Chapter 2 Flashcards
bacteriophage
a virus that infects bacterial cells
FISH
detect specific DNA sequences on a chromosome, uses fluorescent dye
DNA
a nucleic acid composed of deoxyribonucleotides that carries the genetic information of a cell
DNA molecule
generally refers to a double strand of DNA
nucleotide
a molecule consisting of a five carbon sugar, phosphate, and nitrogen bases, DNA is a polymer of nucleotides containing deoxyribose
phosphodiester bond
the covalent bond that connects two nucleotides in the backbone of DNA
nucleic acid
a polymer composed of nucleotide monomers
phosphodiester bond
chemical linkage between adjacent nucleotide residues in DNA
complementary base pairing
association between specific nitrogenous bases of nucleic acids stabilized by hydrogen bonding, A with T and G with C
antiparallel
the opposite orientation of the strands in a DNA double helix with one strand running 5 to 3 and 3 to 5
double helix
secondary structure of DNA, consisting of two antiparallel DNA strands wound around each other
chromatid
one half of two identical copies of a replicated chromosome
sister chromatids
the identical chromatids of a recently replicated chromosome, connected at the centromere until separated at anaphase
centromere
constricted region of a replicated chromosome where the two sister chromatids join until anaphase
telomere
region of repetitive DNA sequences at the end of a chromosome, protect the ends, become slightly shorter after cell divides
nucleosome
a section of DNA that is wrapped around a core of histone proteins
histone
basic protein that act as spools around which DNA winds to create structural units called nucleosomes
chromatin
a mixture of DNA and proteins that form the chromosomes found in Eukaryotic cells
Euchromatin
more lightly packed chromatin that is more accessible for gene transcription
Heterochromatin
tightly packed chromatin that is less accessible for transcription
template strand
single strand of DNA used by DNA polymerase to synthesize a new strand
semiconservative replication
the mechanism of replication used by cells to copy DNA, results: each daughter DNA molecule containing one old and one new
semi-discontinuous replication
in replication one is replicated continuously and one is discon. in fragments
bidirectional replication
refers to the replication of DNA in both directions from origins of replication
origin of replication
site on the chromosome at which DNA replication begins
replication bubble
where a double stranded molecule of DNA is separated into two single strands for bidirectional replication
3’ end
an end of DNA with a free OH group attached to the 3’ carbon of the deoxyribose sugar
5’ end
an end of DNA with a free phosphate group attached to the 5’ carbon of sugar
leading strand
a single DNA strand that during DNA replication is replicated continuously in same direction as replication fork
lagging strand
during DNA replication, its discontinuous and in the opposite direction of fork
RNA primer
short segment of a single stranded RNA used as a binding site for DNA polymerase to initiate replication
Okazaki fragment
short sections of DNA formed at the time of discontinuous synthesis of the lagging strand during replication
primase
an enzyme that synthesizes RNA primers during DNA replication
helicase
an enzyme that separates double stranded DNA into single strands allowing each strand to be copied
topoisomerase
enzymes that catalyze changes in the topological state of DNA
DNA ligase
a specific type of enzyme that facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond between nucleotides
single stranded DNA binding proteins
proteins that bind with high affinity to single stranded DNA to stabilize single strands during DNA replication
sliding clamp
a ring shaped protein that encircles duplex DNA, binds to DNA polymerase and tethers it to the DNA template
Telomerase
a reverse transcriptase that adds a species dependent telomere repeat sequence to the 3’ end of telomeres
