post translational modification in the lumen that includes addition of sulfate group or sulfation then protein folding glycosylation etc. The function
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of RER is the synthesis of membrane and security proteins. It is also involved in
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post translational modifications including sulfation glycosylation etc. and this RER is a part of endomembrane system starting from nuclear membrane
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and that is involved in channeling of proteins to different locations of the
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cell. The protein that is synthesized in RER is transferred to Golgi apparatus
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where it is further modified, addressed then it will be pinched off as vesicles
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and moved out of the cell in the case of security proteins or embedded on the membrane in case of membrane proteins The functions of smooth endoplasmic reticulum include synthesis and
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storage of fatty acids, phospholipids that is needed for the membrane and also synthesis of
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steroids. It's also involved in maintenance of calcium homeostasis. It's a prominent organelle
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that is involved in detoxification reactions. It detoxifies molecules such as alcohol, drugs and
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metabolic waste products. Difference number seven regarding the diseases associated with endoplasmic
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reticulum stress. Diseases like spondyloepimetaphysial dysplasia. It is due to the accumulation of
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misfolded collagen proteins in rough endoplasmic reticulum. It's a genetic disorder that lead to
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abnormal bonds primarily due to malfunctioning of RER. Prolonged ER stress is associated with diseases like Alzheimer's or neurodegeneration
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atherosclerosis, type 2 diabetes and the progression of cancer. As you see ER
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stress leads to misfolded proteins then there can be intracellular stress conditions and also hypoxia, acidosis, hydrogen sulfide production etc all
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leading to various diseases. So these are the seven differences between rough
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endoplasmic reticulum and smooth endoplasmic reticulum. If you find this video useful please consider subscribing this channel. Take care, stay blessed. Thank
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you so much for your attention. You are with BiologicSums4u.com
