Ap Bio Vocab Unit 6

Antiparallel

the orientation of the two complementary strands of DNA double helix,one strand runs in the 5’ to 3’ direction, and opposite complementary strand runs in the 3’ to 5’ direction

Cas9

an RNA guided endonuclease enzyme that are “molecular scissors” which target and cleaves specific DNA sequences,acting as a critical tool for editing genomic DNA

Central Dogma

the fundamental theory outlining the one-directional flow of genetic information within a biological system: DNA→RNA→Protein

Codon

A three nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal

CRISPR

A technique for editing genes in living cells,involving a bacterial protein called Cas9 associated with a guide RNA complementary to a gene sequence of interest

Differentiation (of cells)

The process by which a cell or groups of cells become specialized in structure and function

DNA methylation

The presence of methyl groups on the DNA bases of plants,animals and fungi,typically acting to turn genes off without altering genetic sequence

Epigenetics

The study of the inheritance of traits transmitted by mechanisms that don’t involve the nucleotide sequence

Exon

A sequence within a primary transcript that remains in the RNA after RNA processing; also refers to the region of DNA from which this sequence was transcribed

Genome

The genetic material of an organism or virus, the complete compartment of an organisms or viruses genes along with its noncoding nucleic acid sequences

Helicase

An enzyme that untwists the double helix of DNA at replication forks, separating the two strands and making them available as template strands

Intron

A non coding intervening sequence within a primary transcript that is removed from the transcript during RNA processing

Leading Strand

The new complementary DNA strand synthesized continuously along the template strand toward the replication fork in the mandatory 5’→3’ direction

Nuclease

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

Okazaki fragment

A short segment of DNA synthesized away from the replication fork on a template strand during DNA replication. Many such segments are joined together making up the lagging strand

Operon

A unit of genetic function found in bacteria and phages,consisting of a promoter,an operator and a condetly regulated cluster of genes whose products function in a common pathway

Plasmid

A small,circular,double stranded DNA molecule that carries accessory genes separate from those of a bacterial chromosome

Polymerase

a crucial enzyme that builds new strands of DNA or RNA by linking together nucleotide building blocks,essential for replication and transcription

Proto-oncogene

A normal cellular gene that has the potential to become an oncogene

Primary transcription

An initial RNA transcription from any gene, also called pre-mRNA when transcribed from a protein coding gene

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

Promoter

A specific nucleotide sequence in the DNA of a gene that binds RNA polymerase,positioning it to start transcribing RNA at the appropriate place

Replication bubble

a locally unwound,open region of DNA where replication occurs,forming as hydrogen bonds are broken at the origin of replication

Repressor

A protein that inhibits gene transcription by binding to specific DNA sequences called operators or silencers

Restriction enzyme

an endonuclease(type of enzyme) that recognizes and cuts DNA molecules foreign to a bacteruim the enzyme cuts at restriction sites

Ribozyme

An RNA molecule that functions as an enzyme which accelerate specific biochemical reactions

Semiconservative

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

Spliceosome

A large complex made up of proteins and RNA molecules that splices RNA by interacting with the ends of an RNA intron,releasing the intron and joining the two adjacent exons

Stem Cell

Any relatively unspecialized cell that can produce,during a single division,two identical daughter cells or two more specialized daughter cells that can undergo further differentiation

Telomeres

protective,repetitive DNA protein caps at the end of linear chromosomes that prevent genetic data loss during cell division

Topoisomerase

A protein that breaks,swivels and rejoins DNA strands. During DNA replication it helps relieve strain in the double helix ahead of the replication fork

Transcription factor

A regulatory protein that binds to DNA and affects transcription of specific genes

Transformation

The specific agent, identified as DNA, that enables a cell to takes up foreign genetic material from its environment and incorporate it into its own genome