AP Biology Chapter 13 Key Terms and Rooots

alternation of generations
life cycle in which there is both a multicellular diploid form, the sphorophyte, and a multi cellulare haploid form, the gametophyte; characteristic of plants

asexual reproduction
a type of reproduction involving only one parent that produces genetically identical offspring by budding or by the division of a single cell or the entire organism into two or more pairs

autosome
a chromosome that is not directly involved in determining sex, as opposed to a sex chromosome

chiasmata
the x shaped, microscopically visible region representing homologous chromatids that have exchanged genetic material through crossing over during mitosis

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.

crossing over
the reciprocal exchange of genetic material between nonsister chromatids during synapsis of meiosis I

diploid cell
a cell containing two sets of chromosomes (2n), one set inherited from each parent

fertilization
the union of haploid gametes to produce a diploid zygote

gamete
a haploid cell such as an egg or sperm. gametes unite during sexual reproduction to produce a diploid zygote.

gametophyte
the multicellular haploid form in organisms undergoing alternation of generations that mitotically produces haploid gametes that unite and grow into the sporophyte generation

gene
discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA in some viruses)

genetics
the scientific study of heredity and hereditary variation

haploid cell
a cell containing only one set of chromosomes (n)

heredity
the transmission of traits from one generation to the next

homologous chromosome
chromosome pairs of the same lenght, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. One comes from the mother, the other from the father.

Karyotype
a method of organizing the chromosomes of a cell in relation to number, size, and type

life cycle
the generation-to-generation sequence of stages in the reproductive history of an organism

locus
a particular place along the length of a certain chromosome where a given gene is located

meiosis
a two stage type of cell division in sexually reproducing organisms that results in cells with half the chromosome number of the original cell

meiosis I
the first division of a two stage process of cell division

meiosis II
the second division of a two stage process of cell division

recombinant chromosomes
chromosomes created when crossing over combines the DNA from two parents into a single chromosome

sex chromosomes
one of the pair of chromosomes responsible for determining the sex of an individual

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 two parents

somatic cell
any cell in a multicellular organism except a sperm cell or an egg cell

spore
in the life cycle of a plant or alga undergoing alternation of generations, a meiotically produced haploid cell that divides mitotically, generating a multicellular individual, the gametophyte, without fusing with another cell

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

synapsis
the pairing of replicated homologous chromosomes during prophase I of meiosis

syngamy
the process of cellular union during fertilization

tetrad
a paired set of homologous chromosomes, each composed of two sister chromatids. form during prophase I of meiosis

variation
differences between members of the same species

zygote
the diploid product of the union of haploid gametes in conception; a fertilized egg

-apsis
juncture

a-
not or without

auto-
self

chiasm-
marked crosswise

di-
two

fertil-
fruitful

haplo-
single

homo-
like