Video Transcript
A diagram outlining the basic structure of a eukaryotic cell is provided, with the major organelles labeled. What is the function of the smooth endoplasmic reticulum? (A) The smooth ER synthesizes, stores, and transports lipids and carbohydrates within the cell. (B) The smooth ER synthesizes and transports proteins through the cell. (C) The smooth ER provides the site for the aerobic stages of respiration. (D) The smooth ER transports modified proteins and lipids to the cell membrane.
Let us discuss the role of the endoplasmic reticulum in eukaryotic cells to answer our question correctly. You might remember that there are two types of endoplasmic reticulum: the smooth ER and the rough ER. As their names suggest, these structures are named because of their appearance. The surface of the rough endoplasmic reticulum appears to be covered with little dots, which are colored red in this diagram and indicated by the pink arrows. And this makes it look rough. These dots are in fact ribosomes, which are needed for the production of proteins. The main function of the rough ER is to fold proteins into their final functional shape and to transport some proteins through the cell.
The smooth endoplasmic reticulum does not have ribosomes on its surface, which is why it appears to be smooth. You can see this indicated by the green arrows. The smooth ER plays a role in the synthesis, storage, and transportation of lipids and carbohydrates. It is also involved in converting toxins into less toxic compounds that can then be excreted. This process is called detoxification.
Now that we have discussed the difference between the rough and smooth ER, let’s take a look at our answer choices. Answer choice (A) seems to be correct because it states that the smooth ER synthesizes, stores, and transports lipids and carbohydrates within the cell. But let’s look at the remaining options before making our final decision.
Answer choice (B) is incorrect because this describes the function of the rough endoplasmic reticulum. Answer choice (C) is incorrect because the site of aerobic respiration is the mitochondria and not the smooth ER. Answer choice (D) is also incorrect because this describes the function of the Golgi apparatus.
Therefore, the option that best describes the function of the smooth endoplasmic reticulum is given by answer choice (A). The smooth ER synthesizes, stores, and transports lipids and carbohydrates within the cell.
