Bacteria are grouped into two catgories reflecting structural features of their cells. Bacteria are classified as Gram-positive or Gram-negative based on whether or not they retain the crystal violet dye used in the Gram stain procedure. Cell wall structure determines the ability to retain the dye, thus cell wall structure is the basis of categorization into Gram-postive (G+) and Gram-negative (G-).

Which of the following occurs only in Gram-negative bacteria?

(A) Peptidoglycan
(B) Integral proteins
(C) Lipoteichoic acid
(D) Lipopolysaccharide
(E) Phospholipids

Hormones are chemical molecules produced by endocrine glands. one such endocrine gland is the thyroid gland, which synthesizes the thyroid hormone, which in turn affects the heart muscles. which two statements describe the probable reason for the function of the hormone? the cells in the heart have specific receptors that allow for the intake of hormones. the heart and the endocrine glands have the exact same types of cells. all cells make the same types of hormones. thyroid hormones show their effect on the heart by means of specialized cells. thyroid cells and cardiac cells have different dna.