The Cell Cycle – Campbell Biology Ch. 12

Vocabulary flashcards summarizing essential terms and definitions from the Campbell Biology lecture on the cell cycle.

Cell Division

The process by which a parent cell divides to form two or more daughter cells; enables reproduction, growth, and repair.

Cell Cycle

The ordered sequence of events from a cell’s formation to its own division, consisting of interphase and the mitotic (M) phase.

Genome

All the DNA contained in one cell; may be a single DNA molecule (prokaryotes) or multiple molecules (eukaryotes).

Chromosome

A DNA molecule packaged with proteins; carries genetic information and becomes highly condensed during division.

Chromatin

The complex of DNA and associated proteins that makes up eukaryotic chromosomes; condenses during mitosis.

Somatic Cell

Any non-reproductive cell in a multicellular organism; contains two sets of chromosomes.

Gamete

Reproductive cell (sperm or egg) containing half the number of chromosomes of a somatic cell.

Sister Chromatids

Identical copies of a duplicated chromosome joined together by cohesins at the centromere.

Centromere

The constricted region of a duplicated chromosome where sister chromatids are most closely attached.

Mitosis

Division of the nucleus in eukaryotic cells, producing genetically identical daughter nuclei.

Cytokinesis

Division of the cytoplasm, producing two separate daughter cells after mitosis.

Meiosis

Special type of cell division that reduces chromosome number by half, forming non-identical gametes.

Interphase

Phase of the cell cycle (≈90 %) that includes cell growth and DNA replication (G1, S, and G2).

G1 Phase

The first ‘gap’ of interphase; cell grows and performs normal functions.

S Phase

‘Synthesis’ phase of interphase; DNA is replicated and chromosomes are duplicated.

G2 Phase

Second ‘gap’ phase; cell grows and prepares for mitosis by producing proteins and organelles.

Prophase

First stage of mitosis; chromatin condenses, nucleolus disappears, and mitotic spindle begins to form.

Prometaphase

Mitotic stage in which the nuclear envelope fragments and spindle microtubules attach to kinetochores.

Metaphase

Stage of mitosis where chromosomes align at the metaphase plate midway between spindle poles.

Anaphase

Mitotic stage in which sister chromatids separate and move toward opposite poles of the cell.

Telophase

Final stage of mitosis; daughter nuclei form, chromosomes decondense, and nuclear envelopes reassemble.

Mitotic Spindle

Structure of microtubules and associated proteins that orchestrates chromosome movement during mitosis.

Centrosome

Microtubule-organizing center in animal cells; duplicates during interphase to form spindle poles.

Aster

Radial array of short microtubules extending from each centrosome during mitosis.

Kinetochore

Protein complex on the centromere where spindle microtubules attach to move chromosomes.

Metaphase Plate

Imaginary plane equidistant between spindle poles where chromosomes line up during metaphase.

Separase

Enzyme that cleaves cohesins, allowing sister chromatids to separate at anaphase.

Nonkinetochore Microtubules

Spindle fibers that do not attach to kinetochores but overlap and elongate the cell during anaphase.

Cleavage Furrow

Contractile ring indentation that pinches an animal cell in two during cytokinesis.

Cell Plate

Structure formed by coalescing vesicles in plant cells that develops into a new cell wall during cytokinesis.

Binary Fission

Method of asexual reproduction in prokaryotes; chromosome replicates and the cell splits in two.

Origin of Replication

Specific site where bacterial chromosome replication begins during binary fission.

Cyclin

Regulatory protein whose concentration fluctuates during the cell cycle and activates Cdks.

Cyclin-Dependent Kinase (Cdk)

Enzyme that phosphorylates target proteins only when bound to a cyclin; drives cell-cycle events.

MPF (Maturation-Promoting Factor)

Cyclin-Cdk complex that triggers a cell’s passage from G2 into the M phase.

Checkpoint

Control point in the cell cycle where stop-and-go signals regulate progression (e.g., G1, G2, M).

G0 Phase

Non-dividing state a cell enters if it does not receive a go-ahead signal at the G1 checkpoint.

Growth Factor

External signaling molecule that stimulates cell division in target cells.

Platelet-Derived Growth Factor (PDGF)

Growth factor released by platelets that triggers fibroblast division during wound healing.

Density-Dependent Inhibition

Phenomenon in which crowded cells stop dividing when they contact neighbors.

Anchorage Dependence

Requirement that a cell be attached to a substratum in order to divide; lost in cancer cells.

Transformation

Process that converts a normal cell into a cancer cell.

Tumor

Mass of abnormal cells resulting from uncontrolled cell division.

Benign Tumor

Non-invasive tumor whose cells remain at the original site.

Malignant Tumor

Invasive tumor that can impair organ function and give rise to metastases.

Metastasis

Spread of cancer cells to distant locations, forming secondary tumors.

Chemotherapy

Cancer treatment that uses drugs to target dividing cells, often by disrupting the cell cycle.