Complete question:
Transmembrane proteins span the width of cell membranes. Four types of transmembrane proteins are shown in a section of cell membrane. Although these proteins have different specific functions, they all...
Options:
1. stop chemical reactions within the cell
2. synthesize molecules that signal other cells
3. help the cell interact with its external environment
4. remove large waste particles from the cytosplasm of the cell
<em>Note: You will find the section of the cell membrane as an attached file.</em>
Answer:
<em>3. help the cell interact with its external environment
</em>
Explanation:
In the section of the cell membrane shown here, we can visualize transmembrane proteins of different types.
Transmembrane proteins act in active and passive transport, connecting cells, and participating in signal transduction.
In the scheme, we can see channel proteins that act by passive transport (these proteins do not need energy to carry in or out substances. They do it according to an electrochemical gradient) and carrier proteins that act by active transport (these proteins do need energy to transport substances because they do it against an electrochemical gradient). These transmembrane proteins carry in those substances needed by the cells to properly perform their activities, and they can also carry out waste substances.
We can also see connective proteins linking the extracellular space with the intracellular space.
Each of these transmembrane proteins has different functions, but all of them are involved in the cell interaction with its external environment
.