Jail cell Membrane Role and Structure

Illustration by Alison Czinkota. ThoughtCo.

Updated on October 07, 2019

The cell membrane (plasma membrane) is a thin semi-permeable membrane that surrounds the cytoplasm of a cell. Its function is to protect the integrity of the interior of the cell by allowing certain substances into the cell while keeping other substances out. It as well serves equally a base of zipper for the cytoskeleton in some organisms and the jail cell wall in others. Thus the cell membrane also serves to help support the cell and help maintain its shape.​

Fundamental Takeaways

  • The prison cell membrane is a multifaceted membrane that envelopes a cell'south cytoplasm. It protects the integrity of the cell along with supporting the cell and helping to maintain the cell'due south shape.
  • Proteins and lipids are the major components of the prison cell membrane. The exact mix or ratio of proteins and lipids can vary depending on the part of a specific cell.
  • Phospholipids are of import components of cell membranes. They spontaneously arrange to grade a lipid bilayer that is semi-permeable such that only sure substances can lengthened through the membrane to the cell's interior.
  • Similar to the cell membrane, some jail cell organelles are surrounded by membranes. The nucleus and mitochondria are ii examples.

Another function of the membrane is to regulate cell growth through the balance of endocytosis and ​exocytosis. In endocytosis, lipids and proteins are removed from the cell membrane every bit substances are internalized. In exocytosis, vesicles containing lipids and proteins fuse with the cell membrane increasing prison cell size. Animal cells, plant cells, prokaryotic cells, and fungal cells have plasma membranes. Internal organelles are also encased by membranes.

Prison cell Membrane Structure

A molecular view of the cell membrane highlighting phospholipids, cholesterol, and intrinsic and extrinsic proteins.

Encyclopaedia Britannica / UIG / Getty Images

The cell membrane is primarily composed of a mix of proteins and lipids. Depending on the membrane's location and office in the torso, lipids can brand up anywhere from 20 to fourscore percent of the membrane, with the residue being proteins. While lipids help to give membranes their flexibility, proteins monitor and maintain the cell's chemic climate and assist in the transfer of molecules beyond the membrane.

Cell Membrane Lipids

Microscopic view of phospholipids.

Microscopic view of phospholipids.

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Phospholipids are a major component of cell membranes. Phospholipids form a lipid bilayer in which their hydrophilic (attracted to water) head areas spontaneously arrange to face the aqueous cytosol and the extracellular fluid, while their hydrophobic (repelled by h2o) tail areas confront away from the cytosol and extracellular fluid. The lipid bilayer is semi-permeable, assuasive only certain molecules to diffuse across the membrane.

Cholesterol is some other lipid component of brute cell membranes. Cholesterol molecules are selectively dispersed between membrane phospholipids. This helps to keep jail cell membranes from becoming stiff by preventing phospholipids from beingness too closely packed together. Cholesterol is non found in the membranes of plant cells.

Glycolipids are located on cell membrane surfaces and have a carbohydrate sugar chain attached to them. They help the cell to recognize other cells of the body.

Cell Membrane Proteins

Lipoproteins

Lipoproteins and PCSK9 bound to receptors.

MAURIZIO DE ANGELIS / SCIENCE Photo LIBRARY / Getty Images

The cell membrane contains ii types of associated proteins.Peripheral membrane proteins are exterior to and continued to the membrane by interactions with other proteins.Integral membrane proteins are inserted into the membrane and most pass through the membrane. Portions of these transmembrane proteins are exposed on both sides of the membrane. Cell membrane proteins accept a number of different functions.

Structural proteins help to give the cell support and shape.

Cell membranereceptor proteins assist cells communicate with their external surroundings through the use of hormones, neurotransmitters, and other signaling molecules.

Transport proteins, such equally globular proteins, transport molecules beyond cell membranes through facilitated diffusion.

Glycoproteins accept a carbohydrate chain fastened to them. They are embedded in the cell membrane and help in prison cell to cell communications and molecule transport across the membrane.

Eukaryotic Prison cell Structures

Chromosomes, artwork

Artwork of chromosomes.

Science Photo Library - SCIEPRO / Getty Images

The jail cell membrane is but one component of a cell. The post-obit cell structures can besides be found in a typical animal eukaryotic prison cell:

  • Centrioles—help to organize the assembly of microtubules.
  • Chromosomes—business firm cellular Deoxyribonucleic acid.
  • Cilia and Flagella—aid in cellular locomotion.
  • Endoplasmic Reticulum—synthesizes carbohydrates and lipids.
  • Golgi Apparatus—manufactures, stores and ships certain cellular products.
  • Lysosomes—digest cellular macromolecules.
  • Mitochondria—provide free energy for the jail cell.
  • Nucleus—controls cell growth and reproduction.
  • Peroxisomes—detoxify alcohol, form bile acrid, and use oxygen to intermission down fats.
  • Ribosomes—responsible for protein production via translation.

Sources

  • Reece, Jane B., and Neil A. Campbell. Campbell Biology. Benjamin Cummings, 2011.

Watch At present: What Is A Cell?