Video Transcript
Which of the following best defines the term organelle? (A) The smallest unit of a cell that provides energy and resources to the cell. (B) The semipermeable membrane that surrounds the cell and structures within the
cell. (C) A group of similar cells that work together to carry out a specific function. Or (D) a subcellular structure contained within a cell that has a particular
function.
This question asks about the definition of the term organelle. You might remember that organelles are only found in eukaryotes, plant and animal
cells, for example. Prokaryotic cells, on the other hand, do not contain organelles. Let’s discuss a few examples of organelles in order to answer our question.
The nucleus is one of the most important organelles in eukaryotic cells. This organelle houses all of the genetic information responsible for protein
synthesis and correct cell functioning.
Attached to the nucleus you might find structures such as the rough and smooth
endoplasmic reticulum. The rough and smooth endoplasmic reticulum are organelles responsible for the
transport within a cell. And they also function in protein and lipid synthesis, respectively.
Other organelles include mitochondria, ribosomes, and, in plant cells,
chloroplasts.
You may notice that our prokaryotic cell doesn’t contain any organelles. And the DNA is not contained within a nucleus, but it’s free in the cytoplasm.
Let’s have a look at our answer options to decide which gives the best definition for
the term organelle. Answers (A) and (B) refer to the functions of some organelles, though they are too
specific to encompass all organelles. Answer choice (C) is referring to a group of cells, which is not relevant to the
organelles each cell contains. Organelles are contained within cells so can be referred to as subcellular
structures. In addition, they all have specific roles and functions. Therefore, answer (D) provides the best definition of the term organelle: a
subcellular structure contained within a cell that has a particular function.
