Chapter 3.4 Flashcards
What is the cell cycle?
The series of changes that a cell undergoes, from the time it forms until it divides
Stages of the cell cycle?
Interphase, Mitosis, and Cytokinesis
What happens during interphase?
The cell grows and maintains its routine functions as well as its contributions to the internal environment
What is interphase divided into?
S, G1, and G2 phase
What occurs during S phase?
Synthesis
What does G1 and G2 stand for?
Stands for Gap or GRowth.
Mitosis occurs in what type of cells?
Somatic, producing two daughter cells from an original cell that are genetically identical
Each new cell from mitosis has a full complement of
46 chromosomes that is typical of humans.
With the 46 chromosomes, there are
2 sets of 23 chromosomes, each inherited from each parent
What is Meiosis?
A second form of cell division that occurs only in the cells that give rise to sex cells (sperm and oocyte).
How many chromosomes in Meosis?
Half the chromosome number, only 23.
Why only 23 chromosomes in Meiosis?
When the sperm fertilizes the egg, the total number of 46 chromosomes is restored
What is Karyokinesis?
This means nuclear movement, and occurs when nuclear contents divide in mitosis
What happens in cytokinesis?
Stands for cell movement, and the cytoplasm is apportioned into the two daughter cells
What occurs during prophase?
Chromatin fibers condense, making the individual chromosomes visible under magnification. Each chromosome consists of two sister chromatics, that are attached by a region on each called a centromere
What do the centrioles do during prophase?
They move to opposite sides of the cell.
What happens to the nuclear envelope during prophase?
The nuclear envelope and nucleolus break apart
What happens in Metaphase?
Spindle fibers attach to the centromeres so that one chromatid attaches to one centromere and a fiber accompanying the other sister chromatic attaches to its centromere
Chromosome location during Metaphase?
Aligned up approximately midway between the centrioles
What occurs during Anaphase?
Centromeres of the chromatids separate and the sister chromatids are now considered individual chromosomes
What occurs in telophase?
Chromosomes complete their migration toward the centrioles. Nuclear envelope forms around each chromosome set and nucleoli become visible within the new nuclei
What is cytokinesis?
Begins during Anaphase when the cell membrane starts to constrict around the middle of the cell. Cleavage furrow continues to tighten throughout telophase and pinches of two cells from one
