Question

the rough endoplasmic reticulum is a cell structure that consists of folded membranes that contain ribosomes. what is the advantage of the folded membranes?
a. increases surface area in order to produce more proteins
b. decreases surface area in order to produce more proteins
c. increases volume of the endoplasmic reticulum in order to produce more energy
d. decreases volume of the endoplasmic reticulum in order to make more energy
justification:
the cell membrane consists of a lipid bilayer with embedded proteins. what is one reason that proteins are essential for the cell membrane to function properly?
a. proteins attach the cell membrane to the cell wall.
b. proteins prevent the cell membrane from breaking apart in water.
c. proteins allow certain substances to pass through the cell membrane.
d. proteins prevent gasses, including oxygen and carbon dioxide, from passing through the cell membrane.

Explanation:

For the first question:

• Proteins in the cell membrane have various functions. One key function is that they allow certain substances (like ions, polar molecules) to pass through the cell membrane. This is because the lipid bilayer is impermeable to most polar substances, and proteins act as channels or carriers.
• Option A is incorrect because cell membrane proteins are not for attaching to the cell wall (cell - wall - related structures are different). Option C is incorrect as proteins do not prevent the membrane from breaking apart (lipids and other factors play more role in membrane integrity). Option D is incorrect as oxygen and carbon dioxide pass through the lipid bilayer (they are non - polar and can diffuse through).

For the second question:

• The rough endoplasmic reticulum (RER) has ribosomes on its surface. The folded membranes (cisternae) increase the surface area. Since ribosomes are sites of protein synthesis, a larger surface area with more ribosomes (due to folded membranes) means more proteins can be synthesized.
• Option B and C are incorrect as the RER is not mainly about energy production (that's more of mitochondria's role). Option D is incorrect as increasing volume is not the main advantage (surface area is more relevant for protein - synthesis - related functions).

Answer:

For the first question: B. Proteins allow certain substances to pass through the cell membrane.
For the second question: A. increases surface area in order to produce more proteins.