Biology Cell Reproduction chapter 8 Modern Biology
Terms in this set (64)
A threadlike, gene-carrying structure found in the nucleus. Consists of one very long DNA molecule and associated proteins.
Cause the DNA to be spread out like spaghetti in a bowl, or tightly condensed into the x-shaped chromosomes. Help maintain the shape of the chromosome and aid in the tight packing of DNA.
negative or neutral proteins; affect gene accessibility, regulate gene expression, and form complexes. Controls specific regions of the DNA.
one of two identical strands into which a chromosome splits during mitosis
Cell structure that joins two sister chromatids of a chromosome.
A single‐celled organism that lacks a membrane‐bound nucleus and specialized organelles.
A type of organism composed of one or more cells containing a membrane‐bound nucleus, specialized organelles in the cytoplasm, and a mitotic nuclear division cycle.
One of the 23 pairs of chromosomes in the human, contains genes that will determine the sex of the individual; human females have two x chromosomes and males have one x and one y chromosome.
All of the other chromosomes in an organism
Chromosomes that have the same sequence of genes, that have the same structure, and that pair during meiosis.
A method of organizing the chromosomes of a cell in relation to number, size, and type.
Term for a full set of chromosomes (46).
Term for a half a set of chromosomes (23).
The process in reproduction and growth by which a cell divides to form daughter cells.
Is the division of a prokaryotic cell into two offspring daughter cell. Consists of three stages: Prokaryotic cell, DNA is copied, Cell begins to divide, and two identical haploid cells form.
Cell process in which the nucleus divides to form two nuclei identical to each other ,and identical to the original nucleus, in a series of steps. Conducted by all eukaryotic cells except sex cells.
A two-stage type of cell division in sexually reproducing organisms that results in cells with half the chromosome number of the original cell.
One full cycle lasts 20 to 24 hours. Gaps occur between its phases. 90% of its life in interphase. G1 = make proteins! S = replicate (12.4 billion nucleotides now). G2 = assemble replicated organelles.
(Mitosis) The phase of the cell cycle that occurs without cell division. During this period the cell produces nutrients and replicates its chromatids. Split into three sub-phases
Mitosis (the division of DNA) and cytokinesis (the division of cytoplasm and other cellular material) occurs
The first growth phase of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.
The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.
The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.
A non-dividing state in which a cell has left the cell cycle.
Chromatin shortens and coils into chromosomes.
An organelle that contains the centriole and is the center of dynamic activity in mitosis
Are located near the nucleus and help to organize cell division.
Fibers that appear during mitosis. Chromosomes attach to the spindle fibers at the centromere and move back and forth between the poles on the fibers.
An assemblage of microtubules and associated proteins that is involved in the movements of chromosomes during mitosis.
attach to the kinetochore and extend to attach each chromatin to a centrosome
A specialized region on the centromere that links each sister chromatid to the mitotic spindle.
The fibers that extend from centromere to centromere during mitosis are
Centromeres of duplicated chromosomes are aligned at plate. Fully formed spindle attach to the sister chromatids from opposite poles
Begins as the centromeres duplicate themselves allowing each one of the chromatids to separate from it's double. These separated chromatids(new chromosomes) move apart and migrate to the opposite poles of the cell
After the chromosome seperates, the cell seals off, Final Phase of Mitosis.
Division of the cytoplasm during cell division
The area of the cell membrane that pinches in and eventually separates the dividing cell
A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis.
DNA coils tightly into chromosomes
The pairing of homologous chromosomes, which does not occur in mitosis.
Each pair of Homologous chromosomes
Portions of chromatids may break off and attach to adjacent chromatids on the homologous chromosome.
Crossing over results in this. This process produces a new mixture of genetic material.
Chromosome centromeres attach to spindle fibers. Homologous chromosomes line up at the equator.
Independent segregation of genes during the formation of gametes
A haploid cell such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote.
The spindles break down, chromosomes uncoil and form two nuclei, and the cell divides.
The original cell produces two new cells.
Begins with two haploid daughter cells which are divided to produce four haploid cells with one set of chromosomes each.
Spindle fibers form and begin to move the chromosomes toward the midline of the dividing cell.
The chromosomes move to the midline of the dividing ell, facing opposite poles of the dividing cell.
The chromatids separate and move toward opposite poles of the cell.
A nuclear membrane forms around the chromosomes in each of the four new cells.
occurs during Telophase 2, resulting in four new cells, each of which contains half of the original cells number of chromosomes.
In the formation of male gametes the original cell produces four sperm cells by meiosis. The production of sperm cells.
In the formation of the egg cells the original cell produces one egg and three polar bodies by meiosis. The egg receives most of the original cells cytoplasm. Production of mature egg cells or ova.
Byproduct of meiosis, cells with little more than DNA that are eventually broken down.
Process by which a single parent reproduces by itself
A reproductive process that involves two parents that combine their genetic material to produce a new organism, which differs from both parents
Two parts of the cell to divide in eukaryote cell division
4 stages of mitosis
How is cell division controlled?
Three check points:
Cell growth checkpoint (G1)
DNA synthesis checkpoint (G2)
Mitosis checkpoint (G3)
When control of cell division is lost, what can occur?
How does crossing over create unique individuals?
The process permits the exchange of genetic material between maternal and paternal chromosomes. A new mixture of genetic material is created.