Cell Reproduction and the Cell Cycle

Vocabulary practice flashcards covering cell reproduction, genetic organization, the cell cycle, and the stages of mitosis and cytokinesis.

Reasons for Cell Division

The three primary purposes of cell division: reproduction (asexual reproduction in single-celled organisms), growth (developing from a fertilized egg into a multicellular organism), and repair and renewal (replacing cells lost to normal wear and tear or injury).

Nucleus

An organelle that protects DNA and is enclosed by a double membrane known as the nuclear envelope.

Centrioles

A pair of structures found in animal cells that organize microtubules to guide chromosomes during mitosis.

Spindle Fibers

Microtubule structures emerging from centrosomes that attach to and guide chromosomes during mitotic division.

Genome

The complete set of a cell's DNA and genetic information, acting as a complete instruction book on how to make an organism.

Chromatin

The loose, uncoiled form of DNA found in an everyday working cell.

Histones

Positively charged proteins around which DNA wraps to form nucleosomes.

Nucleosome

A structural unit formed when DNA wraps around histones, which tightly winds up to form chromatin.

Chromosome

A condensed form of chromatin prepared for cell division, functioning conceptually as an individual chapter of the genome.

$G_1$ Phase

The stage of interphase characterized by cell growth prior to DNA replication.

$S$ Phase

The synthesis stage of interphase during which the dividing cell duplicates its DNA, creating two identical copies.

$G_2$ Phase

The second gap phase of interphase where the cell undergoes final preparation for mitosis.

Mitosis

The stage of the cell cycle when the cell's nucleus and nuclear material divide.

Prophase

The longest phase of mitosis, during which chromosomes condense and become visible, the nuclear envelope disintegrates, centrosomes move toward opposite poles, and spindle fibers begin to emerge.

Prometaphase

The mitotic stage where chromosomes continue to condense, kinetochores appear at centromeres, and mitotic spindle microtubules attach to kinetochores.

Kinetochores

Protein complexes that appear at the centromeres during prometaphase, serving as points of attachment for mitotic spindle microtubules.

Metaphase

The phase of mitosis in which chromosomes align along the equator of the cell (metaphase plate), with each sister chromatid attached to spindle fibers from opposite poles.

Metaphase Plate

The equatorial plane of the cell along which chromosomes align during metaphase.

Anaphase

The phase of mitosis during which centromeres split in two and sister chromatids (now called chromosomes) are pulled toward opposite poles by shortening microtubules, while certain spindle fibers elongate the cell.

Telophase

The phase of mitosis where chromosomes reach opposite poles and begin to decondense, the nuclear envelope reforms around each set of chromosomes, and the mitotic spindle breaks down.

Cytokinesis

The process that divides the cytoplasm to separate the dividing cell into two distinct daughter cells.

Cleavage Furrow

An indentation that forms at the equator of an animal cell during cytokinesis, which pinches inward until the cell divides into two.

Cell Plate

A structure that forms during plant cell cytokinesis as the precursor to a new cell wall, separating the two daughter cells.