Final answer:
A peptide/protein hormone that is polar is typically hydrophilic and lipophobic, meaning it is water-soluble and avoids lipid environments. It binds to cell surface receptors, unlike steroid and thyroid hormones, which are lipophilic and can cross the cell membrane.
Step-by-step explanation:
The correct option is B:
A peptide/protein hormone that is polar is typically hydrophilic and lipophobic. These properties mean the hormone is water-soluble and has an affinity for aqueous environments, while it avoids lipid-based environments such as cell membranes.
Peptide hormones are made of amino acids and have a structure that allows them to be soluble in water, thus they're hydrophilic. Because of their polarity, they cannot easily cross the lipid bilayer of cell membranes; therefore, they are lipophobic. Instead, these hormones interact with cells by binding to cell surface receptors. Such interactions trigger a variety of cellular responses.
A hydrophilic and lipophobic molecule would not easily diffuse through the cell membrane's lipid layer. This is in contrast to steroid hormones and thyroid hormones, which are hydrophobic and lipophilic, meaning they can pass through the cell membrane to interact with intracellular receptors.