Cell Communication & Introduction to Signal Transduction
What are the 3 ways cells communicate
Direct Contact, Local Signaling, Long-distance Signaling
What is gene expression
Gene expression is when the instructions of our DNA are converted into a product
What is homeostasis?
The state of relatively stable internal conditions. Organisms can detect and respond to the stimulus
What are the three stages of interphase?
G1, S, G2
What is the function of the G1 checkpoint?
Check for cell size, growth factors, and DNA damage. It has a stop/go signal. “Go”- cell completes the whole cell cycle. “Stop”- cell enters a non-dividing state known as the G0 phase
What is Juxtacrine
Direct Signaling
How can signal transduction pathways affect gene expression
They can alter the amount of product being produced
How does cell signaling maintain homeostasis?
Cells in multicellular organisms must be able to communicate and this communication occurs through signal transduction.
What are the 4 phases of mitosis?
Prophase, metaphase, anaphase, telophase
What is the function of Cyclins and how do they do it
Cyclins regulate cell cycle. Cyclins are synthesized and degraded at specific stages of the cell cycle.
What are the steps in cell-to-cell messaging
Reception, Transduction, Response
What can mutations cause
Mutations can disturb the production of proteins, which could cause death
What is positive feedback? Give examples.
A type of feedback that increases the effects of stimulus. For example child labor, blood clotting, fruit ripening
What occurs in cytokinesis
When the cytoplasm is divided
Explain what contact inhibition in external cell regulation is.
Cell surface receptors that recognize contact with another cell, initiate signal transduction pathways that stop the cell in the G1 phase.
What is paracrine signaling?
Secretory cells release local regulators via exocytosis to an adjacent cell
What are intracellular receptors?
Found in the cytoplasm of the nucleus of target cells and bound to ligands that can pass through the plasma membrane.
What is negative feedback? Give examples
The most common feedback mechanism and this type of feedback reduces the effect of the stimulus. For example sweat, blood sugar, breathing rate
How many cells are created after mitosis occurs
2 identical daughter cells
Explain how cancer invades the cell cycle.
Normal cells become cancerous through DNA mutations. DNA mutations change the DNA. Cancer cells on average have accumulated 60 or more mutations in genes that regulate cell growth.
Why is the phospholipid bilayer so important?
It creates a barrier between the inside and outside of the cell
What are plasma membrane receptors?
They are the most common type of receptor involved in the signal pathway. They bind to ligands that are: polar, water-soluble, large
What are some of the reasons that cause homeostatic imbalances?
Genetic disorders, drug or alcohol abuse, intolerable conditions, diseases such as cancer (the body can’t regulate cell growth) or diabetes (the body can’t regulate blood glucose levels)
What type of reproduction is mitosis
Asexual- creates genetically identical cells
What is the difference between normal and cancerous?
Normal cells- follow checkpoints, divide on average 20-50 times in culture, go through apoptosis when there are significant errors
Cancer cells- don’t follow checkpoints, divide infinitely when in culture- are considered to be “immortal”, evade apoptosis and continue dividing even as errors.