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Definition
the x-shaped, microscopically visible region where crossing over has occurred earlier in prophase 1 between homologous non-sister chromatids
- becomes visible after synapsis ends, with the 2 homologs remaining associated due to sister chromatid cohesion |
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Definition
| a chromosome created when crossing over combines DNA from two parents into a single chromosome |
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| the reproduction of cells |
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| 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. |
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| 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 |
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| a cellular structure carrying genetic material, found in the nucleus of eukaryotic cells |
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| the complex of DNA and proteins that makes up eukaryotic chromosomes |
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| any cell in a multicellular organism except a sperm or egg or their precursors |
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| a haploid reproductive cell, such as an egg or sperm; unite in sexual reproduction to produce a diploid zygote |
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| two copies of a duplicated chromosome attached to each other by proteins at the centromere and sometimes along the arms; make up one chromosome |
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Definition
| 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 |
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Definition
a process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase ad telophase
- conserves chromosome number by allocating replicated chromosomes equally to each of the daughter nuclei |
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Definition
| the division of the cytoplasm to form two seperate daughter cells immediately after mitosis, meiosis 1 or meiosis 2 |
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| the phase of the cell cycle that includes mitosis and cytokinesis |
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Definition
| the first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins |
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Definition
| the synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated |
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Definition
| the second gap, or growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs |
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Definition
| the first stage of mitosis, in which the chromatin condenses into discrete chromosomes visible with a light microscope, the mitotic spindle begins to form, and the nucleolus disappears but the nucleus remains intact |
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Definition
| the second stage of mitosis, in which the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the chromosomes |
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Definition
| the third stage of mitosis, in which the spindle is complete and the chromosomes, attached to the microtubules at their kinetochores, are all aligned at the metaphase plate |
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Definition
| the fourth stage of mitosis, in which the chromatids of each chromosome have separated and the daughter chromosomes are moving to the poles of the cell |
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Definition
| the fifth and final stage if mitosis, in which daughter nuclei are forming and cytokinesis has typically begun |
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Definition
| an assemblage of microtubules and associated proteins that is involved in the movement of chromosomes during mitosis |
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Definition
| a structure present in the cytoplasm of animal cells that functions as a microtubule-organizing center and is important during cell division |
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Definition
| a radial array of short microtubules that extends from each centrosome toward the plasma membrane in an animal cell undergoes mitosis |
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| a structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindle |
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Definition
| an imaginary structure located at a plane midway between the two poles of a cell in metaphase on which the centromeres of all the duplicated chromosomes are located |
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Definition
1 - the process of cytokinesis in animal cells, characterized by pinching of the plasma membrane
2 - the succession of rapid cell divisions without significant growth during early embryonic development that converts the zygote to a ball of cells |
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Definition
| the first sign of cleavage in an animal cell; a shallow groove around the cell in the cell surface near the old metaphase plate |
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Definition
| site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides |
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Definition
a method of asexual reproduction by "division in half"
- in prokaryotes, it does not involve mitosis but in single-celled eukaryotes, mitosis is part of the process |
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Definition
the period in the cell cycle when the cell is not dividing
- cellular metabolic activity is high, chromosomes and organelles are duplicated, and cell size may increase
- often accounts for 90% of cell cycle |
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Definition
| a membrane-bounded, flattened sac located at the midline of a dividing plant cell, inside which the new cell wall forms during cytokinesis |
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| the transmission of traits from one generation to the next |
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| differences among individuals in the composition of their genes or other DNA segments |
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| the scientific study of heredity and hereditary information |
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Definition
| a discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA |
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Definition
| specific place along the length of a chromosome where a given gene is located |
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Definition
the generation of offspring from a single parent that occurs without the fusion of gametes
- offspring are genetically identical in most cases |
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Term
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Definition
1- a linkage of genetically identical individuals or cells
2- in popular usage, an individual that is genetically identical to another individual
3- as a verb, to make one or more genetic replicas of an individual or cell |
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Definition
| a type of reproduction in which two parents give rise to offspring that have unique combinations of genes inherited from both parents via the gametes |
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Definition
| the generation to generation sequence of stages in the reproductive history of an organism |
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Definition
| a display of the chromosome pairs of a cell arranged by size and shape |
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Definition
a pair of chromosomes of the same length, centromere position, and staining pattern that posses genes for the same characters at corresponding loci
- one is inherited from the organism's father and the other from the mother |
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Definition
| a chromosome responsible for determining the sex of an individual |
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Definition
| a chromosome that is not directly involved in determining sex; not a sex chromosome |
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Definition
a cell containing two sets of chromosomes, one set is inherited from each parent
(2n) |
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Definition
a cell containing only one set of chromosomes
(n) |
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Definition
| the union of haploid gametes to produce a diploid |
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Definition
| the diploid cell produced by the union of haploid gametes during fertilization; a fertilized egg |
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Definition
a modified type of cell division in sexually reproducing organisms consisting of two round of cell division but only one round of DNA replication
- results in cells with half the number of chromosome sets as the original cell |
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Term
| Alternation of Generations |
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Definition
a life cycle in which there is both a multicellular diploid form, the sporophyte and a multicellular haploid form, the gametophyte
- characteristic of of plants and some algae |
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Term
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Definition
| the first division of a 2-stage process of cell division in sexually reproducing organisms that results in cells with half the number of chromosome sets as the original cell |
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Definition
| the second division of a 2-stage process of cell division i sexually reproducing organisms that results in cells with half the number of chromosome sets as the original cell |
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Definition
| the pairing and physical connection of duplicated homologous chromosomes during prophase 1 of meiosis |
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Term
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Definition
| the reciprocal exchange of genetic material between non-sister chromatids during prophase 1 of meiosis |
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