Chapter 3

Question 1

A ___1.___ is ribose with a purine or pyrimidine linked to the 1’ carbon in a ___2.___ linkage

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Question 2

According to the ___1.___ model, cellular DNA is a ___2.___ double helix held together by hydrogen bonds between bases

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Question 3

The binding of two complementary strands of DNA into a double-stranded structure is termed ___1.___, or ___2.___

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Question 4

DNA 100 nucleotides long, we would say it is __1.__ base pairs (bp) long. A kbp (kilobase pair) is ds-DNA __2.__ nucleotides long

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Question 5

The temperature at which a solution of DNA molecules is 50 percent melted is termed the __1.__

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Question 6

Not only is DNA double stranded, but it is also ___1.___

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Question 7

The double helix is stabilized by ___1.___ interactions between the bases, which are stacked upon each other. The bases lie in a plane, ___2.___ to the length of the DNA molecule, stacked __3.__ angstroms apart from each other. The helix pattern repeats itself once every __4.__ angstroms, which is every 10 base pairs.

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Question 8

While the length of a DNA molecule may vary enormously from a few angstroms in an oligonucleotide to macroscopic lengths in a chromosome, the width is always __1.__ angstroms

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Question 9

An enzyme called ___1.___ uses the energy of ATP to twist the gigantic circular molecule. ___2.___ functions by breaking the DNA and twisting the two sides of the circle around each other. The resulting structure is a twisted circle that is composed of ___3.___ . As discussed above, the two strands are already ___4.___ , forming a helix. The twists created by ___5.___ are called ___6.___ , since they are coils of a structure that is already coiled.

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Question 10

FLOW EQUATION:

___1.___ ⇒ add base ⇒___2.___ ⇒ add three phosphates ⇒___3.___ ⇒ polymerize with loss of two phosphates ⇒ ___4.___ ⇒ continue polymerization ⇒ ___5.___ ⇒ two complete chains H-bonded in antiparallel orientation ⇒ ___6.___ ⇒ coiling occurs ⇒ ___7.___ ⇒ wrap around histones ⇒ ___8.___ ⇒ complete packaging ⇒ ___9.___

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Question 11

Often all four of the codons with the same ___1.___ nucleotides encode the same amino acid

Two or more codons coding for the same amino acid are known as ___2.___

Because it has such ___3.___ , the genetic code is said to be ___4.___

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