Which provides long-term energy storage?
a. glycogen
b. glucagon
c. glucose
d. cellulose

Glycogen provides long-term energy storage.

Glycogen is an example of a carbohydrate which is a polysaccharide that acts as a long-term energy storage compound in animals.

Further Explanation Living organisms require energy in order to undertake their daily activities such as growth and development, locomotion, gaseous exchange, etc. To do so they obtain nutrients for short-term and long-term energy source. Carbohydrates are the major energy source for living organisms, however, living organisms may use other sources of energy such as proteins or fats when carbohydrates is out of stock or not available.  

Energy source in animals

Animals use simple carbohydrates such as glucose obtained from diet for short-term energy sources. These simple carbohydrates may also be stored for future use in the form of glycogen, which makes glycogen a long-term energy source, to be used when need arises. When glucose levels are low in the body hormones in the body trigger the breakdown of glycogen to glucose. Other sources of energy such as proteins and fats are used when carbohydrates storage is depleted, for example during starvation.

Energy source in plants

In plants, on the other hand, simple carbohydrates are similarly used as a short term source of energy. Additionally, simple molecules such as glucose are stored in the form of starch for long-term source of energy for the plants.  

Why other Choices are incorrect:

Glucagon  Glucagon is the hormone that increases the blood glucose level to avoid it from dropping below optimum level. The hormone acts on the liver to stimulate the breakdown of glycogen to glucose, a process called glycogenolysis, and the glucose is released to the blood stream. Glucose Glucose is a simple carbohydrate classified as monosaccharides. It acts as the short term source of energy in both plants and animals. It is readily broken down during the process of cellular respiration to yield energy in the form of ATP, which is then used to drive cellular processes. Cellulose Cellulose is an example of a complex carbohydrates known as polysaccharides. It is found in plants cells lining the cell wall of all plant cells which is one of the key distinguishing feature between plant cells and animal cells.

Keywords: Glycogen, Glucose, energy sources  

Learn more about:  Glycogen: link Role of glucose: link

Level: High school

Subject: Biology  

Topic: Cellular respiration