Unformatted text preview: Douglass/Cook Lectures only THE CHEMICAL BASIS OF HEREDITY
1. Evidence that DNA is the genetic material (Fig. 12-1) Describe the experiment in which Grifﬁth discovered the phenomenon of transformation.
How does a virulent strain of bacteria differ from one that is avirulent? What were his
R strain and S strain? What did Avery, MacLeod, and McCarty identify as Grifﬁth’s transforming factor (Le. the
chemical actually responsible for transformation)? How are their ﬁndings interpreted today? 112' am; ‘v’v atavu emu pubis iiiuuéi UL unn su uctuic -I, A. The double helix (Fig. 12—5) 4: B. The components of DNA and the base pairing rules (Fig 12-6)
In what pattern are bases, deoxyribose, and phosphate covalently linked in a
single DNA strand? How are the two DNA strands chemically bonded to each other? ‘ . What is the basis 0fthe base pairing rules (adenine pairs with thymine; guanine
pairs with cytosine)? .4...“ ”mm. 111. DNA replication A. Semi-conservative DNA replication (Fig. 12-10, 12-11)
Why did complementary base pairing suggest that DNA would be likely to be
synthesized by a semiconservative replication mechanism? rm l r 1‘ .. What are the roles of helicases and trjzﬂsomerases? B; Discontinuous synthesis of the lagging strand (Fig. 12-12)
Why are the two strands of a double helix said to be antiparallel? What are the consequences of the fact that DNA polymerase can only add subunits to a
growing 3' end? Why are the leading strand and the lagging strand synthesized differently? Which one
is initially synthesized as a series of Okamki fragments that are subsequently joined
together by DNA ligase? .._:J_.zamn~__u_ A. ,; ...
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- Spring '10