Fertilization is characterized by
a. a sperm's fertilin proteins binding to the ovum's integrin molecules.
b. a block to polyspermy.
c. multiple sperms penetrating the ovum.
d. blastocyst formation.
e. both (a) and (b) above.
E
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The reason it is more appropriate to call an erythrocyte a "formed element" rather than a "cell" is that erythrocytes
A. are actually dead. B. lack a nucleus and organelles. C. have lots of inclusion molecules. D. are not red. E. can form a rouleau when moving through a capillary.
Through what opening does the spinal cord pass?
A. Vertebral arch B. Transverse foramen C. Central canal D. Vertebral foramen E. Intervertebral foramen
Which of the following best describes the interaction between an enzyme and its substrate?
A. Part of the enzyme temporarily binds part of the substrate molecule. B. The enzyme temporarily deactivates the substrate. C. The enzyme surrounds and completely contains the substrate. D. The substrate surrounds and completely contains the enzyme.
Syphilis is caused by
A. Treponema pallidum. B. human papillomavirus. C. herpes simplex. D. Neisseria gonorrhaeae.