Final answer:
Levothyroxine, a synthetic form of thyroxine, is correctly represented as a neutral molecule, which exist and is used in medical treatment for hypothyroidism. Thyroid hormones bind to intracellular receptors, not on the plasma membrane, making statement 14 false. Graves' disease is the condition causing excess thyroid hormone production.
Step-by-step explanation:
When discussing whether levothyroxine is drawn as a neutral molecule, the statement that such a molecule doesn't exist is false. Levothyroxine is a synthetic form of thyroxine (T4), a hormone produced by the thyroid gland, and it is commonly represented as a neutral molecule in chemical structures.
Thyroxine (T4) and Triiodothyronine (T3) do not bind to receptors on the plasma membrane of target cells. Instead, they enter the target cells and bind to intracellular thyroid hormone receptors that function by modulating gene expression. Therefore, statement 14 is false.
The disease that causes too much thyroid hormone to be produced is Graves' disease, making the correct answer B. Graves' disease is an autoimmune disorder that leads to overactivity of the thyroid gland (hyperthyroidism).