In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand.

Question

cytosine ... thymine
guanine ... adenine
uracil ... cytosine
thymine ... cytosine
cytosine ... uracil
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Part B
After DNA replication is completed, _____.

each new DNA double helix consists of one old DNA strand and one new DNA strand
there are four double helices
one DNA double helix consists of two old strands and one DNA double helix consists of two new strands
each of the four DNA strands consists of some old strand parts and some new strand parts
each new DNA double helix consists of two new strands
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Part C
The first step in the replication of DNA is catalyzed by _____.

single-strand binding protein
DNA polymerase
primase
ligase
helicase
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Part D
The action of helicase creates _____.

primers and replication bubbles
replication forks and replication bubbles
primers and DNA fragments
DNA fragments and replication bubbles
DNA fragments and replication forks
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Part E
Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments?

only short DNA sequences can extend off the RNA primers
it is more efficient than assembling complete new strands
DNA polymerase can assemble DNA only in the 5' to 3' direction
DNA polymerase can assemble DNA only in the 3' to 5' direction
the replication forks block the formation of longer strands
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Part F
The synthesis of a new strand begins with the synthesis of a(n) _____.

Okazaki fragment
short pieces of DNA
RNA primer complementary to a preexisting DNA strand
poly(A) tail
single-strand binding protein
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Part G
An old DNA strand is used as a _____ for the assembly of a new DNA strand.

source of nucleotides
primer
model
complement
template

Answer 1

Here are the answers for each part of your questions:

Part A: In a DNA double helix, an adenine of one strand always pairs with a(n) thymine of the complementary strand, and a guanine of one strand always pairs with a(n) cytosine of the complementary strand.

Part B: After DNA replication is completed, each new DNA double helix consists of one old DNA strand and one new DNA strand.

Part C: The first step in the replication of DNA is catalyzed by helicase.

Part D: The action of helicase creates replication forks and replication bubbles.

Part E: The new DNA strand complementary to the 3' to 5' strand is assembled in short segments because DNA polymerase can assemble DNA only in the 5' to 3' direction.

Part F: The synthesis of a new strand begins with the synthesis of a(n) RNA primer complementary to a preexisting DNA strand.

Part G: An old DNA strand is used as a template for the assembly of a new DNA strand.