A | B |
CENTROMERES | attach sister chromatids together in the middle (intersection of the X) |
HOMOLOGOUS CHROMOSOMES | chromosomes that are similar size and carrying same traits |
chromosomes | genes are found on these structures |
crossing-over | pieces of homologous chromosomes are exchanged during meiosis |
karyotype | a chart showing all of an organism's chromosomes, arranged in homologous pairs |
CHROMOSOMES | compacted versions of chromatin |
HAPLOID | 1 copy (N) of each chromosomes in gametes. Example: 23 chromosomes in humans |
DIPLOID | 2 copies (2N) of each chromosome. Example: 46 chromosomes in humans |
SOMATIC | referred to as diploid body cells since they make up most of body tissues and organ, DNA is not passed on |
GAMETES | referred to as sex cells, haploid egg in females, haploid sperm in males, DNA is passed on |
MEIOSIS | cell division resulting one cell dividing twice to form 4 haploid daughter cells |
SEXUAL | two parents, genetic diversity as a result of meiosis |
ASEXUAL | one parent, no genetic diversity, offspring identical to parent as in mitosis |
PROPHASE I | stage in which crossing over between homologous chromosomes occurs |
HOMOLOGOUS CHROMOSOMES | matching chromosomes from each parent |
ANAPHASE I | homologous chromosomes separate go from 2n to n |
METAPHASE I | homologous chromosomes line up across the equatorial plate |
PROPHASE II | 2ND division when spindle fibers form |
MEIOSIS II | division that involves haploid number of chromosomes |
MEIOSIS I | division that involves diploid number of chromosomes |
crossing over | chromosomal segments are exchanged between homologous chromosomes |
METAPHASE II | 2nd division when chromosomes line up at equator |
ANAPHASE II | 2nd division when chromosomes are pulled by apart by spindle fibers attached to centromeres |
TELOPHASE II | 2nd division which forms 4 nuclei |
zygote | fertilized egg |
polar bodies | form 3 as a result of meiosis in females, disintegrate |
ovum | single gamete formed as a result of meiosis in females |
TELOPHASE I | during this stage, there is a complete haploid set of chromosomes (but each chromosome still has two sister chromatids) |
spermatogensis | meiosis resulting in production of sperm cells in males |
oogenesis | meiosis resulting in production of ova (egg) cells in females |
spermatids | gamete formed as a result of meiosis in males |
ovum | always carries an X chromosome |
spermatids | may carry an X or y chromosome |
interkinesis | short intermediate stage between meiosis I and meiosis II |
karyokinesis | division of the nucleus |
tetrads | foursome during meiosis made by two homologous chromosomes that have each already replicated into a pair of sister chromatids |
syngamy | fusion of two different cells in sexual reproduction |
gametes | organisms reproductive cells |