ap bio ch 10 vocab

heredity

the transmission of traits from one generation to the next

variation

differences between members of the same species

genetics

the scientific study of heredity and hereditary variation

genes

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

clone

an individual that is genetically identical to another individual.

sex chromosomes

A chromosome responsible for determining the sex of an individual.

autosomes

A chromosome that is not directly involved in determining sex; not a sex chromosome.

diploid cell

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

haploid cell

A cell containing only one set of chromosomes (n).

fertilization

The union of haploid gametes to produce a diploid zygote.

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.

reduction division

another name for meiosis I, the division where homologous pairs separate.

equational division

Another name for meiosis II because cells in meiosis II have the same number of chromosomes at the beginning and at the end of the process.

allele

Any of the alternative versions of a gene that may produce distinguishable phenotypic effects.

recombinant chromosomes

A chromosome created when crossing over combines the DNA from two parents into a single chromosome.

nonsister chromatids

Different chromatids (maternal and paternal) of the same chromosome.

gametes

A haploid reproductive cell, such as an egg or sperm.

somatic cells

Any cell in a multicellular organism except a sperm or egg or their precursors.

locus

A specific place along the length of a chromosome where a given gene is located.

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.

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.

karyotype

A display of the chromosome pairs of a cell arranged by size and shape.

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.

zygote

The diploid cell produced by the union of haploid gametes during fertilization; a fertilized egg.

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.

synapsis

the pairing and physical connection of duplicated homologous chromosomes during prophase I of meiosis

crossing over

The reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosis.

independent assortment

Homologous pairs of chromosomes orient randomly at metaphase I of meiosis