The microparticle consists of a plasma membrane surrounding a small amount of cytosol.

* For example, in human erythrocytes the cytosolic side ( the side facing the cytosol ) of the plasma membrane consists mainly of phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol.

The viscosity of cytoplasm is roughly the same as pure water, although diffusion of small molecules through this liquid is about fourfold slower than in pure water, due mostly to collisions with the large numbers of macromolecules in the cytosol.

Although water is vital for life, the structure of this water in the cytosol is not well understood, mostly because methods such as nuclear magnetic resonance only give information on the average structure of water, and cannot measure local variations at the microscopic scale.

The nature of calcium in the cytosol means that it is active for only a very short time, meaning its free state concentration is very low and is mostly bound to organelle molecules like calreticulin when inactive.

Excess water can cross into the cytosol.

The cytosol is a complex mixture of cytoskeleton filaments, dissolved molecules, and water that fills much of the volume of a cell.

The cytosol is a gel, with a network of fibers dispersed in water.

The cytosol is a complex mixture of substances dissolved in water.

Although water forms the large majority of the cytosol, its structure and properties within cells is not well understood.

Most of the cytosol is water, which makes up about 70 % of the total volume of a typical cell.

However, others argue that the effects of the high concentrations of macromolecules in cells extend throughout the cytosol and that water in cells behaves very differently from the water in dilute solutions.

Due to this network of fibres and high concentrations of dissolved macromolecules, such as proteins, an effect called macromolecular crowding occurs and the cytosol does not act as an ideal solution.

The concentrations of ions such as sodium and potassium are different in the cytosol than in the extracellular fluid ; these differences in ion levels are important in processes such as osmoregulation and cell signaling.

The concentrations of the other ions in cytosol are quite different from those in extracellular fluid and the cytosol also contains much higher amounts of charged macromolecules such as proteins and nucleic acids than the outside of the cell.

The lysosome maintains this pH differential by pumping protons ( H < sup >+</ sup > ions ) from the cytosol across the membrane via proton pumps and chloride ion channels.

It is also called as Perimitochondrial space. Because the outer membrane is freely permeable to small molecules, the concentrations of small molecules such as ions and sugars in the intermembrane space is the same as the cytosol.

Although reuptake of Ca < sup > 2 +</ sup > by the ER ( concomitant with its release ) modulates the intensity of the puffs, thus insulating mitochondria to a certain degree from high Ca < sup > 2 +</ sup > exposure, the MAM often serves as a firewall that essentially buffers Ca < sup > 2 +</ sup > puffs by acting as a sink into which free ions released into the cytosol can be funneled .< ref name = Kopach > This Ca < sup > 2 +</ sup > tunneling occurs through the low-affinity Ca < sup > 2 +</ sup > receptor VDAC1, which recently has been shown to be physically tethered to the IP3R clusters on the ER membrane and enriched at the MAM.

The release of calcium ions from the endoplasmic reticulum into the cytosol results in its binding to signaling proteins that are then activated ; it is then sequestered in the smooth endoplasmic reticulum and the mitochondria.

This type of protein stimulates the production of cAMP, ultimately increasing the flow of calcium ions from the extracellular space and from the sarcoplasmic reticulum into the cytosol.

* Phosphodiesterase inhibitors such as caffeine directly affect the G-coupled signal transduction cascade by inhibiting the enzyme that catalyzes the breakdown of cAMP, again leading to the increased concentration of calcium ions in the cytosol.

) H + ions from the lumen of the thylakoid into the cytosol of a cyanobacterium or the stroma of a chloroplast.

Apoptosis occurs primarily via the increased intracellular concentrations of calcium ions, which flow into the cytosol through the activated glutamate receptors and lead to the activation of phospholipases, endonucleases, proteases, and thus the apoptotic cascade.

# Upon the arrival of an action potential at the presynaptic neuron terminal, voltage-dependent calcium channels open and Ca < sup > 2 +</ sup > ions flow from the extracellular fluid into the presynaptic neuron's cytosol.

# These receptors are ligand-gated ion channels, and when they bind acetylcholine, they open, allowing sodium ions to flow in and potassium ions to flow out of the muscle's cytosol.

Because the membrane permeability for potassium is much higher than that for other ions ( disregarding voltage-gated channels at this stage ), and because of the strong chemical gradient for potassium, potassium ions flow from the cytosol into the extracellular space carrying out positive charge, until their movement is balanced by build-up of negative charge on the inner surface of the membrane.

Mitochondrial proteins known as SMACs ( small mitochondria-derived activator of caspases ) are released into the cytosol following an increase in permeability.

The cytosol also contains the protein filaments that make up the cytoskeleton, as well as soluble proteins and small structures such as ribosomes, proteasomes, and the mysterious vault complexes.

The inclusions are small particles of insoluble substances suspended in the cytosol.

The material within the chloroplast is called the stroma, corresponding to the cytosol of the original bacterium, and contains one or more molecules of small circular DNA.

These include concentration gradients of small molecules such as calcium, large complexes of enzymes that act together to carry out metabolic pathways, and protein complexes such as proteasomes and carboxysomes that enclose and separate parts of the cytosol.

If the cell is growing rapidly, each complex also needs to transport about 6 newly assembled large and small ribosomal subunits per minute from the nucleus to the cytosol, where they are used to synthesize proteins.

* RNA polymerase III synthesizes tRNAs, rRNA 5S and other small RNAs found in the nucleus and cytosol.

They are a form of G-proteins found in the cytosol which are homologous to the alpha subunit of heterotrimeric G-proteins, but unlike the alpha subunit of G proteins, a small GTPase can function independently as a hydrolase enzyme to bind to and hydrolyze a guanosine triphosphate ( GTP ) to form guanosine diphosphate ( GDP ).

The proteasome degrades intracellular proteins into small peptides that are then released into the cytosol.

The cytosol is a crowded solution of many different types of molecules that fills much of the volume of cells.

The cytosol also contains large amounts of macromolecules, which can alter how molecules behave, through macromolecular crowding.

Although once thought to be a simple solution of molecules, multiple levels of organization exist in the cytosol.

The cell is additionally protected from any lysosomal acid hydrolases that drain into the cytosol, as these enzymes are pH-sensitive and do not function well or at all in the alkaline environment of the cytosol. This ensures that cytosolic molecules and organelles are not lysed in case there is leakage of the hydrolytic enzymes from the lysosome.

* A large central vacuole, a water-filled volume enclosed by a membrane known as the tonoplast maintains the cell's turgor, controls movement of molecules between the cytosol and sap, stores useful material and digests waste proteins and organelles.

These inserts are transcribed by enzymes of the host into new RNA molecules that enter the cytosol.

Secretion in bacterial species means the transport or translocation of effector molecules for example proteins, enzymes or toxins ( such as cholera toxin in pathogenic bacteria for example Vibrio cholerae ) from across the interior ( cytoplasm or cytosol ) of a bacterial cell to its exterior.

Large molecules synthesised in the cell body, intracellular components such as vesicles, and organelles such as mitochondria are too large ( and the cytosol too crowded ) to diffuse to their destinations.

* Hydrophilic molecules: water-soluble molecules, like cAMP, cGMP, IP < sub > 3 </ sub >, and Ca < sup > 2 +</ sup >, that are located within the cytosol

Peptides that fail to bind MHC class I molecules in the lumen of the endoplasmic reticulum ( ER ) are removed from the ER via the sec61 channel into the cytosol, where they might undergo further trimming in size, and might be translocated by TAP back into ER for binding to an MHC class I molecule.