[Campbell Biology P.124] According to the text, which statement correctly differentiates a k... | Practice Question

According to the text, which statement correctly differentiates a key structural feature of steroids from phospholipids, and accurately describes a function of each?

  • A: Steroids are characterized by a carbon skeleton of four fused rings and can act as precursors for hormones, while phospholipids form a bilayer that functions as a cellular boundary.
  • B: Steroids are primarily involved in energy storage, and phospholipids are the building blocks of DNA.
  • C: Steroids are polymers of amino acids, and phospholipids serve mainly as enzymes.
  • D: Both steroids and phospholipids are derived from simple sugars, with steroids providing structural support and phospholipids regulating metabolism.

Explanation

The text defines steroids by their 'carbon skeleton consisting of four fused rings' and notes cholesterol a steroid is a 'precursor from which other steroids, such as the vertebrate sex hormones, are synthesized'. For phospholipids, it states they are arranged in a 'bilayer' where they 'form a boundary between the cell and its external environment'. This aligns with option A.