Explain how carbohydrates are used by living organisms.

2 Answers
Jul 21, 2018

Carbohydrates are the primary energy source for most heterotrophic organisms.


Carbohydrates which include sugars and starches are the primary energy sources produced in plants and used by heterotrophic organisms.

Carbohydrates are composed of a basic chemical formula that typically contains a ratio of one Carbon atom for every two Hydrogen atoms and one Oxygen atom #C_1H_2O_1#. Basically one carbon atom for every one water molecule Carbon + Water = Carbohydrate.

Monosaccharides or Single Carbon Chain Sugars include Glucose #C_6H_12O_6#

Disaccharides or Double Carbon Chain Sugars include Sucrose #C_12H_22O_11#

Combining monosaccharides and disaccharides create Polysaccharides which are complex sugars called starches.

Jul 21, 2018

Refer to the explanation.


Carbohydrates, in particular glucose, are the main source of energy for nearly all living things.

Plants and other photosynthetic autotrophs produce glucose through photosynthesis, which they break down during aerobic cellular respiration to form ATP, the form of energy usable by cells. They also store glucose molecules in the form of starch, which is a glucose polymer. Cellulose is also a glucose polymer used by plant cells to form the cell walls of cells, which provide structural support. Cellulose and starch are both glucose polymers, but the way in which the glucose molecules are bonded differs.


Nearly all heterotrophs require carbohydrates, produced by photosynthetic autotrophs, for energy. Their cells break down glucose to form ATP. In animals, glucose is stored in the form of glycogen, which is a glucose polymer. It is similar to plant starch, except that it is highly branched.