Lecture 5

Cell Cycle

Repeating pattern of cell growth and division, involving nuclear division to produce genetically identical daughter cells, with DNA replication occurring between cell divisions.

Interphase

Cell cycle phase consisting of G1 phase (cell growth), S phase (DNA replication), and G2 phase (cell growth and protein synthesis for mitosis).

Terminally Differentiated Cells

Cells that have stopped dividing and are arrested in G0 phase, such as mature neurons.

Centrosome

Microtubule organizing center near the nuclear envelope, containing centrioles and surrounded by pericentriolar material.

M Phase

Cell cycle phase encompassing mitosis (nuclear division) and cytokinesis (cell division), with stages like prophase, prometaphase, metaphase, anaphase, and telophase.

Cytokinesis

Process of cytoplasm division, involving the formation of a cleavage furrow in animal cells and a cell plate in plant cells.

Syncytium

Multi-nucleated cells resulting from mitosis without cytokinesis, common in early development or specific cases like Drosophila embryos.

Cell Cycle Checkpoints

Control points in the cell cycle where sensor proteins detect abnormalities or damage, leading to temporary cell cycle stops for repair or triggering apoptosis, senescence, or uncontrolled growth (cancerous).

Somatic Cells

Cells in an organism that are either in G0 phase or actively undergoing mitosis.

Meiosis

Cell division process resulting in four haploid daughter cells, involving two rounds of division (Meiosis I and Meiosis II) with crossing over and genetic recombination.