Glossary I-O

Question 1

idiotope

Answer 1

epitopes present in the unique variable sequences of an immunoglobulin molecule. These may or may not coincide with the immunoglobulin’s paratope.

Question 2

inducer

Answer 2

A substance that directly activates an activation factor or derepresses a repressor factor

Question 3

initiator tRNA

Answer 3

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

Question 4

insertion

Answer 4

the presence of additional bases within a sequence that are not present in wild-type sequence

Question 5

internal ribosome entry site

Answer 5

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

Question 6

intron

Answer 6

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

Question 7

isoform

Answer 7

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

Question 8

karyotype

Answer 8

the physical appearance of the full complement of stained chromosomes for an individual

Question 9

kintechore

Answer 9

a specialized structure found in the centromeric region of the chromosome that is responsible for attaching to the spindle during nuclear division

Question 10

knockout mutant

Answer 10

a mutant in which a gene had been disabled

in a diploid organism, both alleles have been disabled

Question 11

L-chain

Answer 11

immunoglobulin light chain

Question 12

locus

Answer 12

a site on a segment of DNA

Question 13

long arm (q)

Answer 13

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.

Question 14

library

Answer 14

a collection of recombinant genes cloned into a vector

Question 15

linear epitope

Answer 15

an epitope comprised of contiguous, continuous components of the immunogenic molecule.

In a polypeptide antigen this would refer to the amino acids

Question 16

linkage

Answer 16

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.

Question 17

linkage dysequilibrium

Answer 17

a very tight linkage that implies two traits always segregate together, even though they are distinct traits

Question 18

lncRNA

Answer 18

Acronym meaning “long non-coding RNA”

Question 19

maintenance methylase

Answer 19

an enzymatic activity responsible for maintaining the patterns of methylation on each strand of aDNA molecule after replication

Question 20

meiosis

Answer 20

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)

Question 21

7-methyl-guanosine triphosphate

Answer 21

the methylated form of guanosine triphosphate used to cap an mRNA molecule in most eukaryotes

Question 22

microRNA (miRNA)

Answer 22

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

Question 23

molecular biology

Answer 23

the biochemical study of genetic basis for phenotype

Question 24

monocistronic

Answer 24

a form of gene organization resulting in transcription of an mRNA that contains coding sequence for a single gene or gene product

Question 25

missense mutation

Answer 25

a mutation in which the identity of an encoded amino acid had been changed

Question 26

mitosis

Answer 26

division of a eukaryotic somatic cell, after which the cell remains diploid

Question 27

mRNA (messenger RNA)

Answer 27

the single-stranded, edited copy of a gene ultimately translated into protein

Question 28

mRNA export

Answer 28

refers to the movement of spliced mRNA out of the nucleus to the cytoplasm

Question 29

mRNA processing

Answer 29

refers to the processes of polyadenylation, spicing, and addition of a 5’ cap structure

Question 30

multifactorial genetic diseases

Answer 30

those which require mutations of more than one gene, or particular combinations of multiple alleles, in order to produce disease.

often involving environmental influences

Question 31

multigene family

Answer 31

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

Question 32

mutagen

Answer 32

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

Question 33

mutation

Answer 33

a permanent change of the genetic material, either in a single gene or in the numbers or structures of the chromosomes

Question 34

ncRNA (non-coding RNA)

Answer 34

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

Question 35

nonsense mutation

Answer 35

a mutation in which an amino acid-encoding codon has been altered to a stop codon

Question 36

Northern blot

Answer 36

the transfer of size-seperated RNA fragments to a synthetic membrane for further studies

Question 37

nucleoside

Answer 37

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

Question 38

nucleosome

Answer 38

the repeated structure formed of dsDNA, octameric histones, and associated proteins in eukaryotes

Question 39

nucleotide

Answer 39

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

Question 40

null mutant

Answer 40

an organism that lacks any functional allele for a given gene or trait

Question 41

ochre mutation

Answer 41

one wherein a codon has been modified, resulting in the formation of a UAA stop codon

Question 42

okazaki fragments

Answer 42

short DNA fragments formed on the lagging strand of dsDNA during replication

Question 43

oligonucleotide

Answer 43

a short, continuous string of nucleotides. The prefix “oligo” means “several”

Question 44

oncogene

Answer 44

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

Question 45

oncogenic transformation

Answer 45

a change in the behavioral phenotype of a cell to one lacking in normal proliferative control, and often involving invasive characteristics

Question 46

open reading frame

Answer 46

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

Question 47

operator sequence

Answer 47

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

Question 48

operon

Answer 48

genes which are grouped together for coordinate regulation b the same regulator

Question 49

origin of replication

Answer 49

a site at which DNA replication is initiated

there is only 1 in bacterial chromosomes, but numerous origins in eukaryotic chromosomal DNA

Question 50

origin recognition complex

Answer 50

an organization of protein factors assembled at an origin of replication for the purpose of initiating transcription

Question 51

orthologs

Answer 51

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