Carbohydrates are organic compounds made of carbon, hydrogen, and oxygen, e.g. glucose.
Carbohydrates can be found in several places in the cell including the cell membrane which is composed of a bilipid layer of proteins and carbohydrates. Carbohydrates are attached to proteins and lipids on the outer bilipid layer.
Carbohydrates can also be found in the cell's mitochondria where they are broken down to simple sugars. Remember all cells require energy in order to carry out necessary cell activity. Energy is stored in the carbohydrates, fats, and proteins that we eat. Carbohydrates are broken down to generate energy or ATP.