3.1.5 Nucleic Acids Flashcards

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1
Q

Describe how a phosphodiester bond is formed between two nucleotides within a DNA molecule

A

+ condensation reaction
between phosphate an
deoxyribose
+ catalysed by DNA polymerase

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2
Q

Describe how the separation of strands occurs

A

+ DNA helicase breaks hydrogen
bonds between base pairs/
polynucleotide chains

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3
Q

Describe the role of DNA polymerase in the semi-conservative replication of DNA

A

+ joins adjacent DNA nucleotides
+ catalyses condensation
reactions
+ catalyses formation of phosphodiester

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4
Q

What is the role of the single-stranded DNA fragments

A

+ template
+ determines the order nucleotides/bases

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5
Q

What is the role of DNA nucleotides

A

+ forms complementary pairs

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6
Q

Contrast the structures of ATP and a nucleotide found in DNA

A
  1. ATP has ribose and DNA nucleotide has deoxyribose
  2. ATP has 3 phosphate groups and DNA nucleotide has 1 phosphate group
  3. ATP - base always adenine and in DNA nucleotide base can vary
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7
Q

Explain why the enzymes work in opposite directions

A

+ DNA has anti parallel strands
+ Shape of the nucleotides is different/aligned differently
+ Enzymes have active sites with specific shape
+ Only binds to substrates with complementary shape

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8
Q

Explain why nucleotides can only be added in a 5’ to 3’ direction

A

+ DNA polymerase joins nucleotides
+ It is specific
+ Only complementary with 5’ end of strand
+ Strands of 5’ end and 3’ end are different

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