1.
allele: one of the alternative forms of a gene that governs a characteristic, such as hair color
2.
crossing over: exchange of genetic material between nonsister chromatids from homologous chromosomes during prophase I of meiosis; results in new allele combinations
3.
diploid: cell with two of each kind of chromosome; is said to contain a diploid, or 2n, number of chromosomes
4.
dominant: trait that will show up in an organism's phenotype if gene is present
5.
egg: haploid female sex cell produced by meiosis
6.
fertilization: fusion of male and female gametes
7.
gametes: male and female sex cells; sperm and eggs
8.
genetic recombination: major source of genetic variation among organisms caused by reassortment or crossing over during meiosis
9.
genetics: the branch of biology that studies heredity
10.
genotype: genetic makeup of an organism
11.
haploid: cell with one of each kind of chromosome; is said to contain a haploid or n, number of chromosomes
12.
heredity: the passing of genetic traits from parent to offspring
13.
heterozygous: having two different alleles for a trait
14.
homologous chromosome: paired chromosomes with genes for the same traits arranged in the same order.
15.
homozygous: having two identical alleles for a trait
16.
hybrid: the offspring of parents that have different forms of a trait
17.
law of independent assortment: Mendelian principle stating that genes for different traits are inherited independently of each other
18.
law of segregation: Mendelian principle explaining that because each plant has two different alleles, it can produce two different types of gametes. During fertilization, male and female gametes randomly pair to produce four combination of alleles
19.
meiosis: type of cell division that produces four cells, each with half as many chromosomes as the parent cell
20.
nondisjunction: failure of homologous chromosomes to separate properly during meiosis; results in gametes with too many or too few chromosomes
21.
phenotype: physical characteristics of an organism
22.
pollination: the transfer of pollen from male reproductive structures to female reproductive structures in plants
23.
recessive: The inherited characteristic often masked by the dominant characteristic and not seen in an organism.
24.
sexual reproduction: pattern of reproduction that involves the production and subsequent fusion of haploid sex cells
25.
sperm: haploid male sex cells produced by meiosis
26.
trait: a characteristic that an organism can pass on to its offspring through its genes.
27.
zygote: fertilized egg, diploid cell formed when a sperm fertilizes an egg
