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