Question

what is one similarity between membrane carriers and pumps?

they change shape as they pass molecules across a membrane.

their regions that interact with the interior of the phospholipid bilayer are rich in hydrophilic r - groups.

their primary structure is made of nucleotides.

they are shaped to allow molecules of many sizes to pass through them.

Explanation:

• For the first option: Both membrane carriers (in facilitated diffusion) and pumps (in active transport) are transport proteins. They change their shape to move molecules across the membrane. For example, in the case of a glucose carrier, it binds to glucose, changes shape, and releases glucose on the other side of the membrane. In a sodium - potassium pump, it changes shape during the process of transporting sodium and potassium ions against their concentration gradients.
• For the second option: The interior of the phospholipid bilayer is hydrophobic. So, the regions of membrane carriers and pumps that interact with the interior of the phospholipid bilayer should be rich in hydrophobic R - groups (not hydrophilic) to be compatible with the hydrophobic environment of the bilayer.
• For the third option: The primary structure of proteins (which membrane carriers and pumps are) is made of amino acids, not nucleotides (nucleotides are the building blocks of nucleic acids like DNA and RNA).
• For the fourth option: Membrane carriers and pumps are specific. They are shaped to allow specific molecules (based on size, charge, and chemical properties) to pass through them. For example, a sodium - potassium pump specifically transports sodium and potassium ions and not just any molecule of any size.

Answer:

They change shape as they pass molecules across a membrane.