Carbohydrates are found in sugary and starchy foods. They contain the building block glucose. Glucose is an important monosaccharide which provides the body with energy. Excess glucose can be converted into glycogen and stored in the liver until needed. Protein consists of amino acids. These are important for building muscle tissue; proteins are in our cell membranes and make up hormones and enzymes in the body. Fats contain fatty acids and glycerol. Fats are needed for the nervous system to properly function and the reserve of fat beneath the skin is for insulation and stored energy. Vitamins, which are organic compounds, are considered coenzymes and assist enzymes in the chemical reactions in our bodies. A deficiency can lead to a disorder or nutritional disease. For example, a deficiency of Vitamin C can lead to scurvey, a disease that weakens capillaries in the body. Minerals are necessary inorganic elements necessary to maintain optimal health. For example, iron is necessary to produce hemoglobin, a transport pigment in the red blood cells.