#phospholipids

[fluorresense]

call me a phospholipid the way i

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[ninebaal-ex]

Lil Freax [625 - 630]

[void-gar]

Phospholipid painting

[42autisticfrogs]

phospholipid bilayer? but I hardly even know her! hahaha

[flarefloofer]

Y’know what I think is depressing? Theres no GOOD phospholipid earrings out there. I googled it. There’s these silver things that are labeled that but they’re boring.

I need like phospholipids close up that look like the diagrams we get in biology with big heads and the like blue and purple and yellow tails yknow?????

[lorasstudies]

Monday 11th October

Lessons today:

• biology from 12:45 until 14:00

As I only had one lesson today, I didn't get into college until around 11:30. I spent just under an hour making some flashcards for Chemistry and then I went over a Biology PowerPoint. In my lesson we were looking at the structure and function of different lipids which was actually really interesting! After that I went into town with a friend before going to band practice.

Song of the day:

Everybody Wants To Rule The World - Tears for Fears

[er-cryptid]

Phospholipid Bilayer Diagram

[as-studypeach]

Cell Membranes: the Bouncers of the Cell

The cell membrane, sometimes called the plasma membrane, surrounds and protects the interior organelles of the cell as well as controlling what goes in and out. Complex cells like eurkaryotes have membranes surrounding their organelles as well.

This image shows the basic structure of a cell membrane, which you have to know in detail for the A Level exam. The basic function is to regulate the movement of substances across them and separate the contents of the cell from its environment. 

As shown, the membrane is not just a single layer - instead, it is comprised of two layers of phospholipids (therefore conveniently called the phospholipid bilayer).

Phospholipid molecules are made from two fatty acid tails and a phosphate head. You will have learnt more about this in earlier units.  These phosphate head are hydrophilic (water-loving) whereas the fatty acid tails are hydrophobic (water-hating). When in water, they orientate themselves so that the heads are facing the water and the tails are away from it. This is how they form their bilayer, with heads out and tails in.

There are other molecules in the membrane. Proteins are embedded in the bilayer. Some span the whole membrane and are called intrinsic proteins, such as channel or carrier proteins, which are needed in transport processes that move substances across the membrane. Others stick out from the membrane surface and only go half way through, therefore called extrinsic proteins. These have specific functions like chemical receptors.

Some proteins and lipids have branches of sugar molecules attached to them. When attached to a lipid, these make glycolipids and when attached to proteins, these make glycoproteins. Sugar molecules are always on the outer surface of the membrane so can interact with arriving molecules, such as hormones or drugs.

Cell membranes also have another lipid-like substance called cholesterol. This provides stability by preventing too much movement of the other molecules in the membrane. Animal cells, rather than plant or prokaryotic cells, usually have the highest amounts of cholesterol.

This membrane structure is not just specific to around the cell. Eurkayotic cells have a phospholipid bilayer with embedded proteins surrounding the endoplasmic reticulum, Golgi apparatus, the nucleus, lyosomes and vacuoles.

The Fluid Mosaic Model is generally accepted as describing how membranes are arranged. 'Fluid' represents how some parts of the membrane can move around freely, if they are not attached to other parts of the cell, such as the phospholipids. ‘Mosaic' part is the mismatched pattern of proteins that is found in the bilayer.

Summary

The basic function of a cell membrane is to regulate the movement of substances across them and separate the contents of the cell from its environment.

It is comprised of two layers of phospholipids (therefore called the phospholipid bilayer).

Phospholipid molecules are made from hydrophobic two fatty acid tails and a hydrophillic phosphate head. When in water, they orientate themselves so that the heads are facing the water and the tails are away from it, forming a bilayer.

Proteins are embedded in the bilayer. Some span the whole membrane and are called intrinsic proteins, such as channel or carrier proteins, needed in transport. Others stick out from the membrane surface and only go half way through, therefore called extrinsic proteins. These have specific functions like chemical receptors.

Some proteins and lipids have branches of sugar molecules attached to them, making glyolipids and glycoproteins. Sugar molecules are always on the outer surface of the membrane so can interact with arriving molecules, such as hormones or drugs.

Cell membranes also have another lipid-like substance called cholesterol which provides stability by preventing too much movement of the other molecules in the membrane.

Eurkayotic cells have a phospholipid bilayer with embedded proteins surrounding the endoplasmic reticulum, Golgi apparatus, the nucleus, lyosomes and vacuoles.

The Fluid Mosaic Model is generally accepted as describing how membranes are arranged. 'Fluid' represents how some parts of the membrane can move around freely, if they are not attached to other parts of the cell, such as the phospholipids. ‘Mosaic' part is the mismatched pattern of proteins that is found in the bilayer.

Happy studying!