Cell Cycle, Mitosis, and Stem Cell Differentiation

Vocabulary practice flashcards covering cell cycle phases, mitosis stages, cellular organelles, checkpoint regulation, and stem cell differentiation principles.

DNA Replication

The essential biological process occurring prior to cell division that ensures all resulting daughter body cells in a multicellular organism inherit the exact same genetic information.

Centrioles and Microtubules

Cellular structures that organize spindle apparatus during division; disruption prevents proper separation of chromosomes, resulting in cells with twice the normal chromosome number.

Metaphase

The stage of mitosis where chromosomes align linearly down the equatorial plate in the middle of the cell, positioning chromatids for proper separation to opposite poles.

Anaphase

The mitotic stage in which sister chromatids are pulled apart and migrate along spindle fibers toward opposite poles of the dividing cell.

Cell Plate

A dividing structure that forms down the center of dividing plant cells during cytokinesis to separate the parent cell into two daughter cells.

Cell Cycle

The cyclical sequence of cellular growth and replication comprising interphase ($G_1$, $S$, and $G_2$ phases) followed by the mitotic ($M$) phase and cytokinesis.

Interphase

The major portion of the cell cycle during which cells perform normal metabolic roles, grow, and replicate their DNA before entering mitosis.

$S$ Phase

The synthesis stage of interphase during which DNA replication occurs, doubling the amount of DNA from the initial amount present in the $G_1$ phase.

$G_1$ Phase

The first growth phase of interphase during which the cell grows, increases organelle count, and performs normal metabolic roles before DNA replication.

$G_2$ Phase

The second growth phase of interphase following DNA replication where the cell continues growing and makes preparations for mitosis.

Helicase

An enzyme responsible for unwinding and separating the double strands of DNA; a defect in helicase halts DNA replication during the $S$ phase.

Spindle Fibers

Protein filaments of the mitotic spindle that guide chromosome alignment and chromatid separation; failure of these fibers prevents equal distribution of chromosomes to daughter cells.

Cell Differentiation

The developmental process by which unspecialized stem cells acquire specific structures and functions through selective activation and expression of genes.

Differential Gene Expression

The regulation of gene activity wherein genetically identical cells express distinct subsets of genes, enabling specialized forms and functions across tissues.

Stem Cells

Undifferentiated cells capable of continuous self-renewal via cell division and possessing the potential to differentiate into specialized cell types.

Adult Stem Cells

Partially committed stem cells found in the body after birth (such as neural, epithelial, mesenchymal, hematopoietic, and muscle stem cells) that repair and maintain specific tissues.

Embryonic Stem Cells

Pluripotent cells derived before birth from the inner cell mass of a blastocyst that can develop into nearly any specialized cell type in the body.

Inner Cell Mass

The localized cluster of cells within a blastocyst that gives rise to embryonic stem cells and can be cultured to undergo targeted differentiation.

Germ Layer Differentiation

The process where embryonic stem cells diversify into the three primary germ layers: ectoderm (outer body layer), mesoderm (middle body layer), and endoderm (inner body layer).

Ectoderm

The embryonic germ layer that composes the outer layer of the body.

Mesoderm

The embryonic germ layer that composes the middle layer of the body.

Endoderm

The embryonic germ layer that composes the inner layer of the body.

Checkpoint Genes

Genes that encode regulatory proteins that monitor and control progression through stages of the cell cycle to prevent inappropriate cell division.

Tumor

A mass of abnormally dividing cells that forms when cell cycle regulation fails, often due to un-repaired DNA damage or mutations in proto-oncogenes.

Colchicine

A mitotic inhibitor used in cell cycle studies that prevents spindle fiber formation, causing an accumulation of cells arrested in prophase.

Shoot Apical Cells

Actively dividing plant meristematic cells located at the tips of shoots responsible for primary plant growth.

Myosin and Crystallins

Examples of tissue-specific proteins produced via differential gene activation: myosin is synthesized in contractile muscle cells, whereas crystallins are uniquely synthesized in lens cells.