24 terms

DNA Structure and Replication

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DNA
A double-stranded, helical nucleic acid molecule capable of replicating and determining the inherited structure of a cell's proteins.
purine
nitrogenous base made of two rings (adenine and guanine)
pyrimidine
nitrogenous bases made of one ring (thymine and cytosine)
phosphate group
a molecule in the backbone of DNA and RNA that links adjoining bases together
helicase
An enzyme that untwists the double helix of DNA at the replication forks.
replication fork
a Y-shaped point that results when the two strands of a DNA double helix separate so that the DNA molecule can be replicated
DNA polymerase
Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule
hydrogen bonds
The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases. - weak bond
adenine
A nucleotide that binds to thymine (DNA) and uracil (RNA); it is a purine
guanine
A nitrogenous base found in both DNA and RNA; pairs only with cytosine.
cytosine
A nitrogenous base found in DNA and RNA; pairs with guanine
thymine
A nitrogenous base that pairs with adenine. Found only in DNA.
nucleotide
Monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base
nucleic acid
a long chain of smaller molecules called nucleotides; DNA and RNA
double helix
two strands of nucleotides wound about each other; structure of DNA
antiparallel
a reference to the observation that strands on DNA double helix have their nucleotides oriented in the opposite direction to one another
base pairing rules
the rules stating that cytosine pairs with guanine and adenine pairs with thymine in DNA, and that adenine pairs with uracil in RNA
cell cycle
series of events in which a cell grows, copies the DNA, prepares for division, and divides to form two daughter cells
deoxyribose sugar
sugar used in DNA to make up the "backbone"
nitrogen base
The chemicals that make up the rungs of the DNA ladder. A-T and C-G match.
covalent bond
A chemical bond that involves sharing a pair of electrons between atoms in a molecule - strong bond
DNA replication
The process in which DNA makes a duplicate copy of itself.
primase
preps the new DNA for attachment
ligase
An enzyme that connects two fragments of DNA to make a single fragment