Investigation to find out how changes in the consumption of protein in the diet influence the excretion of urea in humans
Amelia Wilson U6HW
Centre Number: 28254
Candidate Number: 1121 06/05/2008
Investigation to find out how changes in the consumption of protein in the diet influence the excretion of urea in humans
Aim: to investigate how a change in the protein consumption by humans affects their excretion of urea. We will take into account the two protein classes; the 1st class being animal, and the 2nd class being plant (not all essential amino acids).
Prediction
The more protein consumed, the higher the intake of nitrogen, this Nitrogen is then lost from the body in the form of urea. Therefore an increase in protein the diet should lead to an increased concentration in the urea (after the intake becomes greater than the body requires). As the intake of protein increases the concentration of urea will also rise; and the more alkaline the pH of the urine.
Justification of the prediction
Increased consumption of dietary protein is linearly related to the production of urea and urea excretion is controlled by the kidney.
Urea + water ammonium carbonate
If excess protein is consumed, it cannot be stored in the body. The proteins are comprised of amino acids, which contain useful energy. To obtain this energy the liver removes the nitrogen from these amino acids, and this is excreted as urea. The process by which urea is formed is deamination. The amino-group is removed and combines with a hydrogen atom, this produces ammonia. In humans, Ammonia is extremely soluble and very toxic, which is why it must be converted into a less soluble and toxic compound – urea. However it must be excreted daily to prevent build up and this is done as the blood passes through the kidneys. The urea is extracted and then excreted.
