The atomic number of an element is equal to the number of:
A. protons plus neutrons.
B. neutrons plus electrons.
C. neutrons only.
D. protons only.
E. protons plus electrons.
D. protons only.
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Why is it a good strategy for a microbe to adhere to a receptor that plays a critical function for a host cell?
A. It ISN'T a good strategy-host cells could shift to a backup receptor and shut down production of the main receptor, preventing infection. B. If it's a receptor the cell MUST use, it doesn't have a backup system in place to switch to-so, even though it makes it susceptible to infection, it HAS to put that target out there. This benefits the microbe. C. Microbes need to evade detection and elimination by the immune system-if they adhere to a receptor that plays a critical function, they are less likely to trigger destructive immune responses. This would be similar to using a hostage as a shield in a police-standoff situation. D. It ISN'T a good strategy-by binding to receptors, microbes will be phagocytosed by cells and destroyed within them.
DNA replication requires:
a. template DNA b. free nucleotides c. DNA polymerase d. all of these
ALL of the following are natural human defenses against disease EXCEPT
a) interferon. b) penicillin. c) skin. d) mucous membranes.
__________ immunity specifically targets billions of different antigens.
Fill in the blank(s) with the appropriate word(s).