9 Dna stuff Flashcards
(31 cards)
deoxyribose
a 5-carbon sugar molecule component of DNA nucleotides
phosphate group
a molecular group consisting of a central phosphorus atom bound to four oxygen atoms
nitrogenous base
a nitrogen-containing molecule that acts as a base, component of DNA
DNA polymerase
an enzyme that synthesizes a new strand of DNA complementary to a template strand
semiconservative replication
the method used to replicate DNA in which the double-stranded molecule is separated and each strand acts as a template for a new strand to be synthesized, so the resulting DNA molecules are composed of one new strand of nucleotides and one old strand of nucleotides
lagging strand
during replication of the 3’ to 5’ strand, the strand that is replicated in short fragments and away from the replication fork
replication forks
the Y-shaped structure formed during the initiation of replication
mismatch repair mechanism
a form of DNA repair in which non-complementary nucleotides are recognized, excised, and replaced with corrre
primer
a short stretch of RNA nucleotides that is required to initiate replication and allow DNA polymerase to bind and begin replication
codon
three consecutive nucleotides in mRNA that specify the addition of a specific amino acid or the release of a polypeptide chain during translation
Okazaki fragments
the DNA fragments that are synthesized in short stretches on the lagging strand
gene expression
processes that control whether a gene is expressed
epigenetic
describing non-genetic regulatory factors, such as changes in modifications to histone proteins and DNA that control accessibility to genes in chromosomes
telomeres
the DNA at the end of linear chromosomes
telomerase
an enzyme that contains a catalytic part and an inbuilt RNA template; it functions to maintain telomeres at chromosome ends
nucleotide excision repair
a form of DNA repair in which the DNA molecule is unwound and separated in the region of the nucleotide damage, the damaged nucleotides are removed and replaced with new nucleotides using the complementary strand, and the DNA strand is resealed and allowed to rejoin its complement
mutation
a permanent variation in the nucleotide sequence of a genome
mRNA
messenger RNA; a form of RNA that carries the nucleotide sequence code for a protein sequence that is translated into a polypeptide sequence
nontemplate strand
the strand of DNA that is not used to transcribe mRNA
transcription bubble
the region of locally unwound DNA that allows for transcription of mRNA
promoter
a sequence on DNA to which RNA polymerase and associated factors bind and initiate transcription
template strand
the strand of DNA that specifies the complementary mRNA molecule
RNA polymerase
an enzyme that synthesizes and RNA strand from a DNA template strand
splicing
the process of removing introns and reconnecting exons in a pre-mRNA
