inorganic ions

Question 1

what are inorganic ions?

Answer 1

inorganic ions are atoms or groups of atoms which have lost or gained electrons and therefore have an electrical charge

Question 2

what are the two types of ions and how are they formed?

Answer 2

atoms that have lost an electron have a positive charge and are called cations.
atoms that have gained electrons have a negative charge and are called anions.

Question 3

what can inorganic ions do and where are they found?

Answer 3

inorganic ions dissolve in water and are found in the cytoplasm of cells and in body fluids

Question 4

what do inorganic do + example?

Answer 4

inorganic ions carry out a number of essential functions eg calcium ions are needed for healthy bones and teeth

Question 5

do inorganic ions contain hydrocarbon groups?

Answer 5

inorganic ions do not contain hydrocarbon groups (most don’t contain carbon at all)

Question 6

name four inorganic ions

Answer 6

hydrogen (H)+
Iron (Fe)2+ , (Fe)3+
Sodium (Na)+
Phosphate (PO4)3-

Question 7

what are the properties of hydrogen ions (1) and how do these link to hydrogen ions’ roles (3)?

Answer 7

properties :
- the pH of a solution is calculated from the concentration of hydrogen ions in the solution. the higher the hydrogen ion concentration, the lower the pH.
link to roles :
- the higher the hydrogen ion concentration, the lower the pH. pH outside the normal range can denature proteins and slow down or stop enzyme controlled reactions.
- high concentrations of CO2 in the blood increases hydrogen ion concentration and lowers pH - which causes the Bohr shift seen in oxygen dissociation curves and causes the release of oxygen to the tissues.
- hydrogen ions play an important role in respiration and photosynthesis.

Question 8

what are the properties of iron ions (1) and how do these link to iron ions’ roles (1)?

Answer 8

properties :
haemoglobin is a large protein with a quaternary structure. it is made up from 4 polypeptide chains and 4 haem groups. the haem groups contain (Fe)2+. oxygen binds to the (Fe)2+.
link to roles :
- oxygen binding to the (Fe)2+ in haemoglobin is essential for the transport of oxygen. the binding of oxygen changes the shape of the haemoglobin molecule, making it easier for subsequent oxygen molecules to bind. this explains the shape of the oxygen dissociation curve.

Question 9

what are the properties of sodium ions (1) and how do these link to sodium ions’ roles (1)?

Answer 9

properties :
the carrier proteins that transport sodium ions across the membrane often do so with another molecule, this is co-transport.
link to roles :
glucose and amino acids are moved across cell membranes by co transport with sodium ions. this is essential for the efficient absorption of glucose in the small intestine.

Question 10

what are the properties of phosphate ions (3) and how do these link to phosphate ions’ roles (3)?

Answer 10

properties :
- phosphate groups are charged which means they are attracted to polar water molecules. in phospholipids the phosphate group forms the hydrophilic head.
- phosphates form high energy bonds with other phosphate molecules. these bonds are easily hydrolysed.
- addition of phosphate lowers activation energy.
link to roles :
- phosphate groups form part of the phospholipids that make up cell membranes. the phospholipids arrange themselves with the hydrophilic (charged) heads on the outside and the hydrophobic tails on the inside.
- phosphate groups are an essential part of ATP, RNA and DNA. in ATP the high energy bonds between the phosphate groups store energy from respiration and release it when required for functions such as active transport.
- phosphorylation of glucose in glycolysis is the first step in respiration.