Unit 4 Flashcards
What are two ways cells communicate with each other?
Through direct contact and chemical signaling
What is plasmodesmata?
Microscopic channels that traverse the [lant cell walls, enabling transport and communication between them.
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How do immune cells interact?
Through cell-to-cell contact
what are some defects of cell signaling?
Cancer, autoimmunity, and diabetes.
what are some examples of cell-to-cell contact?
A flu shot or plasmodesmata
What are some examples of short distance communication?
paracine signaling, synaptic signaling, quorum sensing, or morphogens
What are some examples of long-distance communication?
Endocrine signaling, insulin, growth hormone, thyroid hormone, testosterone
What are the stages of sending and receiving cell messages?
Reception: when ligand binds itself to its receptor
Transduction: signal is internalized
Response: Initiate cascade of reactions
Where is the signal transduction pathway and what does it include?
It’s in the cytoplasm and it includes protein modification and phosphorylation cascades.
How does signaling begin?
Begins with the recognition of a chemical messenger (ligand) by a receptor protein in a target cell
What do signaling cascades do?
relay signals from receptors to cell targets, often amplifying the incoming signals, resulting in the appropriate actions taking place such as cell growth, secretion of molecules, and gene expression
What do the signal transduction pathways do?
influence how cells respond to the environment
What is quorum sensing?
The use of chemical messengers by microbes to communicate with other nearby cells and to regulate specific pathways in response to population density.
What changes can signal transduction cause?
may result in changes in gene expression and cell function, which may alter phenotypes or result in programed cell death (apoptosis)
What so cytokines do?
Regulate gene expression to allow for cell replication and division
What does the SRY gene do?
Expression may trigger mating gene expression
What does Ethylene do?
Cause changes in the production, of different enzymes allowing fruits to ripen
What does change in the signal transduction pathway cause?
Causes alteration in cellular response
What do mutations affect?
mutations in any domain of the receptor protein or in an component of the signaling pathway may affect the downstream components by altering the subsequent transduction of the signal
What are feedback mechanisms used for?
To maintain their internal environments and respond to internal and external environmental changes.
What is negative feedback?
a mechanism that returns a system back to its target set point if perturbed. It maintains homeostasis for a particular condition regulating physiological processes.
What are examples of negative feedback?
Body temp, heart rate, breathing rate, etc.
What is positive feedback?
A mechanism that moves the variable farther away from the initial set point. It amplifies responses and processes in biological organisms
What are examples of positive feedback?
Blood clotting, childbirth, fruit ripening, etc.
