Haemoglobin Vs Nitrite
1. Background knowledge/theory:
Nitrite can be produced through a bacterial reduction from nitrate. This reduction can occur in the oral cavity of humans. Nitrate is commonly found in fertilisers for food crops so it’s also found on the outside of fruits and vegetables (Mygind, 1991). This is relevant because nitrite can have consequences for our overall health. It can react with secondary amines to form nitrosamines. Research has shown that some nitrosamines can cause cancer (Mygind, 1991).
Furthermore, in our blood there is a reaction between nitrite and haemoglobin. Nitrite can oxidise the haemoglobin in the blood to methaemoglobin which is incapable of binding with oxygen and therefore can’t transport oxygen from the lungs to the rest
of the cells in the body. In addition, there’s an enzyme which reduces methaemoglobin back to haemoglobin however infants lack this enzyme so ingesting nitrate can be fatal. In serious cases this leads to internal asphyxiation as the cells aren’t supplied with oxygen (Mygind, 1991).
From this I came up with the following research question: How does the concentration of nitrite in spit in my mouth depend of the number of chewing I do on 10 grams of conventionally grown lettuce? Here the independent variable is how many times I chew the lettuce and the dependent variable is the absorbance which is then turned into concentration of nitrite by calculations based on a standard curve. I hypothesise that initially the relationship between the number of times that I chew and the concentration of nitrite in my spit will be linear. However, towards the end I expect the curve to bend off as most of the nitrate, which by enzymes becomes nitrite, has been released.
Nitrite can be produced through a bacterial reduction from nitrate. This reduction can occur in the oral cavity of humans. Nitrate is commonly found in fertilisers for food crops so it’s also found on the outside of fruits and vegetables (Mygind, 1991). This is relevant because nitrite can have consequences for our overall health. It can react with secondary amines to form nitrosamines. Research has shown that some nitrosamines can cause cancer (Mygind, 1991).
Furthermore, in our blood there is a reaction between nitrite and haemoglobin. Nitrite can oxidise the haemoglobin in the blood to methaemoglobin which is incapable of binding with oxygen and therefore can’t transport oxygen from the lungs to the rest
of the cells in the body. In addition, there’s an enzyme which reduces methaemoglobin back to haemoglobin however infants lack this enzyme so ingesting nitrate can be fatal. In serious cases this leads to internal asphyxiation as the cells aren’t supplied with oxygen (Mygind, 1991).
From this I came up with the following research question: How does the concentration of nitrite in spit in my mouth depend of the number of chewing I do on 10 grams of conventionally grown lettuce? Here the independent variable is how many times I chew the lettuce and the dependent variable is the absorbance which is then turned into concentration of nitrite by calculations based on a standard curve. I hypothesise that initially the relationship between the number of times that I chew and the concentration of nitrite in my spit will be linear. However, towards the end I expect the curve to bend off as most of the nitrate, which by enzymes becomes nitrite, has been released.