Danish scientist Hans Christian Gram devised a method to differentiate two types of bacteria based on the structural differences in their cell walls. In his test, bacteria that retain the crystal violet dye do so because of a thick layer of peptidoglycan and are called Gram-positive bacteria. In contrast, Gram-negative bacteria do not retain the violet dye and are colored red or pink. Compared with Gram-positive bacteria, Gram-negative bacteria are more resistant against antibodies because of their impenetrable cell wall. These bacteria have a wide variety of applications ranging from medical treatment to industrial use and Swiss cheese production.
Answer:
A.) Smell is a chemical sense.
B.) Odorant molecules dissolve in mucus before stimulating a receptor
C.) Olfactory receptors have hairs on the apical surface that respond to stimuli
<span>Antibiotics work by selectively targeting the reproduction or growth of specific bacteria cells and by not attacking human DNA. Antibiotics do not, or should not, target and affect human DNA gyrases, although they should target the specific bacteria growth. The host, (human) DNA needs to remain unharmed while the bacteria does not replicate.</span>