Palytoxin is incredibly toxic, perhaps the second most dangerous nonpeptide toxin. It targets the sodium-potassium pump, locking it open and forming a channel through which the ions can passively flow. Palytoxin is produced by zoanthid cnidarians (soft coral), and there have been incidents of poisoning from zoanthids within marine aquaria tanks in people's homes. It is also thought to be the source of the legend of the Limu make o hana ("Seaweed of Death from Hana").What is the likely impact of this toxin on action potentials?
A. They will have longer refractory periods.
B. They will occur more frequently.
C. They will be stronger and more unpredictable.
D. Without ion gradients, action potentials are not possible.
Answer: D
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Which of the following is true of the mutation
that causes cystic fibrosis?
a. it is an insertion mutation b. the protein produced is normal c. the protein produced is prevented from reaching the cell surface d. the protein produced instead of being transported into the nucleus is transported into the Golgi body e. more than one of these is true
When a person has laryngitis, he or she cannot speak. What must happen to permit normal speech?
A) Inflammation in the bronchioles has to go down before enough air can enter the lungs. B) The swelling of the vocal cords must decrease so they can vibrate normally. C) Inflammation in the trachea has to go down before enough air can enter the lungs. D) The epiglottis must cover the glottis.
The more morphological characteristics that two species of animals share, the more likely it is that they:
a) live in the same habitat. b) have evolved by genetic drift. c) have hybridized. d) have evolved by convergent evolution. e) share a common descent.
Terrestrial vertebrates and some fish evolved a form of fertilization in which the male gametes are introduced into the female reproductive tract. What is this called?
A. internal fertilization B. synchronous fertilization C. external fertilization D. asexual fertilization