Eukaryotes probably originated about
A. four billion years ago.
B. two billion years ago.
C. four million years ago.
D. three billion years ago.
E. three million years ago.
Answer: B. two billion years ago.
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Consider the cladogram shown. Which pair of species shares the greatest number of derived characters (synapomorphies)?
A. 4 and 2
B. 5 and 4
C. 6 and 1
D. 6 and 2
E. 5 and 2
A __________ is a noncellular infectious particle with a protein coat enclosing DNA or RNA. Fill in the blank(s) with the appropriate word(s)
Which of the following is part of a DNA molecule?
A) sigma B) RNA polymerase C) transcription factor D) promoter E) activator
Place these steps of enzyme catalysis in the correct order:
1. The substrate and enzyme change shape. 2. The substrate enters the active site. 3. The enzyme reverts to its original configuration. 4. The product is expelled. A) 2, 1, 4, 3 B) 1, 3, 4, 2 C) 2, 3, 1, 4 D) 1, 2, 3, 4 E) 2, 1, 3, 4