TOPIC 1-Inorganic ions

Question 1

Does an atom have an overall charge?

Answer 1

-No
-The number of protons is the same as the number of electrons

Question 2

When are atoms most stable?
How is this achieved?

Answer 2

-When their outer shells are full
-By either gaining or losing electrons from the outer orbital so it is full

Question 3

How are ions formed?

Answer 3

When an atom gains or loses an electron

Question 4

What is an isotope?

Answer 4

When atoms of an element have different numbers of neutrons

Question 5

What is an ion?

Answer 5

An atom/ a group of atoms that has an electrical charge

Question 6

What are some uses of isotopes in biology?

Answer 6

-Dating fossils-concentration of ions
-Evidence for semi-conservative DNA replication
-Gas bubbles in ice to determine the atmosphere
-C14 to trace the movement of carbon within a plant

Question 7

What are complex ions?

Answer 7

They contain more than one atom

Question 8

Give 2 examples of complex ions.

Answer 8

-Nitrate NO3-
-Phosphate PO4 3-

Question 9

What are phosphates linked to in other areas of the specification?

Answer 9

-Phospholipids
-DNA structure
-ATP

Question 10

What is the role of Iron ions in haemoglobin?

Answer 10

-Haemoglobin is a large protein that carries oxygen around the body in red blood cells
-It is made up of 4 different polypeptide chains, each with an iron ion in the centre
-FE2+
-The FE2+ binds to the oxygen in haemoglobin
-When oxygen is bound The FE2+ ion temporarily becomes an FE3+ ion until oxygen is released

Question 11

Where do inorganic ions occur?

Answer 11

-In solution in the cytoplasm and bodily fluids of organisms
-Some in high concentrations and others in very low concentrations (Depending on their role)

Question 12

Why does each type of ion have a specific function?

Answer 12

-Depends on its properties

Question 13

What is an ion with a positive charge called?

Answer 13

-A cation

Question 14

Give 2 examples of cations

Answer 14

-NA+, a sodium ion that has a charge of +1
-CA 2+, a calcium ion that has a charge of 2+

Question 15

What is an ion called that has a negative charge?

Answer 15

-An anion

Question 16

Give 2 examples of anions

Answer 16

-CL-, a chlorine ion has a charge of 1-
-PO4 3-, this is a phosphate ion that has a charge of 3-

Question 17

What is an inorganic ion?

Answer 17

-One that doesn’t contain carbon (although there are a few exceptions

Question 18

What is the role of hydrogen ions?

Answer 18

-pH is calculated based on the concentration of hydrogen ions, H+ in the environment
-The more H+ present, the lower the pH ( and the more acidic the environment)
-Enzyme-controlled reactions are all affected by pH

Question 19

What is the role of sodium ions?

Answer 19

-Glucose and amino acids need help when crossing the plasma membrane
-A molecule of glucose or amino acid can be transported into a cell across the cell surface membrane
-Alongside sodium ions Na+ (co-transport)

Question 20

What is the role of phosphate ions?

Answer 20

-When a phosphate ion is attached to another molecule
is known as a phosphate group
-DNA, RNA and ATP all contain phosphate groups
-It’s the bonds between phosphate groups that store energy in ATP
-The phosphate groups in DNA and RNA allow nucleotides to join up to form polynucleotides