AP BIO 6-1 vocab terms unit 6: Gene expression and regulation

Phage

A virus that infects bacteria; also called a bacteriophage.

Restriction site

A specific sequence on a DNA strand that is recognized and cut by a restriction enzyme.

Nucleic Acid Hybridization

The process of base pairing between a gene and a complementary on another nucleic acid molecule.

Lagging Strand

A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5'S 3' direction away from the replication fork.

Transformation

(1) The process by which a cell in culture acquires the ability to divide indefinitely, similar to the division of cancer cells. (2) A change in genotype and phenotype due to the assimilation of external DNA by a cell. When the external DNA is from a member of a different species, transformation results in horizontal gene transfer.

Anti parallel

Referring to the arrangement of the sugar-phosphate backbones in a DNA double helix (they run in opposite 5' S 3' directions).

Genetic engineering

The direct manipulation of genes for practical purposes.

DNA replication

The process by which a DNA molecule is copied; also called DNA synthesis.

Double helix

The form of native DNA, referring to its two adjacent antiparallel polynucleotide strands wound around an imaginary axis into a spiral shape.

CRISPR-Cas9 system

A technique for editing genes in living cells, involving a bacterial protein called Cas' associated with a guide RNA complementary to a gene sequence of interest.

Plasmids

A small, circular, double-stranded DNA molecule that carries accessory genes separate from those of a bacterial chromosome; in DNA cloning, can be used as a vector carrying up to about 10,000 base pairs (10 kb) of DNA.

Nucleotide excision repair

A repair system that removes and then correctly replaces a damaged segment of DNA using the undamaged strand as a guide.

Sticky end

A single-stranded end of a double-stranded restriction fragment.

Primer

A short polynucleotide with a free 3' end, bound by complementary base pairing to the template strand and elongated with DNA nucleotides during DNA replication.

Semiconservative model

Type of DNA replication in which the replicated double helix consists of one old strand, derived from the parental molecule, and one newly made strand.

DNA cloning

The production of multiple copies of a specific DNA segment.

Virus

An infectious particle incapable of replicating outside of a cell, consisting of an RNA or DNA genome surrounded by a protein coat (capsid) and, for some viruses, a membranous envelope.

Nuclease

An enzyme that cuts DNA or RNA, either removing one or a few bases or hydrolyzing the DNA or RNA completely into its component nucleotides.

DNA polymerases

An enzyme that catalyzes the elongation of new DNA (for example, at a replication fork) by the addition of nucleotides to the 3' end of an existing chain. There are several different DNA polymerases; DNA polymerase Ill and DNA polymerase I play major roles in DNA replication in E. coli.

Replication fork

A Y-shaped region on a replicating DNA molecule where the parental strands are being unwound and new strands are being synthesized.

Operator

In bacterial and phage DNA, a sequence of nucleotides near the start of an operon to which an active repressor can attach. The binding of the repressor prevents RNA polymerase from attaching to the promoter and transcribing the genes of the operon.