4.1 Cell Communication
What does a ligand do in cell communication?
It binds to a receptor and initiates a cellular response.
What are the 3 steps of signal transduction?
1. Reception
2. Transduction
3. Response
What type of feedback mechanism would sweating be?
Negative feedback
What is produced from mitosis?
What condition can be caused by the accumulation of mutations in genetic material and uncontrolled cell growth?
Cancer
What is used for juxtacrine signaling in animal cells and what is it?
Gap junctions!
Gap junctions are channels between adjacent cells that allow the travel of ions and small molecules.
What is the role of secondary messengers in transduction?
Signal amplification
Name two changes that can affect the ability of the receptor protein.
Mutations and denaturing
What is the order of the stages of mitosis?
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
What is programmed cell death?
Apoptosis
What is synaptic signaling?
An interaction between two nerve cells where electrical signals are sent from one neuron to activate the other.
What is induced fit?
When ligand binding changes the shape of the receptor
Explain what is the difference between negative and positive feedback?
Negative feedback is used to maintain homeostasis and positive feedback is used to amplify a cell process
When do the chromosomes first start to condense?
In prophase
What are the 3 checkpoints in the cell cycle?
G1 checkpoint, G2 checkpoint, and the M checkpoint
Name the 4 types of cell communication and a short explanation.
- Juxtacrine signaling: direct cell-to-cell contact signaling
- Paracrine signaling: short-distance signaling
- Autocrine signaling: self signaling
- Endocrine signaling: long-range signaling (ligands travel through the blood stream)
What are some examples of cellular responses?
- Apoptosis
- Activation of gene expression
- Opening ligand-gated channels
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What are the three steps of interphase?
G1, S, and G2
How long does a cell spend in interphase?
90%
Give an example for each type of cell signaling.
Autocrine: Cancer cells (release their own growth hormones)
Juxtacrine: Plasmodesmata (ligands travel through channels that connect cells)
Paracrine: Neurotransmitters (ligands travel short distances across synapses)
Endocrine: Insulin (a hormone that travels though a blood vessel to reach a receptor)
How do kinases and phosphatases affect molecules?
Kinases transfer phosphates, which activates molecules, and phosphatases remove phosphates, which inactivates molecules.
What would happen if kinases didn't transfer phosphate groups to proteins?
The protiens would stay inactive
What type of reproduction is mitosis?
Asexual reproduction
What checkpoint makes sure that the spindle fibers are attached correctly?
The M checkpoint