Chapter 11 Flashcards
a haploid cell, an egg or sperm. haploid cells fuse during sexual reproduction to form a diploid zygote
gametes
division of diploid cells to haploid progeny consisting of 2 sequential rounds of nuclear and cellular division
meiosis
any of cells of an organism’s body other than reproductive cells
somatic cells
the fusion of nuclei of an egg and sperm cell which initiates development of a new individual
fertilization
a fertilized egg
zygote
a specialized gamete-producing organ in which the germ cells collect. are the primary source of sex hormone in vertebrates: ovaries in females and testes in males
gonads
the male gonad. in male vertebrates, they secrete androgens and steroid hormones that stimulate and control the development and maintenance of male reproductive systems
testis
a haploid cell that develops into mature sperm cell when meiosis is complete
spermatozoa (sperm)
in animals, the female gonad,which produces female gametes and reproductive hormones. in flowering plants, the enlarged base of a carpel in which 1 or more ovules develop into seeds
ovaries
the formation of male and female gametes
gametogenesis
the chromosome derived from the male parent of an organism
paternal chromosome
the chromosome derived from the female parent of an organism
maternal chromosome
1 of 2 or more versions of a gene
alleles
an organism or cell with only one copy of each type of chromosome in its nuclei
haploid
the first division of the meiotic cell cycle in which homologous chromosomes pair and undergo an exchange of chromosome segments, and then the homologous chromosomes separate, resulting in 2 cells each with the haploid number of chromosomes and with each chromosome still consisting of 2 chromatids
meiosis I
the second division of the meiotic cell cycle in which the sister chromatids in each of the 2 cells produced by meiosis I separate and segregate into different cells resulting in 4 cells each with the haploid number of chromosomes
meiosis II
a brief interphase separating the 2 meiotic division
interkinesis
the failure of homologous pairs to separate during the first meiotic division or of chromatids to separate during the second meiotic division
nondisjunction
chromosomes that are different in male and female individuals of the same species
sex chromosomes
chromosomes that contain nonparental combinations of alleles. in eukaryotes, they are generated by crossing-over in meiosis
recombinant chromosomes
the process by which the combinations of alleles for different genes in 2 parental individuals become shuffled into new combinations in offspring individuals
genetic recombination
nonparental combinations of alleles. in eukaryotes they results from crossing-over in meiosis
genetic recombinants
phenotype with a different combination of traits from those of the original parents
recombinants
mode of reproduction in which male and female parents produce offspring through the union of egg and sperm generated by meiosis
sexual reproduction
mendel’s principle that the alleles of the genes that govern 2 characters assort independently during formation of gametes. mechanistically this is case because any combination of chromosomes may be segregated to the spindle poles during meiosis I
independent assortment
