Cell Biology - Chapter 6 Vocab

Template

A molecular structure that serves as a pattern for the production of other molecules

Replication Origin

Nucleotide sequence at which DNA replication is initiated

Replication Fork

Y-shaped DNA junction at the site where DNA is being replicated

DNA Polymerase

Enzyme that catalyzes the synthesis of a DNA molecule from a DNA template using deoxyribonucleoside triphosphate precursors

Okazaki Fragment

Short length of DNA, including an RNA primer, produced on the lagging strand during DNA replication. Following primer removal, adjacent fragments are rapidly joined together by DNA ligase to form a continuous DNA strand

Lagging Strand

At a replication fork, the DNA strand that is made discontinuously in short fragments that are later joined together to form one continuous new strand

Leading Strand

At a replication fork, the DNA strand that is made by continuous synthesis in the 5′-to-3′ direction

Proofreading

The process by which DNA polymerase corrects its own errors as it moves along DNA

Primase

An RNA polymerase that uses DNA as a template to produce a short RNA fragment that serves as a primer for DNA synthesis

DNA Ligase

Enzyme that seals nicks that arise in the phosphodiester backbone of a DNA molecule; in the laboratory, can be used to join together two DNA fragments

DNA Helicase

Enzyme that pries open the DNA double helix, using energy derived from ATP hydrolysis. Used to expose DNA single strands for DNA replication

Telomere

Repetitive nucleotide sequence that caps the ends of linear chromosomes. Counteracts the tendency of the chromosome otherwise to shorten with each round of replication

Telomerase

Enzyme that elongates telomeres, synthesizing the repetitive nucleotide sequences found at the ends of eukaryotic chromosomes

RNA

Molecule produced by the transcription of DNA; usually single-stranded, it is a polynucleotide composed of covalently linked ribonucleotide subunits. Serves a variety of informational, structural, catalytic, and regulatory functions in cells

DNA Repair

Collective term for the many different enzymatic processes that correct damage to DNA

Mismatch Repair

Mechanism for recognizing and correcting incorrectly paired nucleotides—those that are noncomplementary

Nonhomologous End Joining

An error-prone mechanism for repairing double-strand breaks in DNA by rejoining the two broken ends; often results in a loss of information at the site of repair

Homologous Recombination

Mechanism by which double-strand breaks in a DNA molecule can be repaired flawlessly; uses an undamaged, duplicated, or homologous chromosome to guide the repair. During meiosis, the mechanism results in an exchange of genetic information between the maternal and paternal homologs

Mutation

A randomly produced, permanent change in the nucleotide sequence of DNA

Cancer

Disease caused by abnormal and uncontrolled cell proliferation, followed by invasion and colonization of body sites normally reserved for other cells