Glossary
Apoptosis
Programmed cell death, a normal and controlled process crucial for maintaining cell balance, removing damaged or mutated cells, and essential for development.
Example:
Apoptosis is like a controlled demolition of an old building, precisely removing it to make way for new structures or to prevent collapse.
Apoptosis Genes
Genes that, when active, initiate programmed cell death (apoptosis), a crucial process for removing damaged or unnecessary cells.
Example:
Apoptosis Genes are like the self-destruct sequence in a spy movie, activated to eliminate compromised agents (cells) for the greater good.
Cancerous cells
Cells that have lost the ability to regulate their growth and division, leading to uncontrolled proliferation and the potential to spread throughout the body.
Example:
Cancerous cells are like rogue construction workers who ignore blueprints and safety regulations, building uncontrollably and haphazardly.
Cdk (Cyclin-dependent kinase)
An enzyme that is always present in the cytoplasm and, when activated by cyclin, phosphorylates target proteins to regulate cell cycle progression.
Example:
Cdk is like the car's engine, always present but only active when the right key (cyclin) is inserted and turned.
Cdk-Cyclin complex
A complex formed by the binding of cyclin-dependent kinases (Cdks) and cyclins, which acts as a key regulator and engine that drives the cell cycle progression.
Example:
The Cdk-Cyclin complex is like the ignition key and engine working together to start and drive a car through its journey.
Cell Cycle Checkpoints
Quality control stops during cell division that ensure everything is perfect before the cell moves on, preventing errors like mutations and uncontrolled growth.
Example:
Imagine a car factory where Cell Cycle Checkpoints are inspectors ensuring each car part is perfect before assembly continues, preventing faulty vehicles from leaving the line.
Chromosome Maintenance Genes (telomerase)
Genes, such as telomerase, that are involved in maintaining chromosome integrity, and when active ('ON'), can allow for unlimited cell divisions by preventing telomere shortening.
Example:
Chromosome Maintenance Genes are like the repair crew for shoelace tips (telomeres); if they're always 'ON,' the shoelaces never fray, allowing for endless use.
Cyclin
A protein whose levels fluctuate during the cell cycle, binding to and activating Cdk to trigger specific cell cycle events like mitosis, and then degrading afterward.
Example:
Cyclin is like the fuel gauge in a car; its rising levels indicate readiness to start, and once the journey is complete, its levels drop.
G0 phase
A resting phase that cells enter from the G1 phase if conditions are not favorable for division, or if they are terminally differentiated and no longer divide.
Example:
A neuron enters the G0 phase, like a retired athlete who no longer competes but remains active in other ways.
G1 Checkpoint
A cell cycle checkpoint at the end of the G1 phase that checks if the cell is large enough and has sufficient nutrients and proteins to proceed to DNA synthesis.
Example:
A baker's G1 Checkpoint is ensuring they have enough flour, sugar, and eggs before starting to mix the cake batter.
G1 phase
The first growth phase of the cell cycle where the cell grows and synthesizes proteins and organelles, preparing for DNA replication.
Example:
Before a marathon, a runner enters the G1 phase by ensuring they've eaten enough, hydrated, and stretched adequately before the race begins.
G2 Checkpoint
A cell cycle checkpoint that occurs before mitosis, verifying that DNA replication was completed correctly during the S phase and that there is no DNA damage.
Example:
A librarian's G2 Checkpoint is double-checking that all books have been correctly returned to their shelves after a busy day before closing.
G2 to M transition
The point in the cell cycle where the cell transitions from the second growth phase (G2) into mitosis (M phase), following DNA replication.
Example:
The G2 to M transition is like a pilot's final pre-flight check before taking off, ensuring all systems are ready for the flight.
Growth Promoter Genes
Genes that, when active ('ON'), promote unlimited cell growth and division, and can contribute to cancer if mutated or overexpressed.
Example:
Growth Promoter Genes are like the accelerator pedal in a car; when stuck 'ON,' they cause uncontrolled speed.
M (mitosis) phase
The mitotic phase of the cell cycle during which the cell undergoes nuclear division (mitosis) and cytoplasmic division (cytokinesis) to produce two daughter cells.
Example:
The M (mitosis) phase is like a single parent cell precisely dividing its belongings and then splitting into two identical, independent children.
Metaphase
A stage during mitosis where chromosomes align along the metaphase plate, ensuring they are properly attached to spindle fibers before separation.
Example:
During a synchronized swimming routine, the Metaphase is when all swimmers perfectly align in the center of the pool, ready for the next coordinated movement.
Metaphase Checkpoint
A cell cycle checkpoint during the M phase that ensures all chromosomes are correctly attached to the spindle fibers and aligned at the metaphase plate before sister chromatids separate.
Example:
Before a roller coaster starts, the Metaphase Checkpoint is the final safety check to ensure every passenger is securely buckled into their seat.
Metastasize
The process by which cancerous cells spread from their original site to other parts of the body, forming new tumors.
Example:
When cancer cells metastasize, it's like a small fire spreading from one room to engulf an entire building.
S phase
The synthesis phase of the cell cycle where the cell replicates its entire genome, creating two identical sets of DNA.
Example:
The S phase is like a photocopier making an exact duplicate of an important document before it's distributed.
Touch-Sensor Gene
A gene that, when functioning normally, enables cells to exhibit density-dependent inhibition, stopping division when they come into contact with other cells.
Example:
A Touch-Sensor Gene is like a personal space detector; when it's 'OFF,' cells ignore boundaries and keep crowding together.
Tumor Suppressor Genes
Genes, like p53, that normally inhibit cell division and promote apoptosis, acting as 'stop signs' to prevent uncontrolled cell growth and tumor formation.
Example:
Tumor Suppressor Genes are the brakes in a car; if they fail ('OFF'), the car can't stop, leading to a crash.
p53
A protein that acts as a tumor suppressor, detecting DNA damage, stopping cell division, triggering DNA repair, or initiating apoptosis if damage is irreparable.
Example:
p53 is the cell's vigilant security guard, constantly patrolling for DNA damage and either fixing it or triggering a self-destruct sequence if the damage is too severe.