Chapter 10 Meiosis Flashcards
Allele
Slightly different nucleotide sequences of a gene
Autosome
pairs of chromosomes with nearly identical DNA sequences and that are found in diploid cells of both sexes
Chiasma
crosses in a nuclei, remnants of binding enzymes and proteins
Crossing Over
The mutual exchange of DNA between maternal and paternal chromosomes at chiasmata
Homologous Chromosome
a set of chromosomes that contain genes that control the same inherited characteristics
Down Syndrome
Trisomy 21, missing chromosome 21
Karyotype
a complete set of chromosomes from a single cell
Locus
a gene consists of a sequence of nucleotides at a specific place on a chromosome
Haploid
if a cell contains only one member of each pair of homologues
Sex Chromosome
males have x&Y chromosomes, females have a pair of X chromosomes
Meiosis
a specialized type of nuclear division, in which a diploid nucleus divides twice, producing four haploid nuclei, and cytokinesis which packages the four nuclei into separate cells
Jacob Syndrome
male offspring with one x chromosome and two y chromosomes, occasionally taller then average
Polypoid
more than two copies of each homologous chromosome in each cell
Klinefelter Syndrome
males born with two x chromosomes and one y chromosome, small testes and low sperm counts
Meiosis II
seperates the chromatids into independent chromosomes and parcels one chromosome into each of two daughter nuclei
Nondisjunction
Errors in meiosis, resulting in wrong numbers of chromosomes
Recombination
the formation of chromosomes with combinations of alleles that differ from those of either parent
Sexual Reproduction
Offspring are are produced through the union of Gametes
Trisomy X
female offspring with three X chromosomes, frequently taller and have learning disabilities
Turner Syndrome
female baby with only one x chromosome, ovaries degenerate during development
Trisomy 21
Downs syndrome, missing chromosome 21
Zygote
a diploid fertilized egg
