Unit 5: Cell Division Flashcards
growth and death of a cell
cell cycle
the resting phase between successive mitotic divisions of a cell, or between the first and second divisions of meiosis.
interphase
the period in the cell cycle from the end of cell division to the beginning of DNA replication
G1
the period in the cell cycle from the completion of DNA replication to the beginning of cell division
G2
A structure found inside the nucleus of a cell. Is made up of proteins and DNA organized into genes. Each cell normally contains 23 pairs.
chromosome
is one of the two identical halves of a chromosome that has been replicated in preparation for cell division.
A chromatid
appears as a constricted region of a chromosome and plays a key role in helping the cell divide up its DNA during division (mitosis and meiosis). Specifically, it is the region where the cell’s spindle fibers attach.
centromere
Two chromosomes in a pair – normally one inherited from the mother and one from the father
homologous chromosomes
A type of protein found in chromosomes. Histones bind to DNA, help give chromosomes their shape, and help control the activity of genes.
histones
either of the two identical chromatids that are formed by replication of a chromosome during the S phase of the cell cycle, are joined by a centromere, and segregate into separate daughter cells during anaphase.
sister chromatids
the first stage of cell division, before metaphase, during which the chromosomes become visible as paired chromatids and the nuclear envelope disappears. The first prophase of meiosis includes the reduction division.
prophase
the second stage of cell division, between prophase and anaphase, during which the chromosomes become attached to the spindle fibers.
metaphase
the stage of mitosis after the process of metaphase, when replicated chromosomes are split and the newly-copied chromosomes are moved to opposite poles of the cell.
anaphase
the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed.
telophase
involves one parent and produces offspring that are genetically identical to each other and to the parent.
asexual reproduction
refers to the presence of a single set of chromosomes in an organism’s cells. Sexually reproducing organisms are diploid (having two sets of chromosomes, one from each parent). In humans, only the egg and sperm cells are haploid
haploid
term that refers to the presence of two complete sets of chromosomes in an organism’s cells, with each parent contributing a chromosome to each pair. Humans are, and most of the body’s cells contain 23 chromosomes pairs.
diploid
essentially the crossing over and recombination of genetic material between non sister chromatids
prophase I
The second stage in the first meiotic division after prophase I, and highlights the alignment of paired homologous chromosomes along a single plane in the center of the cell.
metaphase I
The third stage in the first meiotic division after prophase I, and highlights the separation of paired homologous chromosomes towards opposite ends of the cell
anaphase I
the final stage of mitosis and of the second division of meiosis in which the spindle disappears and the nucleus reforms around each set of chromosomes.
telophase I
is the phase that follows after meiosis I, or after interkinesis if present. If interkinesis takes place, the nuclear envelope and the nucleolus disintegrate during this. The chromosomes are condensed. The centrosomes replicate and move towards the opposite poles
Prophase II
is the second stage in meiosis II. It follows prophase II, which primarily highlights the condensation of the chromosomes and the movement of centrosomes to polar regions of the cell.
metaphase II
the stage when sister chromatids of every chromosome separate and begin to move towards the opposite ends of the cell.
Anaphase II
The stage in meiosis II after anaphase II, and identified by the complete movement and separation of the chromosomes to the opposite ends of the cell.
telophase II
the first stage in the meiotic division or the reduction division of the meiosis.
Meiosis I
is a mitotic division of each of the haploid cells produced in meiosis I. During prophase II, the chromosomes condense, and a new set of spindle fibers forms. The chromosomes begin moving toward the equator of the cell.
Meiosis II
a mature haploid male or female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote.
gamete
