Complete List of Terms and Definitions for The Molecular of Inheritance 6

Terms Definitions
nuclease DNA-cutting enzyme
Bacteriophage A virus that infects bacteria.
Heterochromatin Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed
Lagging Strand A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5' to 3' direction away from the replication fork
uracil a nitrogen-containing base found in RNA (but not in DNA) and derived from pyrimidine
DNA This is a polymer of nucleotides.
topoisomerase A protein that breaks, swivels, and rejoins DNA strands. During DNA replication, topoisomerase helps to relieve strain in the double helix ahead of the replication fork.
Helicase An enzyme that untwists the double helix at the replication forks, separating the two parental strands and making them available as template strands
Leading Strand The new complementary DNA strand synthesized continuously along the template strand toward the replication fork in the mandatory 5' to 3' direction
DNA ligase An enzyme that joins the sugar-phosphate backbones of all the Okazaki fragments into a continuous DNA strand
ribonucleic acid (biochemistry) a long linear polymer of nucleotides found in the nucleus but mainly in the cytoplasm of a cell where it is associated with microsomes
Mismatch repair enzymes remove and replace incorrectly paired nucleotides that have resulted from replication errors
Primerase An enzyme that joins RNA nucleotides to make the primer using the parental DNA strand as a template
Conservative model The parental double helix reamins intact and an all-new copy is made.
Origins of replication Special sites where the replications of a DNA molecule begins
Double Helix A pair of parallel helices intertwined about a common axis
Telomere The tandemly repetitive DNA at the end of a eukaryotic chromosome's DNA molecule that protects the organism's genes from being eroded during successive rounds of replication.
Hershey and Chase (1952) Carried out experiments that lent strong support to the theory that DNA is the genetic material. Tagged bacteriophages with different radioactive isotopes in the DNA once and in the proteins once. Only the DNA radioactivity transferred to the preceding generation.
primer A polynucleotide with a free 3´ end, bound by complementary base pairing to the template strand, that is elongated during DNA replication.
antiparallel two strands of DNA are oriented in opposite directions
What is a change in genotype and phenotype due to the assimilation of external DNA by a cell? Transformation
Which direction do DNA strands elongate 5' -> 3'
okazaki fragments Short fragments of DNA that are a result of the synthesis of the lagging strand during DNA replication.
base pairing principle that bonds in DNA can form only between adenine and thymine and between guanine and cytosine
What are Okazaki Fragments? Okazaki Fragments are lagging strands synthesized as a series of segments.
single-strand binding protein A protein that binds to the unpaired DNA strands during DNA replication, stabilizing them and holding them apart while they serve as templates for the synthesis of complementary strands of DNA.
Single Strand Binding Proteins Proteins that bind to and stabilize the signle strands of DNA exposed when helicase unwinds the double helix in preparation for replication.
Watson and Crick built the first model of the double helix
What function does Ligase perform in DNA replication? Joins newly synthesized DNA
Single Strand Binding Protein A protein that binds to the unpaired DNA strands during DNA replication, stabilizing them and holding them apart while they serve as templates for the synthesis of complementary strands of DNA.
In which order are enzymes used in DNA replication? 1. Helicase2. Primase3. DNA Polymerase4. Ligase
What function does Primase perform in DNA replication? Tells the DNA where to start to make a RNA primer to start a new chain.