DNA Replication Flashcards

Flashcards about DNA Replication

What were Chargaff's two main rules regarding DNA?

Base composition varies between species, and A=T & C=G

Name three individuals (or groups) involved in discovering the double helix structure of DNA.

Maurice Wilkins and Rosalind Franklin, James Watson and Francis Crick

What is DNA replication?

DNA molecules are copied to produce two identical copies before cell division.

Describe the semiconservative model of DNA replication.

Each strand of the parent DNA serves as a template for a new strand, resulting in hybrid DNA molecules (original + new).

What are the three main ingredients for DNA replication?

Parent DNA molecule, proteins/enzymes, deoxyribonucleoside triphosphates (dNTPs)

What is the origin of replication (ori)?

Site where DNA replication begins.

What is a major difference regarding origins of replication between prokaryotes and eukaryotes?

Prokaryotes have circular genomes with one origin of replication; eukaryotes have linear chromosomes with multiple origins.

What is the role of DNA Polymerase III?

Catalyzes condensation reactions to join nucleotides, synthesizing new strands in the 5’ to 3’ direction.

Name four enzymes and proteins involved in the initation of DNA replication.

Helicase, single-strand DNA binding proteins, DNA primase, topoisomerase

What is the function of helicase?

Separates the two DNA strands apart (unwinds the DNA helix).

What is the function of single-strand DNA binding proteins?

Hold the two parent strands apart during replication.

What is the function of DNA primase?

Synthesizes RNA primer sequences to initiate DNA synthesis.

What is the function of topoisomerase?

Cuts and swivels DNA to relieve coiling tension (relaxes positive supercoils).

What is a replication fork?

Y-shaped region where DNA is unwound during replication.

In what direction does DNA synthesis occur?

DNA synthesis only occurs in the 5’ to 3’ direction.

What is the leading strand?

Elongates new DNA strand towards the replication fork.

What is the lagging strand?

Elongates away from the replication fork, forming Okazaki fragments.

What is the function of DNA polymerase I?

Removes RNA primers and replaces them with new DNA.

What is the function of DNA ligase?

Forms covalent bonds between DNA fragments to make the new DNA strand continuous.