BIOL 1201 Chp 16 Vocab

Transformation

Change in genotype and phenotype due to assimilation of foreign DNA.

Bacteriophages (phages)

Viruses that infect bacteria.

Virus

DNA or RNA enclosed by a protective coat, often simply protein.

Double helix

The pattern of DNA; two strands intertwined in a ladder-like structure.

Antiparallel

their subunits run in opposite directions​

DNA replication

The copying of DNA.

Semiconservative model of replication

when a double helix replicates, each daughter molecule will have one old strand and one new strand ​

Origins of replication

where replication begins.

Replication fork

The Y-shaped region where parental DNA strands are being unwound.

Helicases

Enzymes that untwist the double helix at the replication forks.

Single-strand binding proteins

bind to stabilize the unwinding DNA​

Topoisomerase

relieves the strain of twisting the double helix by breakingswiveling and rejoining DNA strands​

Primer

the piece of RNA that makes the initial nucleotide chain​

Primase

synthesizes the RNA primer.

DNA Polymerase III

catalyzes the synthesis of new DNA at a replication fork.

DNA polymerase I

fixes DNA.

Leading strand

the DNA strand that is made continuously​

Lagging strand

the second strand of DNA replicated 5’-3’ but in fragments​

Okazaki fragments

Segments made on the lagging strand

DNA ligase

puts together the Okazaki fragments​

Mismatch repair

when DNA bases don’t match, repair enzymes replace theincorrectly paired nucleotides​

Nucleotide excision repair

a nuclease cuts out and replaces damagedstretches of DNA​

Telomeres

the ends of DNA molecules in eukaryotes​

Chromatin

DNA with proteins.

Histones

proteins that are responsible for the main level of DNA packing ininterphase chromatin​

Nucleosome

compound of DNA wound twice around a core of eighthistones, two each of the four main histone types​

Euchromatin

Loosely packed form of chromatin.

Heterochromatin

densely packed DNA (centromeres and telomeres)​