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Chpater 8
Vocabulary
Term | Definition |
---|---|
Chromosomes | in a eukaryotic cell, one of the structures in the nucleus that are made up of DNA and protein; in a prokaryotic cell, the main ring of DNA. |
histone | a type of protein molecule found in the chromosomes of eukaryotic cells but not prokaryotic cells. |
chromatid | one of the two strands of a chromosome that become visible during meiosis or mitosis. |
centromere | the region of the chromosome that holds the two sister chromatids together during mitosis. |
chromatin | the material that makes up both mitotic and interphase chromosomes; a complex of proteins and DNA strands that are loosely coiled such that translation and transcription can occur. |
sex chromosome | one of the pair of chromosomes that determine the sex of an individual. |
autosome | any chromosome that Is not a sex chromosome |
homologous chromosome | chromosomes that have the same sequence of genes, that have the same structure, and that pair during meiosis. |
karyotype | a micrograph of the array of chromosomes visible in a cell during metaphase; a graphical display that shows an individual's chromosomes arranged in homologous pairs and in order of diminishing size |
diploid | a cell that contains two haploid sets of chromosomes |
haploid | describes a cell, nucleus, or organism that had only one set of unpaired chromosomes. |
binary fission | a form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size. |
mitosis | in eukaryotic cells, a process of cell division that forms two new nuclei, each of which has the same number of chromosomes. |
asexual reproduction | reproduction that does not involve the union of gametes and in which a single parent produces offspring that are genetically identical to the parent |
meiosis | a process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, which results in the production of sex cells |
gamete | a haploid reproductive cell that unites another haploid reproductive cell to form a zygote. |
interphase | a period between two mitotic or meiotic divisions during which the cell grows, copies its DNA, and synthesizes proteins. |
cytokinesis | the division of the cytoplasma of a cell; follows the division of the cell's nucleus by mitosis or meiosis. |
prophase | the first stage of mitosis and meiosis in cell division; characterized by the condensation of the chromosomes and the dissolution of the nuclear envelope. |
telophase | the final stage of mitosis or meiosis, during which a nuclear membrane forms around each set of new chromosomes. |
cell plate | the precursor of a new plant cell wall that forms during cell division and divides a cell into two |
spindle fiber | one of the microtubules that extend across a dividing eukaryotic cell; assists in the movement of chromosomes. |
metaphase | one of the stages of mitosis and meiosis, during which all of the chromosomes move to the cell's equator. |
anaphase | a phase of mitosis and meiosis in which the chromosomes separate |
synapsis | the pairing of homologous chromosomes during meiosis. |
tetrad | the four chromatids in a pair of homologous chromosomes that come together as a result of synapsis during meiosis. |
crossing-over | the exchange of genetic material between homologous chromosomes during meiosis; can result in genetic recombination. |
genetic recombination | the regrouping of genes in an offspring that results in a genetic makeup that is different from that of the parents. |
independent assortment | the random distribution of the pairs of genes on different chromosomes to the gametes. |
spermatogenesis | the process by which male gametes form. |
oogenesis | the production, growth, and maturation of an egg, or ovum. |
polar body | a short-lived product of the formation of gametes by meiosis. |
sexual reproduction | reproduction in which gametes from two parents unite. |