Chapter 16 Vocabulary Flashcards
A virus that infects bacteria; also called a phage.
Bacteriophage
The complex of DNA and proteins that makes up an eukaryotic chromosome. When the cell is not dividing, this exists in its dispersed form, as a mass of very long, thin fibers that are not visible with a light microscope.
Chromatin
The sugar component of DNA nucleotides, having one fewer hydroxyl group than ribose, the sugar component of RNA nucleotides.
Deoxyribose
A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3’ end of one DNA fragment (such as an Okazaki fragment) to the 5’ end of another DNA fragment (such as a growing DNA chain).
DNA ligase
An enzyme that catalyzes the elongation of new DNA (ex; at a replication fork) by the addition of nucleotides to the 3’ end of an existing chain. There are different kinds of these, III and I play major roles in DNA replication in prokaryotes.
DNA polymerase
The form of native DNA, referring to its two adjacent anti-parallel polynucleotide strands wound around an imaginary axis into a spiral shape.
Double helix
The less condensed form of eukaryotic chromatin that is available for transcription.
Euchromatin
An enzyme that untwists the double helix of DNA at the replication forks, separating the two strands and making them available as template strands,
Helicase
Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed.
Heterochromatin
A small protein with a high proportion of positively charged amino acids that bind to the negatively charged DNA and plays a key role in chromatin structure.
Histone
A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5’ - 3’ direction away from the replication fork.
Lagging strand
The new complementary DNA strand synthesized continuously along the template strand towards the replication fork in the mandatory 5’ - 3’ direction.
Leading strand
The cellular process that uses specific enzymes to remove and replace incorrectly paired nucleotides.
Mismatch repair
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.
Nuclease
A dense region of DNA in a prokaryotic cell.
Nucleoid
The basic, bead-like unit of DNA packing in eukaryotes, consisting of a segment of DNA wound around a protein core composed of two copies of each of four types of histone.
Nucleosome
Repair system that removes and then correctly replaces a damaged segment of DNA using the undamaged strand as a guide.
Nucleotide excision repair
A short segment of DNA synthesized away from the replication fork on a template strand during DNA replication, many of which are joined together to make up the lagging strand of newly synthesized DNA.
Okazaki fragment
Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides.
Origin of Replication
An enzyme that joins RNA nucleotides to make the primer using the parental DNA strand as a template.
Primase
A short stretch of RNA with a free 3’ end, bound by complementary base pairing to the template strand that is elongated with DNA nucleotides during DNA replication.
Primer
One of two types of nitrogenous bases found in nucleotides, characterized by a six-remembered ring. (Includes Cytosine, Thymine, and Uracil)
Pyrimidine
An isotope (atomic form of chemical element) that is unstable, the nucleus decays spontaneously, giving off detectable particles and energy.
Radioactive isotope
Nucleotide sequences, usually non-coding, that are present in many copies in a eukaryotic genome. The repeated units may be short and arranged tandemly or long and dispersed in the genome.
Repetitive DNA
A Y-shaped region on a replicating DNA molecule where the parental strands are being unwound and new strands are growing.
Replication fork
Type of DNA replication in which the replicated double helix of one of old strand, derived from the old molecule, and one newly made strand.
Semiconservative model
An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells.
Telomerase
Tandemly repetitive DNA at the end of a eukaryotic chromosomes DNA molecule that protects the organisms genes from being eroded during successive rounds of replication.
Telomere
The DNA strand the provides the pattern, or template, for ordering the sequence of nucleotides in an RNA transcript.
Template strand
A protein that breaks, swivels, and rejoins DNA strands. During DNA replication, this helps to relieve strain in the double helix ahead of the replication fork.
Topoisomerase
The conversation of a normal animal cell to a cancerous cell. OR a change in genotype and phenotype due to the assimilation of external DNA by a cell.
Transformation
A technique that depends on the diffraction of an X-ray beam by the individual atoms of a crystallized molecule to study three-dimensional structure of the molecule.
X-ray crystallography
