3. Chromosome Transmission During Cell Division and Sexual Reproduction Flashcards
The structures within living cells that contain the genetic material
Chromosome
The complex of DNA and proteins that is found within eukaryotic chromosomes.
Chromatin
Bacteria and Archaea. The term refers to the observation that their chromosomes are not contained within a separate nucleus in the cell.
Prokaryotes
A darkly staining region that contains the genetic material of mitochondria, chloroplasts, or bacteria.
Nucleoid
One of the three domains of life. A defining feature of these organisms is that their cells contain a membrane-bound nucleus.
Eukaryotes
A specialized structure within a cell that is surrounded by a single or double membrane.
Organelle
A membrane-bound organelle in eukaryotic cells where the chromosomes are found.
Nucleus
The field of genetics that involves the microscopic examination of chromosomes.
Cytogenetics
A scientist who studies chromosomes under the microscope.
Cytogeneticist
Any cell of the body except for gametes and germ-line cells that give rise to gametes.
Somatic Cell
A reproductive cell (usually haploid) that can unite with another reproductive cell to create a zygote. Sperm and egg cells.
Gamete (Germ Cells)
A photographic representation of all the chromosomes within a cell. It reveals how many chromosomes are found within an actively dividing somatic cell.
Karyotype
An organism or cell that contains two sets of chromosomes.
Diploid
Structures that are similar to each other due to descent from a common ancestor.
Homologs
An alternative form of a specific gene.
Allele
The physical location of a gene or other DNA segment within a chromosome.
Locus (Loci)
A form of reproduction that does not involve the union of gametes; at the cellular level, a preexisting cell divides to produce two new cells.
Asexual Reproduction
Consisting of more than one cell.
Multicellularity
The physical process whereby a bacterial cell divides into two daughter cells. During this event, the two daughter cells become separated by the formation of a septum.
Binary Fission
In eukaryotic cells, a series of stages through which a cell progresses in order to divide. The phases are G for gap, S for synthesis (of the genetic material), and M for mitosis (which includes cytokinesis). There are two G phases, G1 and G2.
Cell Cycle
The series of phases G1, S, and G2, during which a eukaryotic cell spends most of its life.
Interphase
A point in the G1 phase of the cell cycle at which a cell becomes committed to progress to cell division.
Restriction Point
Following chromosomal replication in eukaryotes, the two copies that remain attached to each other
Chromatids
Pairs of replicated identical chromosomes that are attached to each other at the centromere.
Sister Chromatids (Dyad)
A segment of a eukaryotic chromosome that provides an attachment site for the kinetochore.
Centromere
A single chromatid within a dyad.
Monad
A group of proteins that attach to the centromere during meiosis and mitosis.
Kinetochore
A type of nuclear division into two nuclei, during which each daughter cell receives the same complement of chromosomes.
Mitosis
During cell division in eukaryotic cells, a structure is composed of microtubules that sorts the chromosomes.
Mitotic Spindle Apparatus
A structure in a eukaryotic cell from which microtubules grow.
Microtubule-Organizing Center (MTOC)
A cellular structure from which microtubules emanate.
Centrosome
During cell division in eukaryotes, one of two sites in the cell where microtubules originate.
Spindle Pole
A pair of structures within each centrosome of animal cells.
Centrioles
The microtubules that emanate outward from the centrosome toward the plasma membrane.
Astral Microtubules
The microtubules that project toward the region where the chromosomes will be found during mitosis; they overlap each other and play a role in pushing the spindle poles apart.
Polar Microtubules
The microtubules that are connected to kinetochores on chromosomes.
Kinetochore Microtubules
The first phase of mitosis. The chromosomes have already replicated and begin to condense. The mitotic spindle apparatus starts to form.
Prophase
The second phase of mitosis. During this phase, the nuclear membrane vesiculates, and the mitotic spindle is completely formed.
Prometaphase
The plane along which pairs of sister chromatids align during metaphase.
Metaphase Plate
The third phase of mitosis. The chromosomes align along the central plane of the spindle apparatus, and the formation of the spindle is completed.
Metaphase
The fourth phase of mitosis. As anaphase proceeds, half of the chromosomes move to one pole, and the other half move to the other pole.
Anaphase
The fifth stage of mitosis. The chromosomes have reached their respective poles and decondense.
Telophase
The division of a single cell into two cells. The two nuclei produced in mitosis are segregated into separate daughter cells during cytokinesis.
Cytokinesis
A constriction that causes the division of an animal cell into two cells during cytokinesis.
Cleavage Furrow
The structure that forms between two daughter plant cells and leads to the separation of the cells by the formation of an intervening cell wall.
Cell Plate
A form of nuclear division in which the sorting process results in the production of haploid cells from a diploid cell.
Meiosis
Refers to a cell that contains half the genetic material found in somatic cells. For a species that is diploid, a haploid gamete contains a single set of chromosomes.
Haploid
The first stage of prophase of meiosis I.
Leptotene
The second stage of prophase of meiosis I.
Zygotene
The event in which homologous chromosomes recognize each other and then align themselves along their entire lengths.
Synapsis
The third stage of prophase of meiosis I.
Pachytene
A structure in which two pairs of homologous sister chromatids have synapsed (i.e., aligned) with each other.
Bivalent (Tetrad)
A physical exchange of pieces between homologous chromosomes that most commonly occurs during prophase of meiosis I.
Crossing Over
The site where crossing over occurs between two chromosomes.
Chiasma (Chiasmata)
The fourth stage of prophase of meiosis I.
Diplotene
The fifth stage of prophase of meiosis I.
Diakinesis
The process whereby parents make gametes (e.g., sperm and egg) that fuse with each other in the process of fertilization to begin the life of a new organism.
Sexual Reproduction
The production of gametes (e.g., sperm or egg cells).
Gametogenesis
Describes a species that produces morphologically similar gametes.
Isogamous
Describes a species that produces two morphologically different types of gametes.
Heterogamous
A male gamete that are small and usually travel relatively far distances to reach the female gamete.
Sperm Cell
A female gamete that is usually very large and nonmotile.
Egg Cell (Ovum)
The production of sperm cells.
Spermatogenesis
The production of egg cells.
Oogenesis
