BIOL 151 Lecture: Cellular Division, Differentiation, and Signal Transduction Dynamics

Flashcards covering key vocabulary from the BIOL 151 lecture on cellular division, differentiation, and signal transduction dynamics, including terms related to cell structure, stem cells, signaling pathways, kinases, phosphatases, and protein degradation.

Signal Transduction

The process by which a signal is transmitted from the exterior to the interior of a cell, often involving multiple steps in a pathway.

Cell Membrane

A plasma membrane that acts as a barrier between the inside and outside of a cell, present in all cells.

Cell Receptors

Proteins located on the cell surface that receive information from other cells by binding to specific signaling molecules.

Stem Cells

Cells that receive signals regulating self-renewal cell divisions and can differentiate into various cell types.

Self-renewal Cell Division

A type of asymmetrical cell division where one daughter cell remains a stem cell while the other becomes a transit amplifying cell.

Asymmetrical Cell Division

A process where a stem cell divides to produce one daughter cell that remains a stem cell and another that becomes a transit amplifying cell.

Transit Amplifying Cells

Cells produced from stem cell division that undergo rapid division to generate a population of partially mature cells before differentiating into a mature cell type.

Differentiation

The process by which a cell becomes specialized in structure and function, typically leading to a mature cell type that rarely divides again.

Adult Stem Cells

Stem cells that are pluripotent, meaning they are capable of differentiating into a limited set of cell types within the body.

Pluripotent

The characteristic of adult stem cells to differentiate into a limited range of specialized cell types.

Signaling Molecule (Ligand)

Molecules released by some cells that bind to and activate receptors on other cells, initiating a signaling pathway.

Protein Kinase

An enzyme that phosphorylates target proteins by transferring phosphates from ATP, creating a strong, covalent chemical bond.

Protein Phosphatase

An enzyme that removes phosphate groups from proteins by cutting the phosphate bond, effectively de-activating the protein.

Phosphorylation

The robust chemical process of adding a phosphate group to a protein, typically altering its activity or function.

Kinase Cascade Signaling Pathway

A multi-step signaling pathway where activated receptor subunits lead to sequential phosphorylation and activation of intracellular kinases (like TK1, TK2) and transcription factors (TFa), ultimately affecting gene expression.

Positive Feedback Loop (in signaling)

A mechanism in a signaling pathway where the activation or generation of a new kinase by the pathway targets and activates an upstream element, keeping the pathway active even if the initial signal is removed.

Protein Turnover

The continuous process in a cell where existing proteins are destroyed, and new proteins are synthesized to replace them.

Ubiquitin-dependent Proteolysis

A highly regulated process where ubiquitin is selectively attached to proteins destined for destruction, which are then moved to the proteasome and degraded.

Proteasome

A large protein complex responsible for destroying ubiquitinated proteins within the cell as part of protein turnover and regulation.

E3 Ubiquitin Ligases

Enzymes that transfer ubiquitin to specific target proteins, marking them for destruction by the proteasome.

De-Ubiquitinases (DUBs)

Enzymes that remove ubiquitin from proteins, thereby preventing their degradation or regulating their activity.