Facilitated diffusion is an important method for cells in obtaining necessary molecules and removing other ones. Requirements for facilitated diffusion include
A. The carrier molecule is nonspecific to the molecule that is transported. The direction of movement is always against the concentration gradient, never with the gradient.
B. The carrier molecule must be specific to the molecule that is transported and an ATP molecule must be attached to the specific carrier. The direction of movement is always against the concentration gradient, never with the gradient.
C. The carrier molecule is nonspecific to the molecule that is transported. The direction of movement is always with the concentration gradient, never against the gradient.
D. The carrier molecule must be specific to the molecule that is transported. The direction of movement is always with the concentration gradient, never against the gradient.
Answer: D
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a. B. cereus b. B. subtilis c. B. thuringiensis d. B. anthracis
Which would be more likely to cause illness-a water sample that tested positive for coliforms or one that tested positive for E. coli O157:H7?
A. Both would be equally capable of causing illness-all coliforms cause illness. B. The coliform positive sample would be more likely to cause illness. Coliforms are inherently more pathogenic than the weak O157:H7 lab strain of E. coli. C. The E. coli O157:H7 sample would be more likely to cause illness. This strain of bacterium is highly pathogenic and capable of causing kidney damage. D. Neither-there is usually a small amount of coliforms (including E. coli O157:H7) in all water.
Nonpolar signaling molecules enter the cell by ____
a. facilitated diffusion b. simple diffusion c. osmosis d. active transport e. receptor-mediated endocytosis
Pepsin digests
A. carbohydrates. B. proteins. C. nucleic acids. D. fats.