Unit 4 Terminology Flashcards
Wild type
The phenotype most commonly observed in natural populations; also refers to the individual with that phenotype
Sex-linked gene
A gene locate on either sex chromosome
X-linked gene
A gene located on the X chromosome
Linked genes
Genes located close enough together on a chromosome that they tend to be inherited together
Recombinant chromosome
A chromosome created when crossing over combines DNA from two parents into a single chromosome
Genetic map
An ordered list of genetic loci along a chromosome
Linkage map
A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes
Nondisjunction
An error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids fail to separate properly form each other
Aneuploidy
A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number
Polyploidy
A chromosomal alteration in which the organisms possesses more than two complete chromosome sets
Deletion
A deficiency in a chromosome resulting from the loss of a fragment. Also a mutational loss of one or more nucleotide pairs from a gene
Duplication
An aberration in chromosome structure due to fusion with a fragment form a homologous chromosome
Inversion
An aberration in chromsome structure resulting from reattachment of a chromosomal fragment in a reverse orientation to the chromosome from which it originated
Translocation
An aberration chromosome structure resulting from attachment a chromosomal fragment to a non homologous chromosome
Syndrome
A set of symptoms resulting from a common cause presenting a clinical picture of disease organic disorder
Genomic imprinting
A phenomenon in which expression of an allele in offspring depends on whether the allele is inherited from the male or female parent
Transformation
A change in genotype and phenotype due to the assimilation of external DNA by cell
Bacteriophage
A virus that infects bacteria
Virus
An infectious particle incapable of replicating outside of a cell consisting of an RNA or DNA genome surrounding by a protein coat.
Double Helix
The form of native DNA, referring to its two adjacent antiparallel polynucleotide strands wound around an imaginary axis into a spiral shape
Antiparallel
Referring to the arrangement of the sugar-phosphate backbones in a DNA double helix
Semiconservative model
Type of DNA replication in which the replicated double helix consists of one old strand, derived form the parental molecule, and one newly made strand
Replication fork
A Y-shaped region on a replicated DNA molecule where the parental strands are being inbound and new strands are being synthesized
Helicase
An enzyme that unwinds the double helix of DNA at replication forks, separating the two strands and making them available to template strands
Single-strand binding protein
A protein that binds to the unpaired DNA strands during DNA replication, stabilizing them and holding them apart while they serve as templates for the synthesis of complementary strands of DNA
Topoisomerase
A protein that breaks, swivels, and regions DNA strands
Primer
A short stretch of RNA with a free 3’ end bound by complementary base paring to the template strand and elongated with DNA nucleotides during DNA replication
Primase
An enzyme that join RNA nucleotides to make a proper during DNA replication, using the parental DNA strand as a template
DNA polymerase
An enzyme tha catalyses the elongation of new DNA by the addition of nucleotides to the 3’ end of an existing chain
Leading strand
The new complementary DNA strand synthesized continuously along the template strand toward the replication fork
Lagging strand
A discontinuously synthesized DNA strand that elongates b means of Okazaki fragments
Okazaki fragment
A short segment of DNA synthesized away from the replication fork on the template strand during DNA replication
DNA ligase
A linking enzyme that catalyzes the covalent bonding of the 3’ end of on DNA grandaunt to the 5’ end of another DNA fragment
Nucease
An enzyme that cuts DNA or RNA
Nucleotide excision repair
A system that removes and then correctly replaces a damaged segment of DNA using the undamaged stand as a guide
Telomere
The region of repetitive DNA a the end of a eukaryotic chromosomes DNA molecule
Telomerase
An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells
Histone
A small protein with a high proportion of positivity charged amino acids that binds to the negatively charged DNA and plays a key role in chromatin structure
Nucleosome
The basic, beadlike unit of DNA packing in eukaryotes, consisting of a segment of DNA wound around a histone core
Gene Expression
The process by which information encoded in DNA directs the synthesis of proteins or RNA’s
Transcription
The synthesis of RNA using a DNA template
Translation
The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule
Messenger RNA
A type of RNA, synthesized using a DNA template that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein
Ribosome
A complex of rRNA and protein molecules that function as a site of protein synthesis in the cytoplasm; consists of a large and a small subunit
Primary transcript
An initial RNA transcript from any gene; also called pre-mRNA when transcribed from a protein-coding gene
Triplet code
A genetic information system in which a set of three-nucleotide-long words specify the amino acids for polypeptide chains
Template strand
The DNA strand that provides the pattern for ordering, by complementary base paring, the sequence of nucleotides in an RNA transcript
Codon
A three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of genetic code
Reading frame
On an mRNA, the triplet grouping of ribonucleotides used by the translation machinery during polypeptide synthesis
Promoter
A specific nucleotide sequence in the DNA of a gene that binds RNA polymerase, positioning it to start transcribing RNA at the appropriate place
Terminator
In bacteria, a sequence of nucleotides in the DNA that marks the end of a gene and signals RNA polymerase to release the newly made RNA molecule and detach fro the DNA
Transcription unit
A region of DNA that is transcribed into an RNA molecule
Start point
In transcription, the nucleotide position on the promoter where RNA polymerase begin synthesis of RNA
Transcription factor
A regulatory protein that binds to DNA and affects transcription of specific genes
Transcription initiation complex
The completed assembly of transcription factors and RNA polymerase bound to a promoter
RNA splicing
After synthesis of a eukaryotic primary RNA transcript, the removal of portions of the transcript (introns) that will not be included in the mRNA and the joining together of the remains portions (exons)
Intron
A noncoding, intervening sequence within a primary transcript that is removed from the transcript during RNA precision; also refers to the region of DNA from which this sequence was transcribed
Exons
A sequence within a primary transcript that remains in the RNA molecules that splices RNA by interacting wit hate ends of an RNA intron, releasing the intron and joining the two adjacent exons
Spliceosome
A large complex made up of proteins and RNA molecules that splices RNA by interacting with the ends of an RNA intron, releasing the intron and joining the two adjacent exons
Ribozyme
An RNA molecule that function as an enzyme, such as an intron that catalyzes is own removal during RNA splicing
Domain
A discrete structural and functional region of a protein
Transfer RNA
An RNA molecule that functions as a translator between nucleic acids and proteins by carrying specific amino acids to the ribosome, where it recognizes the appropriate codons in the mRNA
An anticodon
A nucleotide triplet at on end of a tNA molecule that basepairs wit ha particular complementary codon on an mRNA molecule
Wobble
Flexibility in the base pairing rules in which the nucleotide at the 5’ end of a tRNA anticodon can form hydrogen bones with more than one kind of use in the third position (3’ end) of a codon
Ribosomal RNA
RNA molecules that, together with protein, make up ribosomes; the most abundant type of RNA
Polyribosome
A group of several ribosome attached to, and translating, the same mRNA molecule
Signal peptide
A sequence of about 20 amino acids at or near the leading end of a polypeptide that targets it to the endoplasmic reticulum or other organelles in eukaryotic cell.
Mutation
A change in the nucleotide sequence of an organisms’s DNA or in the DNA or RNA of a virus
Point mutation
A change in a single nucleotide pari of a gene
Frameshift mutation
A mute occurring when nucleotides are inserted in or deleted from a gene and the number inserted or deleted is not a multiple of three, resulting in the improper grouping of the subsequent nucleotides into codons
Mutagen
A chemical or physical agent that interacts with DNA and can cause a mutation
Gene
A gene is a region of DNA that can be expressed to produce a final functional product the is either a polypeptide or an RNA molecule
Operator
In bacteria and phage DNA, a seance of nucleotides near the start of an operon to which an operon to which ha n active repressor can attach . The binding of the repressor events RNA polymerase fro matching o the promoter and transcribing the genes of the operon
Operon
A unit of genetic functions found in bacteria and phages, consisting of a promoter , an operator, and a coordinately regulated cluster of genes whose products function in a common pathway
Promotor
A specific nucleotide sequence in the DNA of a gene that binds RNA polymerase , positioning it to start transcribing RNA at the appropriate place
Repressor
A protein that inhibits gene transcription
Corepressor
A small molecule that binds to bacterial repressor protein and changes the protein;s shape allowing it to bind to the operator and switch and operon off
Inducer
A specific small molecule the binds to a bacterial repressor protein and changes the repressors’s she so that it cannot bind to an operator, this switching an operon on
DNA methylation
The presence or addition of methyl groups on the DNA bases
Epigenetic inheritance
Inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence of a genome
Control element
A segment of noncoding DNA that help regulate transcription of a gene by serving as bind sign site for transcription factor
Enhancer
A segment of eukaryotic DNA contains multiple control elements, usually located far from the gene whose transcription it regulates
Alternative RNA splicing
Producing different mRNA molecules fro the same primary transcript, depending on which hRNA segments are treated as exons and which as introns
Proteasome
A giant protein complex that recognizes and destroys proteins tagged fro elimination by the small protein ubiquitin
MicroRNA (miRNA)
a small, single-stranded RNA molecule the associates with protein in a complex hat can degrade or prevent translation of an mRNA with a complementary sequence
RNA interference (RNAi)
Synthetic double-stranded RNA molecules that match the sequence of a particular gene to trigger the breakdown of the demes’s mRNA
Small interfering RNA (siRNA)
A single-stranded RNA molecule made from a long, linear, double-stranded RNA molecule. the siRNA associate with protein to degrade or prevent translation of an mRNA with a complementary sequence
Differentiation
The process by which a cell or group of cells become specialized in structure and function
Morphogenesis
The cellular and tissue-based processes by which an organism takes shape
Cytoplasmic determinant
A maternal substance that when placed into an egg influences the early development by regulating the expressions of genes that affect the developmental fate of cells.
Induction
The process in which one group of embryonic cells influences the development of another, usually by causing changes in gene expression
Determination
The progressive restriction of developmental potential in who the possible fate of each cell becomes more limited as an embryo develops
Homeotic gene
Any of the master regulatory genes that control placement and spatial organization of body parts by controlling the developmental fate of groups of cells.
Oncogene
A gene that is involved in triggering molecular events the can lead to cancer
Proto-oncogene
A normal gene that has the potential to become and oncogene
Virus
An infectious particle incapable of replicating outside of a cell, consisting of an RNA or DNA genome surrounded by a protein coat
Capside
The protein shell tha encloses a viral genome
Viral envelope
A membrane, derived from membranes of the host cell, which closes the capsid
Bacteriophage
A virus that infects bacteria;also called a phage
Lysogenic cycle
A type of phage replicative cycle in which the viral genome becomes incorporated into the bacterial host chromosome as a prophage, is replicated along wit the chromosome, and does not kill the host
Lytic Cycle
A type of phage replicative cycle resulting in the release of new phages by lysis of the host cell
Prophage
A phage genome that has been inserted into a specific site on a bacterial chromosome
Vaccine
A harmless variant or derivative of a pathogen the stimulates a host’s immune system to mount defences agains the pathogen
Epidemic
A general outbreak of disease
Pandemic
A GLOBAL EPIDEMIC
Viroid
A plant pathogen consisting of a molecule of naked, circular RNA a few hundred nucleotides long
Prion
A infectious agent the tis a misfiled version of a normal cellular protein
Pseudogene
A DNA segment that formerly functioned as a gene but has become inactive because of mutation
Repetitive DNA
Nucleotide sequences, usually noncoding, which are present in many copies in a eukaryotic genome
Transposable element
A segment of DNA that cane move within the genome of a cell m=by means of DNA or RNA intermediate
Transposon
A transposable element that moves within a genome by means of DNA intermediate
Retrotransposon
A transposable element that moves within a genome by means of RNA intermediate
Multigene family
A collection of genes with similar or identical sequences
Homeobox
A 180 nucleotide sequence within homeotic genes and some other developmental genes
