Chapter 15 Vocabulary Flashcards
A chromosomal aberration in which one or more chromosomes area present in extra copies or are deficient in number.
Aneuploidy
A dense object lying along the inside of the nuclear envelope in cells of female mammals, representing a highly condensed, inactivated X chromosome.
Barr body
A basic principle in biology stating that genes are located on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns.
Chromosome Theory of Inheritance
A human genetic disease caused by the presence of an extra chromosome 21; characterized by mental slowness and heart and respiratory defects.
Down syndrome
A human genetic disease caused by a sex-linked recessive allele; characterized by progressive weakening and a loss of muscle tissue.
Duchenne muscular dystrophy
An aberration in chromosome structure due to fusion with a fragment from a homologous chromosome, such that a portion of a chromosome is doubled.
Duplication
An ordered list of genetic loci (genes or other genetic markers) along a chromosome.
Genetic map
General term for the production of offspring with combinations of traits that differ from those found in either parent.
Genetic recombination
A phenomenon in which expression of an allele in offspring depends on whether the allele is inherited from the male or female parent.
Genomic imprinting
A human genetic disease caused by sex-linked recessive allele resulting in the absence of one or more blood-clotting proteins; characterized by excessive bleeding following injury.
Hemophilia
An aberration in chromosome structure resulting from reattachment of a chromosomal fragment in a reverse orientation to the chromosome from which it originated.
Inversion
A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes.
Linkage map
Genes located close enough together on a chromosome that they tend to be inherited together.
Linked genes
A unit of measurement of the distance between genes. One of these units is equivalent to a 1% recombination frequency.
Map unit
Referring to a cell that has only one copy of a particular chromosome instead of the normal two.
Monosomic
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 from each other.
Nondisjunction
An offspring with a phenotype that matches one of the former phenotypes; also refers to the phenotype itself.
Parental type
A chromosomal alteration in which the organism possesses more than two complete chromosome sets. It is the result of an accident of cell division.
Polyploidy
A gene located on a sex chromosome (usually the X chromosome), resulting in a distinctive pattern of inheritance.
sex-linked gene
An aberration in chromosome structure resulting from attachment of a chromosomal fragment to a non-homologous chromosome.
(2) Third stage of elongation cycle when RNA carrying growing polypeptide moves from the A site to the P site on ribosome (protein synthesis).
(3) Transport of organic nutrients in the phloem of vascular plants.
Translocation
Referring to a diploid cell that has three copies of a particular chromosome instead of the normal two.
Trisomic
An individual with the phenotype most commonly observed in natural populations; also refers to the phenotype itself.
Wild type
