Biological molecules - inorganic ions

Question 1

Where are inorganic ions found?

Answer 1

They are found in solution in the cytoplasm of cells + in the body fluids of organisms

Question 2

Describe the structure of iron ions and where they are found

Answer 2

• Found in the large protein haemoglobin

- Each of the 4 polypeptide chains which make up haemoglobin has an Fe2+ ion in its centre

Question 3

Describe the function of iron in haemoglobin

Answer 3

• Fe2+ is the part of the haemoglobin which actually bonds to oxygen
• Whilst oxygen is bonded to the Fe2+ ion the ion temporarily becomes Fe3+

Question 4

Describe the function of hydrogen ions

Answer 4

H+ ions are sometimes concentrated to facilitate certain enzyme reactions (involved in pH)

Question 5

Describe the function of sodium ions

Answer 5

• To transport large molecules e.g glucose + amino acids across cell membranes
• Na+ ions can travel through relatively easily + can take larger molecules with them
• This is called co-transport

Question 6

Where are phosphate ions usually found?

Answer 6

• Whenever a phosphate ion is attached to a molecule it is called a phosphate group
• There are phosphate groups in DNA, RNA + ATP