Assistant Laboratory Animal Technician (ALAT) Practice Exam

What does the prefix 'ecto-' mean?

1. Inside

2. Outside

3. Between

4. Beyond

The correct answer is: Outside

The prefix 'ecto-' means 'outside' and is derived from Greek. In scientific and medical terminology, it is commonly used to denote things that are situated on the outer side or external to something else. For example, in anatomy, the term 'ectoderm' refers to the outermost layer of cells in an embryo. This prefix is utilized across various fields, such as biology, to describe structures or conditions that occur outside or external to something else. The other options provide different meanings that do not align with 'ecto-.' For instance, the meaning 'inside' pertains to 'endo-,' which indicates an internal location. The concept of 'between' relates more closely to 'inter-,' signifying something that is shared or occurring among two or more entities. Lastly, 'beyond' has a different connotation, often associated with surpassing or extending past a certain limit or scope, which is not captured by the prefix 'ecto-.'