Which of the following statements is false?
a. A heart will stop beating when the nerves to the
heart are severed.
b. Some cardiac muscle cells are self-excitatory.
c. The pacemaker of the heart is the sinoatrial
node.
d. Cardiac muscle cells have numerous gap
junctions on their sides to allow rapid
communication.
e. Cardiac muscle cells of the two ventricles
contract essentially in unison.
Answer: a
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Which of the following is NOT an autoimmune disease?
A. multiple sclerosis B. type I diabetes C. myasthenia gravis D. HIV E. All of these conditions are autoimmune diseases.
Polypeptides must be sorted after translation. Does protein sorting occur in both prokaryotes and eukaryotes? Describe the process of protein sorting and explain how the signal sequence is involved
What would you expect to see if the signal sequence has been mutated or deleted?
Which of the following is not an example of artificial selection?
A. different varieties of roses; yellow, pink, red, thornless, climbing, etc. B. different breeds of cats; Siamese, Persian, Himalayan, American shorthair, etc. C. different types of tomatoes; roma, beefsteak, grape, cherry, etc. D. different styles of potatoes; fried, mashed, baked, etc. E. different breeds of dogs; poodle, basset hound, Chihuahua, Great Dane, etc.
Which of the following is not a characteristic of a prokaryote?
A. Its DNA is not encased in a membrane. B. It has a cell wall made of peptidoglycans or other distinct chemicals. C. It does not have membrane-bound organelles. D. Its DNA is wrapped around histones. E. All of these are characteristics of prokaryotes.