Term
| State: DNA replication is semi-conservative. |
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Definition
- semi-conservative: when the double helix replicates, each of the two daughter molecules will have one old strand, derived from the parent molecule
- and one newly made strand, from free nucleotides in solution, using the parent strands as templates, and base pairing rules (A=T, G=C) to match newly synthesised strands complementary to parental strands |
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Term
Explain DNA replication including:
A. unwinding of double helix |
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Definition
| - helicase controls unwinding of coiled DNA |
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Term
Explain DNA replication including:
B. separation of strands by helicase |
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Definition
- helicase separates complementary strands of DNA, producing a replication fork
- single strand binding proteins keep the two strands of DNA separate |
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Term
Explain DNA replication including:
C. formation of complementary strands by DNA polymerase |
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Definition
| - DNA polymerase uses a single parent strand of DNA as a template, adding free nucleotides from solution to the parent/template strand according to the complementary base pairing rules (A=T, G=C) |
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Term
| Explain: significance of complementary base pairing in conservation of base sequence. |
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Definition
- DNA polymerase uses a single parent strand of DNA as a template, adding free nucleotides from solution to the parent/template strand according to the complementary base pairing rules (A=T, G=C)
- the 2 parent strands in the double helix of DNA can be represented as A and A'
- when the 2 strands separate, each acts as a template for DNA synthesis
- using strand A as a template, DNA polymerase, using complementary base pairing rules, adds a newly synthesised A' strand, thus producing A-A' double-stranded DNA identical to the parent DNA
- using strand A' as a template, DNA polymerase, using complementary base pairing rules, adds a newly synthesised A strand, thus producing A-A' double-stranded DNA identical to the parent DNA
- therefore, 2 DNA molecules, each A-A' are produced |
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