Genetics & Sexual Reproduction Vocab

Biology chapter 5

allele

alternate form that a single gene may have for a particular trait

crossing over

exchange of chromosomal segments between a pair of homologous chromosomes during prophase 1 of meiosis

diploid

having two copies of each chromosome

dominant

Mendel’s name for a specific trait that appeared in the F1 generation

fertilization

process by which haploid gametes combine, forming a diploid cell with 2n chromosomes, with n chromosomes from the female parent and n chromosomes from the male parent

gamete

a haploid sex cell, formed by meiosis, that can combine with another haploid sex cell and produce a diploid fertilized egg

gene

functional unit that controls inherited trait expression that is passed on from one generation to another generation

genetic recombination

new combination of genes produced by crossing over and independent assortment

genetics

science of herdity

genotype

an organism’s allele pairs

haploid

cell with half the number of chromosomes (n) as a diploid (2n) cell

heterozygous

organism with two different alleles for a specific trait

homologous chromosome

one or two paired chromosomes, one from each parent, that carries genes for a specific trait at the same location

homozygous

organism with two of the same alleles for a specific trait

hybrid

organism heterozygous for a specific trait

law of independent assortment

Mendelian law stating that a random distribution of alleles occurs during the formation of gametes

law of segregation

Mendelian law stating that two alleles for each trait separate during meiosis

meiosis

reduction division process, occurring only in reproductive cells, in which one diploid (2n) produces 4 haploid (n) cells that are not genetically identical

phenotype

observable characteristics that is expressed as a result of an allele pair

polyploidy

having one or more extra sets of all chromosomes, which, in polyploid plants, can often result in greater size and better growth and survival

recessive

Mendel’s name for a specific trait hidden or masked in the F1 generation