Growth factors are local regulators that
A) are produced by the anterior pituitary.
B) are modified fatty acids that stimulate bone and cartilage growth.
C) are found on the surface of cancer cells and stimulate abnormal cell division.
D) bind to cell-surface receptors and stimulate growth and development of target cells.
E) convey messages between nerve cells.

Question

Quizplus · Accepted Answer

Growth factors are signaling molecules that bind to specific receptors on the surface of target cells and stimulate cell growth, proliferation, and differentiation in a variety of tissues. They are typically produced locally within the tissue where they act and play important roles in normal development, tissue repair, and regeneration.

Option A is incorrect because growth factors are not produced by the anterior pituitary, which mainly secretes hormones that regulate endocrine function. Option B is incorrect because modified fatty acids do not act as growth factors. Option C is incorrect because growth factors are not found on the surface of cancer cells, although some tumors may produce abnormally high levels of growth factors or express growth factor receptors at higher levels than normal cells. Option E is incorrect because growth factors are not typically involved in neuronal signaling, although some growth factors do play roles in the development and differentiation of specific types of neurons.

Growth Factors Are Local Regulators That