Glossary I-O Flashcards
idiotope
epitopes present in the unique variable sequences of an immunoglobulin molecule. These may or may not coincide with the immunoglobulin’s paratope.
inducer
A substance that directly activates an activation factor or derepresses a repressor factor
initiator tRNA
a special tRNA responsible for annealing to the start codon, in the P site of the ribosome, to initiate polypeptide synthesis which a methionine (eukaryotes) or N-formyl-methionine (prokaryotes) residue
insertion
the presence of additional bases within a sequence that are not present in wild-type sequence
internal ribosome entry site
ribosomal entry site (ribosomal binding site) that is 3’ to one open reading frame, and 5’ to the open reading frame whose translation it is responsible for allowing
mainly found in prokaryotic polycistronic transcripts
intron
a non-coding sequence of DNA within a gene that must be spliced out of a primary transcript to yield a mature, translatable mRNA (see also Exon).
intron sequences do NOT appear in the translated polypeptide
isoform
unique sequence, and perhaps conformation, for a protein that may be encoded by multiple different gene copies or may be encoded from alternatively spliced transcripts
karyotype
the physical appearance of the full complement of stained chromosomes for an individual
kintechore
a specialized structure found in the centromeric region of the chromosome that is responsible for attaching to the spindle during nuclear division
knockout mutant
a mutant in which a gene had been disabled
in a diploid organism, both alleles have been disabled
L-chain
immunoglobulin light chain
locus
a site on a segment of DNA
long arm (q)
one of the two prominent segments of a chromosome; the short “p” are is the other. The arms of a given chromosome join at its centromere.
library
a collection of recombinant genes cloned into a vector
linear epitope
an epitope comprised of contiguous, continuous components of the immunogenic molecule.
In a polypeptide antigen this would refer to the amino acids
linkage
a measure of proximity between two alleles determined by recombination events
if they are not linked at all, there are on separate chromosomes. If loosely linked, there are distant to each other but on the same chromosome. The closer they are to one another, the more tightly they are linked.
linkage dysequilibrium
a very tight linkage that implies two traits always segregate together, even though they are distinct traits
lncRNA
Acronym meaning “long non-coding RNA”
maintenance methylase
an enzymatic activity responsible for maintaining the patterns of methylation on each strand of aDNA molecule after replication
meiosis
the 2 successive divisions of the replicated genomic DNA of a eukaryotic germline cell (4n), after which each of the resulting cells is haploid (1n)
7-methyl-guanosine triphosphate
the methylated form of guanosine triphosphate used to cap an mRNA molecule in most eukaryotes
microRNA (miRNA)
small RNA molecules, usually 23-25 nt in length, derived from larger precursors, and which affect the stability, transcription, or translation of other transcripts.
these serve a variety of functions within cells, and even serve as “messages” delivered remotely to other cells and tissues via the plasma
molecular biology
the biochemical study of genetic basis for phenotype
monocistronic
a form of gene organization resulting in transcription of an mRNA that contains coding sequence for a single gene or gene product
missense mutation
a mutation in which the identity of an encoded amino acid had been changed
mitosis
division of a eukaryotic somatic cell, after which the cell remains diploid
mRNA (messenger RNA)
the single-stranded, edited copy of a gene ultimately translated into protein
mRNA export
refers to the movement of spliced mRNA out of the nucleus to the cytoplasm
mRNA processing
refers to the processes of polyadenylation, spicing, and addition of a 5’ cap structure
multifactorial genetic diseases
those which require mutations of more than one gene, or particular combinations of multiple alleles, in order to produce disease.
often involving environmental influences
multigene family
a group of genes that are related by a sequence homologies; usually are also related by their functions or by the processes in which they participate
mutagen
an agent capable of causing mutations
common examples are ultraviolet light, such as in sunlight, and anthracene, a material found during cooking of fatty meats on a barbecue grill
mutation
a permanent change of the genetic material, either in a single gene or in the numbers or structures of the chromosomes
ncRNA (non-coding RNA)
RNAs which are transcribed from seemingly non-coding areas, or processed from coding RNAs in such a manner as to appear no longer capable of translation , and which serve to regulate gene expression and chromatin structure
nonsense mutation
a mutation in which an amino acid-encoding codon has been altered to a stop codon
Northern blot
the transfer of size-seperated RNA fragments to a synthetic membrane for further studies
nucleoside
a term referring to the combination of adenine, cytosine, guanin, or thymine with a ribose or 2-deoxyribose sugar moiety. A nucleoside is not phosphorylated
nucleosome
the repeated structure formed of dsDNA, octameric histones, and associated proteins in eukaryotes
nucleotide
one of the four building blocks of DNA (dATP, dGTP, dCTP, or dTTP) or RNA (ATP, CTP, GTP, or UTP) that are combined to form the nucleic acids
a nucleotide contains the base attached to a phosphorylated form of ribose or 2-deoxyribose
null mutant
an organism that lacks any functional allele for a given gene or trait
ochre mutation
one wherein a codon has been modified, resulting in the formation of a UAA stop codon
okazaki fragments
short DNA fragments formed on the lagging strand of dsDNA during replication
oligonucleotide
a short, continuous string of nucleotides. The prefix “oligo” means “several”
oncogene
a gene responsible for transformation of a cell to a cancerous phenotype.
may occur through active induction of transformation, or by failing to repress transformation
oncogenic transformation
a change in the behavioral phenotype of a cell to one lacking in normal proliferative control, and often involving invasive characteristics
open reading frame
That segment of the nucleic acid sequence that lies between two stop codons, when translated in a given reading frame.
The presence of an open reading frame is necessary to encode a polypeptide sequence (or an exon thereof), but the presence of an open reading frame is not proof that a polypeptide sequence is encoded in that sequence
operator sequence
that sequence at which a repressor binds to prevent transcription of the gene 3’ to the operator from the promoter 5’ to the operator sequence
operon
genes which are grouped together for coordinate regulation b the same regulator
origin of replication
a site at which DNA replication is initiated
there is only 1 in bacterial chromosomes, but numerous origins in eukaryotic chromosomal DNA
origin recognition complex
an organization of protein factors assembled at an origin of replication for the purpose of initiating transcription
orthologs
the “same gene”, found in two or more different organisms, derived from a common ancestral gene
modifications that are found between the species occurred during or subsequent to evolutionary divergence of the common ancestor into two different species
