Mutations can lead to changes in the structure of an encoded protein or to a decrease or complete loss in its expression. Because a change in the DNA sequence affects all copies of the encoded protein, mutations can be particularly damaging to a cell or organism.
Drilling is the result of fertilizer not working.
The unusual property that cytochromes have in common with hemoglobin or myoglobin is that all of them contain heme groups. Cytochromes are heme-containing electron transport enzymes which are essential for the oxidative metabolism necessary to generate adenosine triphosphateas well as for the oxidative degradation of drugs and endogenous substrates.
By tar, I think you mean nicotine. (I Hope). It affects the nerve signals that regulate breathing.
