Attracting Abundance

- 103 -

The Law

Belief - XV

Our Cellular Biology - XIV

In this post we will briefly know about the endomembrane sytem of the cells. we had referred to the other organelles inside the cells in an earlier post. We will take another look into the function of these organelles.

The endomembrane system divides the cell into functional and structural compartments, or organelles. In eukaryotes the organelles of the endomembrane system include: the nuclear membrane, the endoplasmic reticulum (ER), the Golgi apparatus, lysosomes, vesicles, endosomes and the cell membrane. 

The endoplasmic reticulum (ER) is an organelle found in the cells of eukaryotic organisms. It is an interconnected network of flattened sacs or tubes encased in membranes. These membranes are continuous, joining with the outer membrane of the nuclear membrane. ER occurs in almost every type of eukaryotic cell except red blood cells and sperm cells. 

Endoplasmic reticulum has two types, rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER). Rough ER is studded with ribosomes, the site of protein synthesis. Smooth ER doesn't have ribosomes and is very important to the process of metabolism. 

Endoplasmic reticulum has a number of jobs within the cell. This includes the folding and transport of various proteins, specifically carrying them to the Golgi apparatus.  

The ER is also responsible for marking these proteins that it transports with a signal sequence. Other proteins are headed outside the ER, so they are packed into transport vesicles and moved out of the cell via the cytoskeleton. 

Basically, the ER is the transportation system of the eukaryotic cell, and its proteins are contained within it until they are needed to move. 

The Golgi apparatus is an organelle present in most eukaryotic cells. It is made up of membrane-bound sacs, and is also called a Golgi body, Golgi complex, or dictyosome. 
The job of the Golgi apparatus is to process and bundle macro-molecules like proteins and lipids as they are synthesized within the cell. The Golgi apparatus is sometimes compared to a post office inside the cell since one major function is to modify, sort, and package proteins to be secreted. 

The Golgi apparatus is made up of sacs called cisternae (flattened membrane disks). Usually five to eight cisternae are present in one Golgi apparatus, but as high a number as sixty cisternae have been observed by scientists. These bundles of sacs have five distinct and functional regions, and each region has different enzymes to help it modify the contents, depending on where they are to end up.

This organelle is also important in other ways, specifically in the transport of lipids throughout the cell and the creation of lysosomes.

The Golgi complex works closely with the rough ER. When the ER makes a protein, a transition vesicle (a small fluid-filled bladder, sac, cyst, or vacuole within the body) is also made. It drifts through the cytoplasm to the Golgi apparatus where it gets absorbed. After the Golgi works on the molecules inside, it secretes a vesicle into the cytoplasm which releases the protein molecule out of the cell.

Lysosomes are organelles inside animal cells that are fully membrane-bound; they're not present in red blood cells. As far as cellular components go, lysosomes are a relatively new discovery. 

Lysosomes are sphere-shaped structures that contain acid hydrolases which are enzymes to break down biomolecules like proteins, nucleic acids, carbohydrates, and lipids, almost like a stomach digests food.

As the garbage disposal of the cell, lysosomes also break down left over cellular wastes, actually digesting the unwanted materials from throughout the cytoplasm and from outside of the cell, and destroying obsolete components inside the cell. They are humorously called the "suicide bags" or "suicide sacs" of the cell because they destroy leftover content.

Lysosomes are also in charge of cellular homeostasis, plasma membrane repair, cell signaling, and energy metabolism. These are actively related to maintaining health and fighting diseases in their host organisms. Depending on the job they'll do in the cell, lysosomes can vary greatly in size. The largest lysosomes can be as much as ten time larger than the smallest ones. 

Note: Haemostasis is the human body's response to blood vessel injury and bleeding. It involves a coordinated effort between platelets and numerous blood clotting proteins (or factors), resulting in the formation of a blood clot and subsequent stopping of the bleed.

Endosomes are membrane-bound vesicles, formed via a complex family of processes collectively known as endocytosis, and found in the cytoplasm of virtually every animal cell. It involves the invagination (folding inward) of a cell’s plasma membrane to surround macro-molecules or other matter diffusing through the extracellular fluid. The encircled foreign materials are then brought into the cell, and following a pinching-off of the membrane (termed budding), are released to the cytoplasm in a sac-like vesicle. The size of vesicles varies, and those larger than 100 nanometers in diameter are typically referred to as vacuoles.

Once freed into the cytoplasm, several small vesicles produced via endocytosis may come together to form a single entity. This endosome generally functions in one of two ways. Most commonly, endosomes transport their contents in a series of steps to a lysosome, which subsequently digests the materials. In other instances, however, endosomes are used by the cell to transport various substances between different portions of the external cell membrane.

Summarizing, the endomembrane system of eukaryotic cells consists of the ER,, the Golgi apparatus, and lysosomes. Membrane components, including proteins and lipids, are exchanged among these organelles and plasma membrane via vesicular transport with the help of molecular tags that direct specific components to their proper destination.

Namaste

hanggang sa muli

Prabir

2002 England Match Issue Signed World Cup Home Shirt Mills #2 (v Denmark)

Condition of shirt - Excellent

Size - XL

Condition details - Pristine material look and feel, printing is great, a couple of light marks

Made by - Umbro

Player - Leeds United right back and tough tackler Danny Mills #2

Player issue features - Correct player size flock print professionally heat pressed, 2002 FIFA World Cup Korea Japan sleeve match and Denmark v England 15.6.2002 match detail are fully embroidered, signed by members of the 2002 World Cup squad, vome from their personal collection of a former England international and coach who received the shirt as a gift - a signed letter verifying this can be provided

Notes - Extremely rare player shirt believed to have been issued to Mills for the 2002 World Cup Round of 16 match against Denmark played at Niigata Stadium on the 15th June '02. Mills, who had stepped into the team following an injury to first choice right back Gary Neville, played the full match as the Three Lions cruised into the Quarter Finals with an impressive display. England were rampant in the first half and led 3-0 at the break after a Thomas Sorensen own goal had put them ahead and then Owen and Heskey struck. Mill's emotions got the better of him in the second half as he picked up a yellow card for dissent in what was his 11th full international appearance. Unfortunately Sven's men were undone by Brazil and the three R's in the Quarter Finals. The full back went on to represent England 7 more times after the tournament also playing notably for Middlesbrough and Man City

Click on the link below:

2002 World Cup England Vs Denmark Match Worn Shirt