Chapter 14: DNA The Genetic Material Flashcards
DNA
Deoxyribonucleic acid. A molecule that encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses. Contains 5-carbon sugar, phosphate group, and nitrogen-containing base (purine or pyrimadine)
pyrimidine
Produces RNA and DNA, proteins and starches, the regulation of enzymes and cell signaling.
purine
Produces of RNA and DNA, proteins and starches, the regulation of enzymes and cell signaling.
thymine dimer
UV light causes a covalent bond to form between adjacent thymine bases on the same strand, in the next round of replication will often cause incorrect base to be substituted in the new strand
thymine
a pyrimidine base, C 5 H 6 N 2 O 2, that is one of the principal components of DNA, in which it is paired with adenine.
base-pair
Two chemical bases bonded to one another forming a “rung of the DNA ladder.” The DNA molecule consists of two strands that wind around each other like a twisted ladder. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.
origins of replication
A particular sequence in a genome at which replication is initiated. This can either involve the replication of DNA in living organisms such as prokaryotes and eukaryotes, or that of DNA or RNA in viruses, such as double-stranded RNA viruses.
topoisomerase
Enzyme that cuts and rejoins helix to prevent tangling.
DNA ligase
An enzyme that eventually joins the sugar-phosphate backbones of the Okazaki fragments.
replisome
Macromolecular assembly formed by enzymes involved in DNA replication; two main subcomponents: primosome (primase and helicase) and a complex of DNA Pol III enzymes.
phosphate group
A functional group or radical comprised of phosphorus attached to four oxygen, and with a net negative charge, thus represented as PO4.
adenine
One of the two purine nucleobases (the other being guanine) used in forming nucleotides of the nucleic acids. In DNA, adenine binds to thymine via two hydrogen bonds to assist in stabilizing the nucleic acid structures. In RNA, which is used for protein synthesis, adenine binds to uracil.
uracil genetics
One of four chemical bases that are part of RNA. The other three bases are adenine (A), cytosine (C), and guanine (G). In DNA, the base thymine (T) is used in place of uracil.
antiparallel
A single strand of DNA has an inherent polarity. 5’ and 3’ ends.
DNA pol I
Acts on the lagging strand to remove primers and replace them with DNA
DNA pol III
Main replication enzyme; it is responsible for the bulk of DNA synthesis
primase
An enzyme involved in the replication of DNA. DNA primase is a type of RNA polymerase which creates a RNA primer (later this RNA piece is removed by a 5’ to 3’ exonuclease); next, DNA polymerase uses the RNA primer to replicate ssDNA.
leading strand
Strand of DNA that is synthesized continuously.
telomeres
Structures at the ends of eukaryotic chromosomes protecting the ends of chromosomes from nucleases and maintain the integrity of linear chromosomes; composed of specific DNA sequences.
nitrogenous base
Main function of a nitrogenous base is to bond nucleic acids together. A nitrogenous, or nitrogen-containing, base is an organic molecule with a nitrogen atom that has the chemical properties of a base. A nitrogenous base owes its basic properties to the lone pair of electrons of a nitrogen atom.
guanine
One of the four main nucleobases found in the nucleic acids DNA and RNA, the others being adenine, cytosine, and thymine.
phosphodiester bond
The type of bond that links the nucleotides in DNA or RNA. joins the phosphate group of one nucleotide to the hydroxyl group on the sugar of another nucleotide.
semiconservative model
Model of DNA replication. When a doule helix replicates, each of two daughter molecules will have one old and one new strand.
DNA gyrase
Topoisomerase involved in DNA replication.
