AP Biology Vocabulary & Roots: Ch. 13
1. allele- Any of the alternative versions of a gene that produce distinguishable phenotypic effects.
2. alternation of generations- A life cycle in which there is both a multicellular diploid form, the
sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants and some
algae.
3. asexual reproduction-The generation of offspring from a single parent that occurs without the
fusion of gametes (by budding, division of a single cell, or division of the entire organism into two
or more parts). In most cases, the offspring are genetically identical to the parent.
4. asexual reproduction-The generation of offspring from a single parent that occurs without the
fusion of gametes (by budding, division of a single cell, or division of the entire organism into two
or more parts). In most cases, the offspring are genetically identical to the parent.
5. autosome- A chromosome that is not directly involved in determining sex; not a sex
chromosome.
6. chiasma- (ki-az´-muh, ki-az´-muh-tuh) The X-shaped, microscopically visible region where
homologous nonsister chromatids have exchanged genetic material through crossing over during
meiosis, the two homologs remaining associated due to sister chromatid cohesion.
7. clone- (1) A lineage of genetically identical individuals or cells. (2) In popular usage, a single
individual organism that is genetically identical to another individual. (3) As a verb, to make one or
more genetic replicas of an individual or cell. See also gene cloning
8. crossing over-The reciprocal exchange of genetic material between nonsister chromatids during
prophase I of meiosis.
9. diploid cell- A cell containing two sets of chromosomes (2n), one set inherited from each parent.
10. gametophyte- In organisms (plants and some algae) that have alternation of generations, the
multicellular haploid form that produces haploid gametes by mitosis. The haploid gametes unite and
develop into sporophytes.
11. gene-A discrete unit of hereditary information consisting of a specific nucleotide sequence in
DNA (or RNA, in some viruses).
12. genetics-The scientific study of heredity and hereditary variation.
13. haploid cell- A cell containing only one set of chromosomes (n).
14. heredity-The transmission of traits from one generation to the next.
15. homologous chromosomes-A pair of chromosomes of the same length, centromere position,
and staining pattern that possess genes for the same characters at corresponding loci. One
homologous chromosome is inherited from the organism’s father, the other from the mother. Also
called homologs, or a homologous pair.
16. karyotype- A display of the chromosome pairs of a cell arranged by size and shape.
17. life cycle-The generation-to-generation sequence of stages in the reproductive history of an
organism.
18. locus- A specific place along the length of a chromosome where a given gene is located.
19. meiosis-A modified type of cell division in sexually reproducing organisms consisting of two
rounds of cell division but only one round of DNA replication. It results in cells with half the
number of chromosome sets as the original cell.
20. meiosis I -The first division of a two-stage process of cell division in sexually reproducing
organisms that results in cells with half the number of chromosome sets as the original cell.
21. meiosis II-The second division of a two-stage process of cell division in sexually reproducing
organisms that results in cells with half the number of chromosome sets as the original cell.
22. recombinant chromosome-A chromosome created when crossing over combines the DNA
from two parents into a single chromosome.
23. sex chromosome-A chromosome responsible for determining the sex of an individual.
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24. sexual reproduction-A type of reproduction in which two parents give rise to offspring that
have unique combinations of genes inherited from the gametes of the parents.
25. somatic cell-Any cell in a multicellular organism except a sperm or egg.
26. spore- (1) In the life cycle of a plant or alga undergoing alternation of generations, a haploid
cell produced in the sporophyte by meiosis. A spore can divide by mitosis to develop into a
multicellular haploid individual, the gametophyte, without fusing with another cell. (2) In fungi, a
haploid cell, produced either sexually or asexually, that produces a mycelium after germination
27. sporophyte- In organisms (plants and some algae) that have alternation of generations, the
multicellular diploid form that results from the union of gametes. The sporophyte produces haploid
spores by meiosis that develop into gametophytes.
28. synapsis-The pairing and physical connection of replicated homologous chromosomes during
prophase I of meiosis.
29. variation-Differences between members of the same species.
30. zygote-The diploid product of the union of haploid gametes during fertilization; a fertilized egg.
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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