Video Transcript
Which of the following best describes organisms that use heterotrophic nutrition? (A) They do not require food but survive off water alone. (B) They are able to synthesize their own food. (C) They obtain food from feeding on other organisms. Or (D) they consume a different form of food every day.
The question is asking us about a type of nutrition. So let’s start by reviewing the meaning of that term. Nutrition refers to how living organisms take in and use food in order to grow, reproduce, and maintain and repair themselves. There is enormous variety in the methods organisms use to obtain their food. But all organisms use cellular respiration to break down glucose in this food and release energy in the form of ATP.
When discussing nutrition, we can broadly classify organisms as either autotrophic or heterotrophic. You may remember that the prefix auto- means self and the term “troph” means food. So autotrophic organisms synthesize their own food. For example, plants and algae are autotrophs because they use photosynthesis to convert light energy from the Sun into food in the form of glucose. The glucose is then broken down via cellular respiration to release ATP.
In contrast, the prefix hetero- means different. So heterotrophic organisms get their nutrition by consuming other organisms or organic material. For example, humans are heterotrophs because we obtain nutrition by consuming other organisms, including plants, animals, and fungi. Our digestive system then breaks down this food to extract nutrients, such as proteins, lipids, carbohydrates, and minerals. And just as in autotrophs, some of the nutrients in this food will be broken down via cellular respiration to release energy in the form of ATP.
We now have enough information to pick the statement that best describes organisms that use heterotrophic nutrition. The correct answer is, they obtain food from feeding on other organisms.
