Inorganic ions in

animal Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, ...

s and

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

s are

ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

s necessary for vital cellular activity. In body tissues, ions are also known as

electrolyte An electrolyte is a substance that conducts electricity through the movement of ions, but not through the movement of electrons. This includes most soluble Salt (chemistry), salts, acids, and Base (chemistry), bases, dissolved in a polar solven ...

s, essential for the electrical activity needed to support muscle contractions and neuron activation. They contribute to

osmotic pressure Osmotic pressure is the minimum pressure which needs to be applied to a Solution (chemistry), solution to prevent the inward flow of its pure solvent across a semipermeable membrane. It is also defined as the measure of the tendency of a soluti ...

body fluid Body fluids, bodily fluids, or biofluids, sometimes body liquids, are liquids within the Body (biology), body of an organism. In lean healthy adult men, the total body water is about 60% (60–67%) of the total Human body weight, body weight; it ...

s as well as performing a number of other important functions. Below is a list of some of the most important ions for living things as well as examples of their functions: * Ca²⁺calcium ions are a component of

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...

s and

teeth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

. They also function as biological messengers, as do most of the ions listed below. (See Hypocalcaemia.) * Zn²⁺ - zinc ions are found in very small concentrations in the body, and their main purpose is that of an antioxidant; the zinc ions act as antioxidants both generally and for liver specific

pro-oxidant Pro-oxidants are chemicals that induce oxidative stress, either by generating reactive oxygen species or by inhibiting antioxidant systems. The oxidative stress produced by these chemicals can damage cells and tissues, for example, an overdose of ...

s. Zinc ions can also act as an antioxidant-like stabilizer for some macro-molecules which bind zinc ions with high affinity, especially in

cysteine Cysteine (; symbol Cys or C) is a semiessential proteinogenic amino acid with the chemical formula, formula . The thiol side chain in cysteine enables the formation of Disulfide, disulfide bonds, and often participates in enzymatic reactions as ...

-rich binding sites. These binding sites use these zinc ions as a stabilizer to protein folds, making these protein motifs more rigid in structure. These structures include

zinc finger A zinc finger is a small protein structural motif that is characterized by the coordination of one or more zinc ions (Zn2+) which stabilizes the fold. The term ''zinc finger'' was originally coined to describe the finger-like appearance of a ...

s, and have several different conformations. * K⁺potassium ions' main function in animals is osmotic balance, particularly in the

kidneys In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and right in the retro ...

. (See

Hypokalemia Hypokalemia is a low level of potassium (K+) in the blood serum. Mild low potassium does not typically cause symptoms. Symptoms may include feeling tired, leg cramps, weakness, and constipation. Low potassium also increases the risk of an a ...

.) * Na⁺sodium ions have a similar role to potassium ions. (See Sodium deficiency.) * Mn²⁺- manganese ions are seen being used as stabilizer for varying protein configurations. However, manganese ion overexposure is linked to several

neurodegenerative A neurodegenerative disease is caused by the progressive loss of neurons, in the process known as neurodegeneration. Neuronal damage may also ultimately result in their death. Neurodegenerative diseases include amyotrophic lateral sclerosis, mul ...

diseases such as

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor system, motor and non-motor systems. Symptoms typically develop gradually and non-motor issues become ...

. * Mg²⁺ magnesium ions are a component of

chlorophyll Chlorophyll is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words (, "pale green") and (, "leaf"). Chlorophyll allows plants to absorb energy ...

. (See Magnesium deficiency (plants)) * Cl⁻ inability to transport chloride ions in humans manifests itself as

cystic fibrosis Cystic fibrosis (CF) is a genetic disorder inherited in an autosomal recessive manner that impairs the normal clearance of Sputum, mucus from the lungs, which facilitates the colonization and infection of the lungs by bacteria, notably ''Staphy ...

(CF) * the shells of sea creatures are

calcium carbonate Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...

. In blood approximately 85% of

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

, is converted into aqueous carbonate ions (an

acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...

solution Solution may refer to: * Solution (chemistry), a mixture where one substance is dissolved in another * Solution (equation), in mathematics ** Numerical solution, in numerical analysis, approximate solutions within specified error bounds * Solu ...

), allowing a greater rate of transportation. * Co²⁺- cobalt ions are present in the human body in amounts from 1 to 2 mg. Cobalt is observed in the heart, liver, kidney, and spleen, and considerably smaller quantities in the pancreas, brain, and serum. Cobalt is a necessary component of vitamin B₁₂ and a fundamental coenzyme of cell

mitosis Mitosis () is a part of the cell cycle in eukaryote, eukaryotic cells in which replicated chromosomes are separated into two new Cell nucleus, nuclei. Cell division by mitosis is an equational division which gives rise to genetically identic ...

. Cobalt is crucial for amino acid formation and some proteins to create

myelin sheath Myelin Sheath ( ) is a lipid-rich material that in most vertebrates surrounds the axons of neurons to insulate them and increase the rate at which electrical impulses (called action potentials) pass along the axon. The myelinated axon can be lik ...

in nerve cells. Cobalt also plays a role in creating

neurotransmitter A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a Chemical synapse, synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell. Neurotra ...

s, which are vital for proper function within the organism. *

adenosine triphosphate Adenosine triphosphate (ATP) is a nucleoside triphosphate that provides energy to drive and support many processes in living cell (biology), cells, such as muscle contraction, nerve impulse propagation, and chemical synthesis. Found in all known ...

(ATP) is a common molecule which stores energy in an accessible form.

Bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...

calcium phosphate The term calcium phosphate refers to a family of materials and minerals containing calcium ions (Ca2+) together with inorganic phosphate anions. Some so-called calcium phosphates contain oxide and hydroxide as well. Calcium phosphates are white ...

. * Fe²⁺/Fe³⁺as found in

haemoglobin Hemoglobin (haemoglobin, Hb or Hgb) is a protein containing iron that facilitates the transportation of oxygen in red blood cells. Almost all vertebrates contain hemoglobin, with the sole exception of the fish family Channichthyidae. Hemoglobi ...

, the main oxygen carrying molecule has a central iron ion. * source of nitrogen in plants for the synthesis of proteins.

Biological functions of inorganic ions

Ion channels

K⁺ channels

Potassium ion channels play a key role in maintaining the membrane's electric potential. These ion channels are present in many various biological systems. They frequently play a role in regulation of cellular level processes, many of these processes including muscle relaxation, hypertension, insulin secretion etc. Some examples of potassium ion channels within biological systems include K_ATP channels,

BK channel BK channels (big potassium), are large conductance calcium-activated potassium channels, and is also known as BKCa, Maxi-K, slo1, or Kca1.1. BK channels are voltage-gated potassium channels that conduct large amounts of potassium ions (K+) ...

s, and ether-a-go-go potassium channels

Na⁺ channels

Sodium ion channels provide an integral service through the body, as they transmit depolarizing impulses at the cellular and intracellular level. This allows sodium ions to coordinate much more intensive processes such as movement and cognition. Sodium ion channels consist of various subunits, however, only the principle subunit is required for function. These sodium ion channels consist of four internally homologous domains, each of which containing six transmembrane segments and resembling a single subunit of a voltage-dependent potassium ion channel. The four domains fold together, forming a central pore. That central pore of the sodium ions dictates the selectivity of the channel: both

ionic radius Ionic radius, ''r''ion, is the radius of a monatomic ion in an ionic crystal structure. Although neither atoms nor ions have sharp boundaries, they are treated as if they were hard spheres with radii such that the sum of ionic radii of the cati ...

and ionic charge are key in channel selectivity.

Cl⁻ channels

Chloride ion channels vary from many other ion channels due to being controlled by the anionic chloride ions. Chloride ion channels are pore-forming membrane proteins that allow the

passive transport Passive transport is a type of membrane transport that does not require energy to move substances across cell membranes. Instead of using cellular energy, like active transport, passive transport relies on the second law of thermodynamics to ...

of chloride ions across biological membranes. Chloride ion channels involve both voltage-gated and

ligand-gated Ligand-gated ion channels (LICs, LGIC), also commonly referred to as ionotropic receptors, are a group of transmembrane ion-channel proteins which open to allow ions such as Na+, K+, Ca2+, and/or Cl− to pass through the membrane in res ...

mechanisms to transport the ions across cellular membranes. Chloride ion channels have been found to play crucial roles in the development of human diseases, for example, mutations in the genes encoding chloride ion channels lead to a variety of deleterious diseases in muscle, kidney, bone, and brain, including

osteoporosis Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to more porous bone, and consequent increase in Bone fracture, fracture risk. It is the most common reason f ...

, and

epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...

, and similarly their activation is supposed to be responsible for the progression of

glioma A glioma is a type of primary tumor that starts in the glial cells of the brain or spinal cord. They are malignant but some are extremely slow to develop. Gliomas comprise about 30% of all brain and central nervous system tumors and 80% of ...

in the brain and the growth of malaria-parasite in the red blood cells. Currently, chloride ion channels are not completely understood, and more research is necessary.

References

{{Reflist Ions Cell biology Signal transduction

Biological functions of inorganic ions

Ion channels

K+ channels

Na+ channels

Cl− channels

See also

References

K⁺ channels

Na⁺ channels

Cl⁻ channels