Ch. 7 The cellular basis of inheritance Flashcards
alternation of generations
a life-cycle type in which the diploid and haploid stages alternate
aneuploid
an individual with an error in chromosome number; includes deletions and duplications of chromosome segments
autosome
any of the non-sex chromosomes
chiasmata
(singular = chiasma) the structure that forms at the crossover points after genetic material is exchanged
chromosome inversion
the detachment, 180° rotation, and reinsertion of a chromosome arm
crossing over
: (also, recombination) the exchange of genetic material between homologous chromosomes resulting in chromosomes that incorporate genes from both parents of the organism forming reproductive cells
diploid- dominant
a life-cycle type in which the multicellular diploid stage is prevalent
euploid
an individual with the appropriate number of chromosomes for their species
fertilization
the union of two haploid cells typically from two individual organisms
gametophyte
a multicellular haploid life-cycle stage that produces gametes
germ cell
a specialized cell that produces gametes, such as eggs or sperm
haploid -dominant
a life-cycle type in which the multicellular haploid stage is prevalent
interkinesis
a period of rest that may occur between meiosis I and meiosis II; there is no replication of DNA during interkinesis
karyogram
the photographic image of a karyotype
karyotype
the number and appearance of an individuals chromosomes, including the size, banding patterns, and centromere position
life cycle
the sequence of events in the development of an organism and the production of cells that produce offspring
meiosis
a nuclear division process that results in four haploid cells
meiosis I
the first round of meiotic cell division; referred to as reduction division because the resulting cells are haploid
meiosis II
the second round of meiotic cell division following meiosis I; sister chromatids are separated from each other, and the result is four unique haploid cells
monosomy
an otherwise diploid genotype in which one chromosome is missing
nondisjunction
the failure of synapsed homologs to completely separate and migrate to separate poles during the first cell division of meiosis
polyploid
an individual with an incorrect number of chromosome sets
recombinant
describing something composed of genetic material from two sources, such as a chromosome with both maternal and paternal segments of DNA
reduction division
a nuclear division that produces daughter nuclei each having one-half as many chromosome sets as the parental nucleus; meiosis I is a reduction division
somatic cell
all the cells of a multicellular organism except the gamete-forming cells
sporophyte
a multicellular diploid life-cycle stage that produces spores
synapsis
the formation of a close association between homologous chromosomes during prophase I
tetrad
two duplicated homologous chromosomes (four chromatids) bound together by chiasmata during prophase I
translocation
the process by which one segment of a chromosome dissociates and reattaches to a different, nonhomologous chromosome
trisomy
an otherwise diploid genotype in which one entire chromosome is duplicated
X inactivation
the condensation of X chromosomes into Barr bodies during embryonic development in females to compensate for the double genetic dose
