Cell Communication
What is cell communication?
Cell communication is the process by which cells send, receive, and respond to signals.
What are the three main stages of cell signaling?
Reception, transduction, and response.
What is the function of a receptor protein?
A receptor protein recognizes and binds to a specific signaling molecule, allowing a cell to receive and respond to a signal.
What is homeostasis?
Homeostasis is the maintenance of stable internal conditions within an organism.
What are the three stages of interphase?
G1, S, and G2.
What is the difference between autocrine, paracrine, and synaptic signaling?
Autocrine: A cell releases a signal that binds to receptors on itself.
Paracrine: A cell releases signals that affect nearby cells.
Synaptic Signaling: A cell that releases a signal to the adjacent cell.
What happens during the reception stage?
A signaling molecule binds to a specific receptor on the cell membrane or inside the cell.
Where are intracellular receptors located?
Intracellular receptors are located inside the cell, usually in the cytoplasm or nucleus.
What is negative feedback?
Negative feedback is a mechanism that reverses a change in a system to bring conditions back toward a set point.
During which stage of the cell cycle does DNA replication occur?
S phase
What is a ligand?
A ligand is a signaling molecule that binds to a specific receptor.
What enzyme adds phosphate groups to proteins during cell signaling?
Protein kinase
What type of signaling molecules can pass through the cell membrane and bind to intracellular receptors?
Small, nonpolar molecules
What is positive feedback?
Positive feedback is a mechanism that strengthens or amplifies an initial change.
What are the four main stages of mitosis in the correct order?
Prophase, metaphase, anaphase, and telophase.
Why can only certain cells respond to a specific signaling molecule?
Only cells that have the correct receptor for that signaling molecule can respond to it.
What is signal amplification, and why is it important?
Signal amplification occurs when one signaling molecule activates many molecules within a signaling pathway, increasing the strength of the original signal.
What is the difference between intracellular and membrane receptors?
Intracellular receptors are located inside the cell and bind to signaling molecules that can cross the membrane. On the other hand, membrane receptors are located on the cell membrane and bind to signaling molecules that generally cannot pass through the membrane.
How does insulin help regulate blood glucose levels through negative feedback?
When blood glucose levels increase, the pancreas releases insulin. Insulin causes body cells to take up more glucose and promotes glucose storage, lowering blood glucose levels.
What is the purpose of cell cycle checkpoints?
Cell cycle checkpoints ensure that the cell is ready to move to the next stage and that important processes have been completed correctly.
How can the same signaling molecule cause different responses in different target cells?
Different target cells may have different receptors and signaling proteins, causing them to produce different responses to the same signaling molecule.
How does a G protein-coupled receptor transmit a signal inside a cell?
A signaling molecule binds to the G protein-coupled receptor, causing it to activate a G protein. The activated G protein then interacts with another protein to continue the signaling pathway.
How can a signaling pathway cause changes in gene expression?
A signaling pathway can activate transcription factors, which bind to DNA and increase or decrease the transcription of specific genes.
Why does positive feedback amplify a response instead of reversing the original stimulus? Give an example.
Positive feedback amplifies the original stimulus because the response creates an even stronger stimulus, causing the process to continue. An example is childbirth.
How can mutations in genes that regulate the cell cycle lead to cancer?
Mutations in cell cycle regulatory genes can cause cells to divide uncontrollably, potentially resulting in cancer.