1.1. People suffering from anaemia are generally lacking in dietary iron. It is recommended that they consume more red meat and green leafy vegetables to increase the iron levels in their blood.

Explain why one of the symptoms of anaemia would be fatigue.

1.2. At high altitudes, the partial pressure of oxygen in the air is substantially lower than at sea level. This means that the partial pressure of oxygen in the bloodstream is also much lower at high altitudes compared to at sea level. The partial pressure of oxygen at sea level is about 14.0 kPa, while at 10 000 metres above sea level it is about 4.0 kPa. Table 1 shows the percentage saturation of haemoglobin at different partial pressures of oxygen.

Table 1

With reference to Table 1, calculate the percentage decrease in the percentage saturation of haemoglobin as you travel from sea level to 10 000 metres above sea level.

Show your working.

1.3. Compare the different chemical elements found in proteins and carbohydrates.

1.4. Enzymes called proteases are able to break proteins down and they are often added to biological washing powders to remove protein-based stains from clothes.

Explain how these enzymes are able to break proteins down.