Unit 4: Cell Communication and Cell Cycle Flashcards
Signal transduction pathway
A series of molecular events and chemical reactions that lead to a cellular response, triggered by a signal
Receptor
A protein that detects a signal molecule and performs an action in response
Ligand
A molecule that binds specifically to another molecule, usually a larger one, like a receptor
Second messenger
Small, non-protein molecules that relay signals inside the cell after activation by a receptor
Feedback loop
A system where the output of a pathway regulates that same pathway; can be positive or negative
Positive feedback
A mechanism that amplifies a change away from equilibrium
Negative feedback
A mechanism that reverses a change to maintain equilibrium or homeostasis
Cell cycle
The series of events that cells go through as they grow and divide
Interphase
The phase of the cell cycle during which the cell grows, replicates DNA, and prepares for mitosis
Mitosis
The division of the nucleus into two genetically identical daughter nuclei
Cytokinesis
The division of the cytoplasm to form two separate daughter cells after mitosis
Checkpoints
Control points in the cell cycle where stop and go-ahead signals regulate the cycle
Cyclins
Proteins that regulate the timing of the cell cycle in eukaryotic cells
CDKs (Cyclin-dependent kinases)
Enzymes that activate or inactivate other proteins by phosphorylating them, regulated by cyclins
Cancer
A disease in which cells divide uncontrollably and invade other tissues due to loss of cell cycle control
Apoptosis
Programmed cell death that occurs in multicellular organisms as a controlled part of development or stress response
