In order for B cells to produce antibodies and cytotoxic T cells to attack infected host cells, they must first
A. be activated by interleukins, encounter an antigen, and then develop specificity toward it.
B. recognize self markers, develop specificity for the markers, and then produce clones.
C. encounter an antigen, develop specificity for that antigen, and then remember the antigen.
D. undergo maturation, encounter their specific antigen target, and then become activated through cytokines.
Answer: D
You might also like to view...
Which of the following is NOT a unifying characteristic of diplomonads and parabasalids?
A) having flagella B) lacking chloroplasts C) lacking mitochondria D) being multicellular
Which of the following represents the correct sequence of cell types through which an electrical signal would pass in a reflex arc?
A. sensory neuron ? interneuron in the CNS ? motor neuron B. motor neuron ? interneuron in the PNS ? sensory neuron C. sensory neuron ? motor neuron ? interneuron in the CNS D. motor neuron ? sensory neuron ? interneuron in the PNS E. sensory neuron ? motor neuron ? interneuron in the CNS
Why can scratching or chipping the seed coat speed up the germination of hard-coated seeds like alfalfa?
A. The mechanical stress activates hydrolytic enzymes. B. Carbon dioxide can enter the seed and stimulate photosynthesis. C. Water and oxygen can enter the seed to reach the embryo more quickly. D. Damage to the seed coat triggers the aleurone layer to release amylase. E. Bacteria or fungi can enter the seed and release growth factors.
How is alcohol classified?
A. stimulant B. psychoactive C. inhibitor D. depressant E. none of these