Ch.9 Molecular Biology Flashcards
alternative RNA splicing
a post-transcriptional gene regulation mechanism in eukaryotes in which multiple protein products are produced by a single gene through alternative splicing combinations of the RNA transcript
codon
the consecutive nucleotides in mRNA that specify the addition of a specific amino acid or the release of a polypeptide chain during translation
deoxyribose
a five-carbon sugar molecule with.a hydrogen atom rather than a hydroxyl group in the 2’ position; the sugar component of DNA nucleotides
DNA ligase
the enzyme that catalyzes the joining of DNA fragments together
DNA polymerase
an enzyme that synthesizes a new strand of DNA complementary to a template strand
double helix
the molecular shape of DNA in which twi strand of nucleotides win around each other in a spiral shape
epigenetic
describing non-genetic regulatory factors, such as changes in modifications to histone proteins and DNA that control accessibility to genes in chromosomes
exon
a sequence present in protein-codoning mRNA after completion of pre-mRNA splicing
gene expression
processes that control whether a gene is expressed
genetic code
the amino acids that correspond to three-nucleotide codons of mRNA
helicase
an enzyme that helps ton open up the DNA helix during DNA replication by breaking the hydrogen bonds
intron
non-protein condoning intervening sequences that are spliced fro mRNA during processing
lagging strand
during replication of the 3’ and 5’ strand, the strand that is replicated in short fragments and away form the replication fork
mismatch repair
a form of DNA repair in which non-complentary nucleotides are recognized,excised, and replaced with correct nucleotides
mRNA
messenger RNA; a form of RNA that carries the nucleotides sequence code for a protein sequence that is translated into a polypeptide sequence
mutation
a permanent variation in the nucleotides sequence of a genome
nitrogenous base
a nitrogen containing molécule that acts as a base; often referring to one of the purine of pyrimidine components of nucleic acid
nontemplate strand
the strand of DNA that is not used to transcribe mRN; this strand is identical to the mRNA except that T nucleotides in the DNA are replaced by U nucleotides in the mRNA
nucleotide excision repair
a form of DNA repair in which the DNA molecule is unwound and separated in the region of the nucleotide dance, the damage nucleotides are removed and replaced with new nucleotides using the complementary strand, and the DNA is resealed and allowed to rejoin its complement
Okarzaki fragments
the DNA fragments that are synthesized in short stretches on the lagging strand
phosphate group
a molecular group consisting of a central phosphorus atom bound to four oxygen atoms
post-transcriptional
control of gene expression after the RNA molecule has been created but before it is translated into protein
post-translation
control of gene expression after a protein has been created
primer
a short stretch of RNA nucleotides that is required to initiate replication and allow DNA polymerase to bind and begin replication
promoter
a sequence on DNA to which RNA polymerase and associated factors bing and initiate transcription
replication fork
the Y- shaped structure formed during the initiation of replication
RNA polymerase
an enzyme that synthesizes an RNA strand from a DNA template strand
rRNA
ribosomal RNA; molecules of RNA that combine storage form part of ribosome
semiconservative replication
the method used to replicate DNA I which the double stranded molecule is separated and each strand acts as a template for a new strand to the synthesized, so the resulting DNA molecule are composed of one new strand of nucleotides and one old strand of nucleotides
splicing
the process of removing introns and reconnecting eons in a pre-mRNA
start codon
the AUG(or rarely GUG) on a mRNA from which translation beings; always specifies methionine
stop codon
one of the three mRNA codons the specifics termination of translation
telomerase
an enzyme that contains a catalytic part and an inbuilt
RNA template; it functions to maintain telomeres at chromosome ends
template strand
the strand of DNA that specifies the complementary mRNA molecule
transcription bubble
the region of locally unwound DNA that allows for transcription of mRNA
tRNA
transfer RNA; an RNA molecule that contains a specific three- nucleotide anticodon sequenced to pair with the mRNA condon and also binds to a septic amino acid
telomere
the DNA at the end of linear chromosomes
