CH 10-11 DNA Structure and Replication

These flashcards cover key vocabulary and concepts related to DNA structure, replication, and genetic recombination, useful for exam preparation.

DNA

Molecule that stores genetic information in its sequence of bases.

RNA

Ribonucleic acid that plays roles in coding, decoding, regulation, and expression of genes.

Semiconservative replication

Model of DNA replication where each strand serves as a template for a new strand.

DNA helicase

Enzyme that unwinds the DNA double helix by breaking hydrogen bonds between bases.

DNA polymerase

Enzyme that synthesizes new DNA strands by adding nucleotides to an existing strand.

dNTP

Deoxyribonucleoside triphosphate, the building blocks of DNA.

Primase

Type of RNA polymerase that synthesizes a short RNA primer to initiate DNA replication.

Leading strand

Strand of DNA synthesized continuously towards the replication fork.

Lagging strand

Strand of DNA synthesized discontinuously away from the replication fork in Okazaki fragments.

Okazaki fragments

Short segments of DNA synthesized on the lagging strand during DNA replication.

Single-strand binding proteins (SSB)

Proteins that bind to and stabilize single-stranded DNA during replication.

Topoisomerases

Enzymes that relieve torsional strain ahead of the replication fork.

DNA ligase

Enzyme that seals nicks in the DNA backbone after replication.

Mismatch repair

Process in which enzymes correct errors that occur during DNA replication.

Gene conversion

Process where one allele is converted into another due to DNA repair mechanisms.

Recombination

Mechanism that allows genetic material to be rearranged and exchanged during meiosis.

Heteroduplex

Region of DNA formed by strands from two different sources that can contain mismatches.

Crossover

Exchange of genetic material between homologous chromosomes during meiosis.

Exonuclease

Enzyme that removes nucleotides from the ends of DNA strands.

Dmc1

Recombination enzyme that facilitates strand invasion during homologous recombination.

Spo11

Protein that initiates recombination by forming double-strand breaks in DNA.

DNA synthesis accuracy

Process ensured by redundancy and proofreading mechanisms in DNA polymerases.

Bidirectional replication

DNA replication that proceeds in two directions from a single origin of replication.

Branch migration

Movement of the crossover point during recombination, lengthening heteroduplex regions.

Holliday junction

Intermediate structure formed during homologous recombination where two DNA strands are intertwined.

Resolution of Holliday junction

Process of cutting and separating the strands at the Holliday junction during recombination.

Mismatches in heteroduplexes

Pairs of non-complementary bases in DNA that can result from recombination.

Anticrossover helicase

Enzyme that prevents Holliday junction formation by disentangling invading strands.

Replication fork

The Y-shaped region where the DNA double helix is unwound during replication.

Initiator protein

Protein that binds to the origin of replication and recruits DNA helicase.

Replication bubble

Region of single-stranded DNA formed during replication where the double helix is unwound.

Template strand

Strand of DNA that serves as a guide for the synthesis of a complementary strand.

Nondisjunction

Failure of homologous chromosomes to separate properly during meiosis, leading to uneven distribution.

Covalent bonds in DNA

Type of strong link between nucleotides in the DNA strand, specifically in the sugar-phosphate backbone.