What does proofreading by a DNA polymerase do?

It detects and removes a newly misincorporated nucleotide during replication, allowing the correct nucleotide to be added.

Mismatch repair corrects mismatched DNA bases that escaped replication proofreading, generally by excising a segment of the newly synthesized strand and resynthesizing it.

Nucleotide excision repair

Nucleotide excision repair removes a short DNA segment containing a bulky lesion, fills the gap using DNA polymerase and the intact template, and seals the backbone with ligase.

A covalent pyrimidine dimer, commonly involving neighboring thymines in one DNA strand.

What does DNA ligase do after gap filling or Okazaki fragment synthesis?

It seals a nick in the sugar-phosphate backbone by forming a phosphodiester linkage.

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Flashcard deck

Molecular Biology — Flashcards

Molecular Biology50 cardsBeginnerEnglish

A flashcard deck with 50 cards in molecular biology, made by Prognia.

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50 recall flashcards, using classic question-answer, term-definition, concept-explanation and cloze formats. Introductory molecular biology practice with 50 flashcards and 50 quizzes: DNA structure and chromatin packaging; semiconservative replication and replication machinery; transcription and RNA processing; genetic code and translation; gene regulation; basic DNA repair; and molecular laboratory techniques. Each item has source evidence, concept links and a learning objective. Twenty-five objectives support topic-specific recommendations. This is an initial practice set rather than complete molecular biology coverage. No national treatment decisions are tested.