Cell communication involves both…?
- Responding to incoming signals
- Producing outgoing signals
Signals in cell communication are often _________ ________ but they can also be ___________ __________ (like light or temperature)
Chemical molecules and physical parameters
What are the 2 general reasons cells need to communicate?
- Respond to a changing environment
- Communicate with other cells
What is direct intercellular signaling?
Cell junctions allow signals to directly pass from one cell to another
What is contact-dependent signaling
Molecules bound to the surface of cells serve as signals to other cells encountering them
What is autocrine signaling?
Cells secrete signaling molecules that bind to their own surface receptors
What is paracrine signaling?
Cells release signals that affect nearby cells
What is endocrine signaling?
Signals (hormones) are released into the blood and affect target cells that are far away
What are the three stages of cell signaling?
1) Receptor activation–binding of a signaling molecule causes a confirmational change
2) Signal transduction–activated receptor stimulates proteins to make a signal transduction pathway
3) Cellular response–signal transduction pathway affects the functions and/or amounts of cellular proteins
What are 3 different ways cells respond to signals?
- Alter metabolism
- Alter cell shape or movement
- Alter gene expression
What is a ligand?
It is a signaling molecule that binds noncovalently to its receptor with high specificity
What happens when a ligand binds to its receptor?
It changes the receptor structure, this conformational change transmits the signal across the membrane
The complex that forms between the ligand and its receptor is stable for a _______ period of time.
Limited
The binding and release between a ligand and receptor are relatively rapid and an ________ is reached
Equilibrium
In a Ligand-Receptor complex, what is kd’?
It is a dissociation constant, which is used to quantify the affinity receptors have for their ligands
When ligand concentration is above the Kd value, what happens to the receptors?
They are likely to have ligand bound to them
When ligand concentration is below the Kd value, what happens to the receptors?
Most receptors will not be bound to their ligand
Cell surface receptors are embedded into the plasma membrane to detect what kind of extracellular signals?
Signaling molecules that are small and hydrophilic or too large to pass through the plasma membrane
What are the two important domains in an enzyme-linked receptor?
Extracellular signal-binding domain and an intracellular catalytic domain
Most enzyme-linked receptors function as _________ ________, which means they do what?
Protein kinases; they transfer a phosphate group from ATP to a specific amino acid
____________ alters the structure and function of a protein.
Phosphorylation
What is G-protein receptors named after?
They interact with intracellular proteins called G proteins which can bind to GTP and GDP
What is the function of a ligand-gated ion channel?
A signaling molecule binds to it, which opens and allows the flow of ions across the membrane (allowing facilitated diffusion)
What is ligand-gated ion channels important for?
They are important for communication between neurons and muscle cells
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Chapter 1 - Intro to Biology32
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Chapter 2 - Chemistry I38
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Chapter 3 - Chemistry II47
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Chapter 4 - Cells41
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Chapter 5 - Cell Membranes46
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Chapter 6 - Utilizing Energy68
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Chapter 7 - Photosynthesis43
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Chapter 8 - Cell Communication27
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Chapter 9 - DNA and RNA41
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Chapter 10 - Gene Transcription + Translation48
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Chapter 11 - Non-coding RNA42
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Chapter 12 - Gene Regulation57
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Chapter 13 - Mutation and DNA Repair34
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Chapter 14 - Cell Cycle, Mitosis, and Meiosis63
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Chapter 15 - Genetic Information from Parent to Offspring30
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Chapter 16 - Epigenetics, Linkage, and Extranuclear Inheritance28
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Chapter 17 - Viruses, Bacteria, and Archaea25
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Chapter 19 - Evolution of Life32
