Biology CLEP Prep Practice Exam 2025 - Free Biology CLEP Practice Questions and Study Guide

Unicellular organisms are single-celled organisms that carry out all essential life processes within one cell. This means that they are responsible for their own energy conversion. Photosynthesis, which is the process by which plants and some bacteria convert light energy into chemical energy, is not performed by unicellular organisms as they lack the necessary organelles such as chloroplasts. Respiration, which involves the breakdown of glucose to produce ATP, is also not the main energy conversion process in unicellular organisms as they do not have specialized structures for this process. Fermentation, which involves the breakdown of glucose without the use of oxygen, is a type of metabolism used by some unicellular organisms, but it is not the main form of energy conversion. Therefore, chemoautotrophy is the type of energy conversion performed by unicellular organisms, where they use chemicals such as hydrogen sulfide or ammonia to produce