Category: Lab Notes: Cell Biology

The S phase is the period of the cell cycle in which DNA is replicated, producing identical copies of the genome for distribution to daughter cells. It is tightly regulated to maintain accuracy and prevent genomic instability.

Genomic instability describes the increased tendency of cells to accumulate genetic alterations due to failures in DNA repair, replication fidelity, and chromosome segregation. It plays a central role in cancer development, ageing, and hereditary disorders.

The G₂ phase is the period after DNA replication during which the cell checks for errors, repairs damage, and prepares for mitosis. It is essential for accurate chromosome segregation and genomic stability.

Terminally differentiated cells are highly specialized cells that have undergone a differentiation program and generally withdraw permanently from productive cell division. This article explains the molecular mechanisms of terminal differentiation, its relationship with cell-cycle exit, and the differences between terminal differentiation, quiescence, and cellular senescence.

Cellular quiescence is a reversible non-proliferative state in which cells temporarily withdraw from the active cell cycle while remaining viable and metabolically active. This article explores the molecular mechanisms regulating quiescence, its relationship with the G₀ phase, cell-cycle re-entry, stem-cell maintenance, metabolism, transcription, and cellular quality control, as well as its distinction from senescence and terminal differentiation.

The ubiquitin-proteasome system is the master regulator of the cell cycle, controlling cyclin degradation, checkpoint progression, and mitotic exit. This comprehensive guide covers UPS mechanisms in G1/S transition, S phase, mitosis, and cancer therapy.

Cell division is a tightly regulated process through which one cell produces two daughter cells. It underpins growth, development, and tissue maintenance, relying on accurate DNA replication, mitosis, and cytokinesis. Errors in cell division can lead to genomic instability and disease.

The autophagy-lysosome pathway is the cell’s primary degradation and recycling system, responsible for clearing damaged proteins, dysfunctional organelles, and intracellular pathogens. Dysfunction in this pathway has been linked to neurodegenerative disorders, cancer, and metabolic syndromes. This article explores how the process works, its role in disease prevention, and emerging therapeutic strategies targeting this vital cellular mechanism.

SYCP2 is a meiosis‑specific protein that forms the lateral elements of the synaptonemal complex. Its interaction with SYCP3 is essential for chromosome pairing, recombination, and fertility.

SYCP1 is a meiosis‑specific protein that forms the transverse filaments of the synaptonemal complex. Its correct assembly is essential for homologous chromosome pairing, recombination, and fertility.

Meiosis is the specialised cell division that produces haploid gametes and ensures genetic diversity. This article explains its stages, chromosome behaviour, and importance in reproduction.

SYCP3 is a meiosis‑specific protein essential for chromosomal synapsis and the formation of the synaptonemal complex. Mutations in SYCP3 are linked to meiotic arrest, infertility, and genomic instability.

The synaptonemal complex is a meiosis‑specific protein structure essential for homologous chromosome pairing, recombination, and fertility. Its disruption leads to meiotic arrest, aneuploidy, and reproductive disorders.

The 20S proteasome is the catalytic core of the proteasome system, responsible for ATP‑independent degradation of damaged proteins. This article explains its structure, mechanism, and roles in cellular regulation.

Protein degradation is a vital cellular process that removes damaged or unnecessary proteins to maintain homeostasis. This article explains the ubiquitin–proteasome system, autophagy, and their roles in cellular regulation and disease.