Water

Question 1

Explain the five properties that make water important for organisms (5)

Answer 1

-Solvent, so metabolic reactions can occur
-High specific heat capacity, so buffers changes in temperature
-Large latent heat of vaporisation, so provide a cooling affect
-Cohesion so supports columns of water in plants
-Cohesion so produces surface tension supporting small organisms

Question 2

Describe the role of iron ions in cells (1)

Answer 2

-found in haemoglobin to help bind oxygen

Question 3

Describe the role of phosphate ions in cells (3)

Answer 3

-Forms ATP
- forms hydrophilic, part of bilayer
-joins nucleotides in phosphodiester backbone of DNA

Question 4

Describe the role of sodium ions in cells (3)

Answer 4

-involved in co-transport of glucose/amino acid
-move out by pump
-affectsosmosis