Unformatted text preview: 17. Mo was the first person to describe living single cells?
A) Leeuwenhoek D)Sl .
EWirchm 18. Which of the following is a®ot the Cell Theory? 1) All organisms are composed of one or re cells. / 2) The cell is the structural unit of life. ‘ 3) Cells can arise only by division from a preexisting cell.vi‘/
4) Cells divide only by fission. A)1
C)3 D)4 ‘EN,2and3 19. What is the name of the enzyme that cleaves QSRNA into the small, double—
stranded fra ment wn as small—‘ 9 rin RNAs siRNAs)?
B C) deoxyribonuclease
D) RNA helicase
E) reverse transcriptase 20. H bonds individually are verymwe‘ak and yet the strands of a DNA double W.” helix canWébparated only by very high temperatures
approaching 100°C. How does the weakness of H bonds account for
such a strong interaction? (/ A) H bond strength decreases with the distance it covers 0/ Blgl bond strength increases with the distance it covers. W bond strength is additive and the many H bonds holding the strands
together make it stable. ,. »
D) Four H bonds is enough to enhance the strength of the interactions of the two
fTHboud strength is proportional to the molecular weights of the interacting
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- Fall '09
- cell biology