Test 3

clone

(1) A lineage of genetically identical individuals or cells. (2) In popular usage, an individual 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.

fertilization

(1) The union of haploid gametes to produce a diploid zygote. (2) The addition of mineral nutrients to the soil.

haploid cell

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

diploid cell

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

recombinant chromosome

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

gene

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

karyotype

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

gamete

A haploid reproductive cell, such as an egg or sperm. Gametes unite during sexual reproduction 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.

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.

locus

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

sexual reproduction

A type of reproduction in which two parents give rise to offspring that have unique combinations of genes inherited from both parents via the gametes.

variation

Differences between members of the same species.

zygote

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

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.

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.

life cycle

The generation-to-generation sequence of stages in the reproductive history of an organism.

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.

heredity

The transmission of traits from one generation to the next.