Question

this image shows how each of the three different types of human muscle cells appear under a light microscope.
which statement best summarizes why these human muscle cell types look different?
a the muscle cells may appear slightly different but the structure and function of each type is identical.
b the three types of muscle cells look different since they each have different dna contained in the nucleus.
c the three types of muscle cells appear different since they are present at different stages of the organisms development.
d the three types of muscle cells appear different since they are specialized to perform different functions in the human body.

Explanation:

• Option A: Incorrect. Different muscle cell types have distinct structures and functions. For example, skeletal muscle is striated and under voluntary control (for movement), smooth muscle is non - striated and in internal organs (for involuntary functions like peristalsis), and cardiac muscle is striated and in the heart (for pumping blood).
• Option B: Incorrect. All somatic cells in the human body (including different muscle cells) have the same DNA in the nucleus. Cell differentiation (not different DNA) leads to different cell types.
• Option C: Incorrect. The differences in muscle cell appearance are due to their specialized functions, not the stage of organism development.
• Option D: Correct. Cell specialization (cell differentiation) leads to cells with different structures that are adapted to perform specific functions. Skeletal muscle for movement, smooth muscle for internal organ functions, and cardiac muscle for heart function.

Answer:

D. The three types of muscle cells appear different since they are specialized to perform different functions in the human body.