Iron compound
* Some iron compounds are suspected carcinogens
  - used in vitamins
* are also the basis of a rich variety of natural colours, both in rocks and in nature
  - applied in wastewater treatment, usually as coagulants
  - essential to all life
  - used for several things
* can be black, brown, yellow, green, or purple.
* give the red rocks their color.
* taken orally can impair the absorption of tetracycline antibiotics.
+ Iron, Properties, Chemical compounds
  * Iron makes chemical compounds with other elements. Normally the other element oxidizes iron. Sometimes two electrons are taken and sometimes three. Compounds where iron has two electrons taken are called ferrous compounds. Compounds where iron has three electrons taken are called ferric compounds. Iron compounds can be black, brown, yellow, green, or purple
  - Uses, As compounds
  * Iron compounds are used for several things. Some iron compounds are used in vitamins

### iron ore:

Goethite
* forms red pseudo-hexagonal crystals a few microns across.
* is iron ore
* occurs as bog iron ore at several points along the Wisconsin River.

### irrational act:

Scientific discovery
* Most scientific discoveries are the process of slow and painstaking research.
* Scientific discoveries carry no moral signs
  - improve quality
* Some scientific discoveries lead to technology.
* finds special properties of chocolate crucial to a successful diet.
* is an irrational act
  - roughly comparable to the discovery of the Earth
* path traveled by many dedicated figures.

### irreducibly complex:

Molecular mechanism
* Most molecular mechanisms involve actions
  - in interaction
* Some molecular mechanisms involve amino acid substitution
* are irreducibly complex.
* solve problems.
* used by cells to spatially regulate gene expression.

### irregular, deadly heartbeat:

Ventricular arrhythmia
* are less common
  - more complex to treat
  - typically more serious conditions
* begin in the ventricles.
* can cause sudden death in someone who appeared previously fit and well.
* is an irregular, deadly heartbeat
  - cardiac arrhythmia
* occur in almost everyone
  - the heart's two lower chambers called the ventricles

Irreversibility
* is quality
  - said to be the measure of a revolution
* tends to reduce the magnitude of the temperature decrease.

### irreversible a:

Metabolic pathway
* Some metabolic pathways involve proteins.
* Some metabolic pathways produce hormones
  - steroid hormones
* are irreversible a
  - metabolism
* differ with age.
* involve a number of enzyme-catalyzed reactions.
* require enzymes to catalyze a series of reactions in sequence.

### irreversible problem:

Biliary atresia
* begins before birth.
* chronic, progressive liver problem that becomes evident shortly after birth.
* common indication in pediatric patients.
* is an irreversible problem
  - caused when the bile duct to the liver becomes inflamed
* is characterized by absent bile ducts most notable within the liver hilum
  - the absence of the large bile duct outside the liver
  - the closure or disappearance of the biliary system
* is the most common cause of chronic liver disease in neonates
  - jaundice that requires surgical treatment in infants
  - indication for liver transplant in children
* progressive inflammatory process that begins very soon after birth.
* rare condition that presents with jaundice in babies
  - disorder of infancy
* serious disease of the very young infant.