1.
alternation of generations: A life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants and some algae.
2.
asexual reproduction: The generation of offspring from a single parent that occurs without the fusion of gametes (by budding, division of a single cell, or division of the entire organism into two or more parts). In most cases, the offspring are genetically identical to the parent.
3.
autosomes: A chromosome that is not directly involved in determining sex; not a sex chromosome.
4.
binary fission: A method of asexual reproduction by "division in half." In prokaryotes, it does not involve mitosis, but in single-celled eukaryotes that undergo this, mitosis is part of the process.
5.
cell cycle: An ordered sequence of events in the life of a cell, from its origin in the division of a parent cell until its own division into two. The eukaryotic is composed of interphase (including GG1, S, and GG2 subphases) and M phase (including mitosis and cytokinesis).
6.
centromere: in a duplicated chromosome, the region on each sister chromatid where they are most closely attached to each other by proteins that bind to specific DNA sequences; this close attachment causes a constriction in the condensed chromosome.
7.
chiasmata: The X-shaped, microscopically visible region where crossing over has occurred earlier in prophase I between homologous nonsister chromatids. they become visible after synapsis ends, with the two homologs remaining associated due to sister chromatid cohesion.
8.
chromatin: The complex of DNA and proteins that makes up eukaryotic chromosomes. When the cell is not dividing, it exists in its dispersed form, as a mass of very long, thin fibers that are not visible with a light microscope.
9.
crossing over: The reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosis.
10.
cytokinesis: The division of the cytoplasm to form two separate daughter cells immediately after mitosis, meiosis I, or meiosis II.
11.
density dependent inhibition: The phenomenon observed in normal animal cells that causes them to stop dividing when they come into contact with one another.
12.
diploid: A cell containing two sets of chromosomes (2n), one set inherited from each parent.
13.
G1 phase: The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.
14.
G2 phase: The second gap, or growth phase, of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.
15.
gametes: A haploid reproductive cell, such as an egg or sperm. unite during sexual reproduction to produce a diploid zygote.
16.
gametophyte: In organisms (plants and some algae) that have alternation of generations, the multicellular haploid form that produces haploid gametes by mitosis. The haploid gametes unite and develop into sporophytes.
17.
gene locus: specific location of a gene on a chromosome
18.
genome: The genetic material of an organism or virus; the complete complement of an organism's or virus's genes along with its noncoding nucleic acid sequences.
19.
haploid: A cell containing only one set of chromosomes (n).
20.
homologous chromosomes: A pair of chromosomes of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. One is inherited from the organism's father, the other from the mother.
21.
interphase: The period in the cell cycle when the cell is not dividing. During this phase, cellular metabolic activity is high, chromosomes and organelles are duplicated, and cell size may increase. often accounts for about 90% of the cell cycle.
22.
karyotype: A display of the chromosome pairs of a cell arranged by size and shape.
23.
kinetochore: A structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindle.
24.
meiosis: A modified type of cell division in sexually reproducing organisms consisting of two rounds of cell division but only one round of DNA replication. It results in cells with half the number of chromosome sets as the original cell.
25.
metastasis: The spread of cancer cells to locations distant from their original site.
26.
mitosis: A process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase. conserves chromosome number by allocating replicated chromosomes equally to each of the daughter nuclei.
27.
S phase: The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.
28.
sex chromosomes: A chromosome responsible for determining the sex of an individual.
29.
somatic cells: Any cell in a multicellular organism except a sperm or egg or their precursors.
30.
sporophyte: In organisms (plants and some algae) that have alternation of generations, the multicellular diploid form that results from the union of gametes. it produces haploid spores by meiosis that develop into gametophytes.
31.
synapsis: The pairing and physical connection of duplicated homologous chromosomes during prophase I of meiosis.
32.
zygote: The diploid cell produced by the union of haploid gametes during fertilization; a fertilized egg
