Get more information on respiration in organisms homework help from biology online tutors at

Respiration in Organisms

Respiration is an essential component of life, without which an organism cannot exist. It is important to know that all living organisms are made up of cells. The cell is the smallest and functional unit of life. A cell performs all kinds of functions like digestion, excretion, reproduction and other catabolic and metabolic activities in organism’s body.

The cell requires energy which is obtained in the form of oxygen from the atmosphere. All plants and animals inhale oxygen from the air and exhale carbon dioxide into the air. This oxygen is taken up by each and every cell of our body and utilized to break down the food and release energy. This process is known as cellular respiration.

Carbohydrates present in the food are broken down into glucose during the digestion process. Glucose can be further broken down into carbon dioxide, water, and energy in the presence and absence of energy. This process in the presence oxygen is called as aerobic respiration and in the absence of oxygen is called as anaerobic respiration.

Aerobic respiration: Glucose                  

carbon dioxide (CO2) + water (H2O) + energy release

Anaerobic respiration: Glucose                 

alcohol + carbon dioxide (CO2) + energy release


Anaerobic respiration

A very well-known use of anaerobic respiration in today’s industrial world lies in making of beer and wine. Yeast, a single cell organism can live without oxygen for days by making use of the anaerobic respiration pathway. Hence such organisms are called as anaerobes.

Breathing in organisms

Breathing simply means inhalation and exhalation, i.e., taking in oxygen and exhaling carbon dioxide. All animals and humans breathe through nostrils. Organisms like fish breathe through their gills. The breathing rate of an organism can be measured by counting the number of times a person breathes in one minute. Breathing means one inhalation plus one exhalation.

A lot of exercises are based on controlling the breathing rate so as to supply abundant oxygen to all cells of the body. It is interesting to know that when we run or perform any physical activity, we lose our breath and thus inhale more oxygen. This results in speeding up of the food breakdown process resulting in the release of energy. And that is the explanation for why we tend to be hungrier after performing a physical task.

Respiration in Organisms Homework Help