Question

select all that apply
choose all functions typically carried out by membrane proteins.

□ code for the production of new polynucleotides
□ connect adjacent cells and hold them together
□ transport oxygen into the cell
□ attach the membrane to the cytoskeleton
□ receive external chemical messages

Explanation:

1. Analyze "Code for the production of new polynucleotides": DNA/RNA (polynucleotides) are coded by nucleic acids, not membrane proteins. Eliminate this.
2. Analyze "Connect adjacent cells and hold them together": Membrane proteins like cell - adhesion molecules do this. Include this.
3. Analyze "Transport oxygen into the cell": Oxygen is non - polar and diffuses freely, no membrane protein needed for its transport. Eliminate this.
4. Analyze "Attach the membrane to the cytoskeleton": Membrane proteins (like anchor proteins) perform this function. Include this.
5. Analyze "Receive external chemical messages": Receptor proteins (membrane proteins) bind to external signaling molecules. Include this.

Answer:

• Connect adjacent cells and hold them together
• Attach the membrane to the cytoskeleton
• Receive external chemical messages