You are examining a human pedigree for a trait. You notice that an offspring can be affected even if neither parent is affected. This immediately tells you that the trait is:
A. dominant.
B. recessive.
C. epistatic.
D. produced by multiple alleles.
E. incomplete penetrance.
B
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What procedure is used after PCR is done to make sure the amplification process worked properly?
A. gel electrophoresis B. Sanger sequencing C. microarray D. DNA Southern blot E. RNA interference
At which of the following time points in an action potential is a positive feedback process occurring in a neuron?
A. When the neuron is at rest. B. As the neuron is being depolarized and passes the threshold potential. C. After the peak depolarization of the action potential when it is rapidly repolarizing. D. During the undershoot phase when the neuron is slightly hyperpolarized relative to the resting potential. E. A positive feedback process is occurring at all the time points given.
Which of the following is the correct sequence of events in cross-bridge cycling?
A. Myosin cross-bridge binds to actin, the powerstroke moves the thin filament relative to the thick filament, ATP binds to myosin and cross-bridge detachment occurs, ATP is hydrolyzed and the myosin head is "cocked." B. The powerstroke moves the thin filament relative to the thick filament, myosin cross-bridge binds to actin, ATP binds to myosin and cross-bridge detachment occurs, ATP is hydrolyzed and the myosin head is "cocked." C. Myosin cross-bridge binds to actin, ATP is hydrolyzed and the myosin head is "cocked," the powerstroke moves the thin filament relative to the thick filament, ATP binds to myosin and cross-bridge detachment occurs. D. Myosin cross-bridge binds to actin, ATP binds to myosin and cross-bridge detachment occurs, the powerstroke moves the thin filament relative to the thick filament, ATP is hydrolyzed and the myosin head is "cocked." E. These events can occur in any sequence without affecting muscle function.
A chemical that does a great deal of biological damage to DNA is:
a) hydroxy ion b) hydrogen ion c) antioxidants d) hydroperoxyl radical