AP Biology Vocabulary & Roots: Ch. 15
1. aneuploidy- A chromosomal aberration in which one or more chromosomes are present in extra
copies or are deficient in number.
2. Barr body-A dense object lying along the inside of the nuclear envelope in cells of female
mammals, representing a highly condensed, inactivated X chromosome.
3. chromosome theory of inheritance-A basic principle in biology stating that genes are located on
chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance
patterns.
4. crossing over-The reciprocal exchange of genetic material between nonsister chromatids during
prophase I of meiosis.
5. cytogenetic map-A chart of a chromosome that locates genes with respect to chromosomal
features distinguishable in a microscope.
6. dendrite-One of usually numerous, short, highly branched extensions of a neuron that receive
signals from other neurons.
7. Down syndrome-A human genetic disease caused by the presence of an extra chromosome 21;
characterized by mental retardation and heart and respiratory defects.
8. Duchenne muscular dystrophy-A human genetic disease caused by a sex-linked recessive
allele; characterized by progressive weakening and a loss of muscle tissue.
9. duplication-An aberration in chromosome structure due to fusion with a fragment from a
homologous chromosome, such that a portion of a chromosome is duplicated.
10. genetic map-An ordered list of genetic loci (genes or other genetic markers) along a
chromosome.
11. genetic recombination-General term for the production of offspring with combinations of traits
that differ from those found in either parent.
12. 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.
13. hemophilia- A human genetic disease caused by a sex-linked recessive allele resulting in the
absence of one or more blood-clotting proteins; characterized by excessive bleeding following
injury.
14. inversion-An aberration in chromosome structure resulting from reattachment of a
chromosomal fragment in a reverse orientation to the chromosome from which it originated.
15. linkage map-A genetic map based on the frequencies of recombination between markers during
crossing over of homologous chromosomes.
16. linked genes-Genes located close enough together on a chromosome that they tend to be
inherited together.
17. map unit-A unit of measurement of the distance between genes. One map unit is equivalent to a
1% recombination frequency.
18. monosomic-Referring to a cell that has only one copy of a particular chromosome instead of the
normal two.
19. 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 from each other.
20. parental type-An offspring with a phenotype that matches one of the parental phenotypes; also
refers to the phenotype itself.
21. polyploidy- A chromosomal alteration in which the organism possesses more than two
complete chromosome sets. It is the result of an accident of cell division.
22. sex-linked gene- A gene Located on A sex chromosome (usually the X chromosome), resulting
in A distinctive pattern of inheritance.
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23. translocation- (1) An aberration in chromosome structure resulting from attachment of a
chromosomal fragment to a nonhomologous chromosome.
24. trisomic-Referring to a diploid cell that has three copies of a particular chromosome instead of
the normal two.
25. wild type-An individual with the phenotype most commonly observed in natural populations;
also refers to the phenotype itself.
Word Roots
a- = not or without (asexual: type of reproduction not involving fertilization)
-apsis = juncture (synapsis: the pairing of replicated homologous chromosomes during prophase I
of meiosis)
auto- = self (autosome: the chromosomes that do not determine gender)
chiasm- = marked crosswise (chiasma: the X-shaped microscopically visible region representing
homologous chromosomes that have exchanged genetic material through crossing over during
meiosis)
di- = two (diploid: cells that contain two homologous sets of chromosomes)
fertil- = fruitful (fertilization: process of fusion of a haploid sperm and a haploid egg cell)
haplo- = single (haploid: cells that contain only one chromosome of each homologous pair)
homo- = like (homologous: like chromosomes that form a pair)
karyo- = nucleus (karyotype: a display of the chromosomes of a cell)
meio- = less (meiosis: a variation of cell division that yields daughter cells with half as many
chromosomes as the parent cell)
soma- = body (somatic: body cells with 46 chromosomes in humans)
sporo- = a seed; -phyte = a plant (sporophyte: the multicellular diploid form in organisms
undergoing alternation of generations that results from a union of gametes and that meiotically
produces haploid spores that grow into the gametophyte generation)
syn- = together; gam- = marriage (syngamy: the process of cellular union during fertilization)
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