Mitosis and Cell Communication Flashcards
Quorum sensing
Concentration of signaling molecules released by bacteria that allows bacteria to sense local population density
Autocrine singling
when a cell signals itself
Paracrine signaling
when a cell signals a cell next to it
Endocrine signaling
when a cell signals other cells down the bloodstream, or just a long distance away
Positive Feedback Loops
-Enhance/amplify changes
-Moves a system away from equilibrium
-ex. childbirth and fruit ripening
Negative Feedback Loops
-Dampen or buffer changes
-goal is to return a system to equilibrium
-ex. blood glucose and thermoregulation
What are the three stages of cell signaling?
Reception, Transduction, Response
What happens during reception?
The ligand binds with the receptor, changing it’s shape, which is the mechanism by which the signal is passed
What happens during transduction?
The activated receptor triggers a chain of biochemical reactions in the cell, many enzymes are involved, and the entire reaction is called a SIGNAL CASCADE
What happens during response?
The signal cascade results in a specific cellular response
What are the three types of membrane receptors?
-G protein-coupled receptors
-Receptor tyrosine kinases
-Ion channel receptors
Protein Kinases
Transfer phosphates from ATP to protein through phosphorylation
What are the three phases of interphase?
G1, S, G2
What happens during G1?
Not much, the cell grows, prepares to duplicate DNA
What happens during S?
The DNA is replicated
What happens during G2?
Rapid growth of the cell and protein synthesis as cell prepares for mitosis
What are the phases of mitosis?
Prophase, Metaphase, Anaphase, Telophase
What happens during Prophase?
-Nucleolus disappears as chromatin condenses forming chromosomes
-Centrosomes move to opposite poles of cell
-spindle fibers start to form
What happens during Metaphase?
-Spindle fibers attach to center of centrosome
-Line up chromosomes in a line along the equator
What happens during Anaphase?
-Spindle fibers shorten and pulls sister chromatids apart
-Chromatids pulled to opposite poles of cell
What happens during telophase?
-Two nuclei form around DNA
-A cleavage furrow forms
What happens during cytokinesis?
The cell is split down the middle along the furrow
