inorganic ions

Question 1

describe the roles of irons ions, sodium ions, and phosphate ions in cells. (5)

Answer 1

iron ions
1. haemoglobin binds/associates with oxygen
OR
haemoglobin transports/loads oxygen;

sodium ions
2. co-transport of glucose/amino acids (into cells);
3. because sodium moved out by active transport/Na-k pump;

phosphate ions
4. affects osmosis/water potential;
5. used in/to produce ATP;
6. joins nucleotides/in phosphodiester bond/in backbone of DNA/RNA/in nucleotides;

Question 2

a high concentration of sodium in the blood can affect blood volume and cause hypertension.
use your knowledge of water potential to suggest how high sodium concentrations in the medicines taken could affect blood volume. (3)

Answer 2

1. (sodium ions) lower the water potential (of blood);
2. water would move into the blood by osmosis (from cells/tissue fluid);
3. increasing the blood volume;