In some vintage science fiction movies, space travelers find themselves on a planet orbiting a distant star in which there are curious forms of life based on silicon instead of carbon. Although the story clearly is sci-fi, there is an aura of
plausibility in the choice of silicon, an atom with 14 protons, in place of carbon as this alien life-form's central atom. The reason is that silicon:
A) has four electrons in its outermost shell.
B) is an isotope of carbon.
C) is lighter than carbon.
D) has one more proton than carbon, so is very similar to it.
E) is heavier than carbon.
Answer: A
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Refer to the figure above. What is the function of the ACC sequence at the end?
A) It attaches to an amino acid. B) It base pairs with the codon of mRNA. C) It stabilizes the tRNA-amino acid complex. D) It is the active site of this ribozyme.
Which of the following structures will self-assemble?
A) ribosomes B) nucleosomes C) translocons D) huntingtin E) all of the above
A(n) ________ consists of the interactions between all of the species in a given area. a. ecosystem b. biome c. community d. None of these choices
e. habitat
Which of the following is NOT true about
meiosis?
a. it produces eggs and sperm in all eukaryotes b. it is a nuclear division c. it halves the chromosome number d. it is not done by prokaryotes e. more than one of these is NOT true