Cell Biology & Development: Cell Division

Vocabulary practice flashcards covering key terms related to cell division, mitosis, meiosis, cell cycle regulation, and cancer biology.

Binary Fission

The cell division process in prokaryotes involving semi-conservative DNA replication followed by equal division of cytoplasm to generate two daughter cells.

Nucleosome

A structural unit formed by DNA coiling around histone proteins to achieve efficient packaging in eukaryotic cells.

Homologous Chromosomes

Two nearly identical copies of each chromosome present in eukaryotic somatic cells.

Sister Chromatids

Two identical copies of a duplicated chromosome that are joined together by a centromere.

G1 Phase

The main growth phase of the cell cycle that occupies most of a cell's lifetime.

S Phase

The synthesis phase of the cell cycle during which DNA replication occurs.

G2 Phase

The phase of the cell cycle during which organelle replication takes place in preparation for nuclear division.

M Phase

The nuclear division (mitosis) phase of the cell cycle where microtubules separate chromosomes.

C Phase

The cytokinesis phase of the cell cycle during which the cytoplasm divides.

Prophase (Mitosis)

The first phase of mitosis during which chromosomes condense and the mitotic spindle forms.

Metaphase (Mitosis)

The stage of mitosis in which chromosomes align along the central plane of the cell.

Anaphase (Mitosis)

The phase of mitosis in which centromeres divide and chromosomes move toward opposite poles.

Telophase (Mitosis)

The final phase of mitosis where chromosomes uncoil, spindle fibers disappear, and new nuclear envelopes form.

Somatic Cells

Diploid eukaryotic body cells that contain $2n$ chromosomes, where $n$ is the chromosome number.

Germ Cells

Specialized reproductive cells that undergo meiosis to produce haploid gametes containing $n$ chromosomes.

Synapsis

The close junction region during Meiosis I where non-sister homologous chromosomes align to permit crossing-over of chromatids.

Reduction Division

The second division of meiosis (Meiosis II) resulting in non-identical sister chromatids being partitioned into separate haploid cells.

Arm-specific Cohesin

A protein complex that binds the arms of sister chromatids together.

Centromere-specific Cohesin

A protein complex that holds sister chromatids together specifically at the centromere.

G0 Phase

A state of cell cycle arrest at the $G_1$ phase where most non-dividing cells reside until stimulated by external signals such as growth factors.

Cyclin

A regulatory nuclear protein synthesized in response to external signals that binds to CDK to regulate cell cycle progression.

Cyclin Dependent Kinase (CDK)

A nuclear kinase enzyme that only becomes active after binding cyclin, activating downstream enzymes for DNA synthesis and cell division.

Protein Kinase

An enzyme that transfers a phosphate group to a protein (phosphorylation), altering its structure and functional activity.

p53 Protein

A regulatory protein activated by DNA damage that halts the cell cycle, induces DNA repair mechanisms, or triggers apoptosis if damage is unrepairable.

p21 Protein

A CDK inhibitor protein transcribed following p53 activation that binds to Cyclin/CDK complexes to inhibit DNA synthesis initiation.

Apoptosis

Programmed cell death triggered when cellular DNA damage is beyond repair.

Metastasis

The process by which malignant cancer cells spread from a primary site to other tissues throughout the body.