Cell Signaling (Unit 4) Flashcards
What structure allows direct contact communication in animals
Gap junctions
What sturcture allows direct contact communication in plants?
Plamsodesmatas
Explain direct contact communication with an example
Direct contact the cytoplasm of adjacent cells (signaling substances pass freely)
ex immune cells
Antigen presenting cells -> helper T cells -> killer T cells
Explain short distance signalling with an exaple
A cell produces a signal to induce changes in near by cells (local action) that are secreted into extracellular enviroment
ex neurotransmitters
Synaptic signalling occurs in the animal nervous system when a neurotransmitter is released in response to an electric signal
What is quorum sensing?
A process in which bacteria sense local population density by concentration of signalling molecules
What does quorem sensing allow bacteria to do?
To develop and coordinate activities and live in community structures
Explain long distance signalling with an example
Endocrine signalling: Speciallized cells release hromones which travel to target cells via the circulatory system
What is autocrine signaling
A cell signalling itself
What is a protein domain?
A distinct functional unit in a protein that is responsible for a particular job
Part of the tertiary structure
What are recceptors?
Transmembrane proteins that undergo a shape change when the lygand bonds, so the domain in the cytoplasm changes.
What are G proteins?
Capable of binding Gtp and GDP
Integral membrane proteins that bind water soluble molecules
What are receptor tyrosine kineases (RTK’s)?
They attach tyrosine to kinases
What are kinases?
An enzyme that catalyzes the transfer of phosphate groups to substrates. (phosphorylation)
Describe amplification
Individual signaling reactions can produce a large amount of cellular products or subsequent intracellular reactions
Why is amplification imprtant?
It ensures a response is generated in face of opposing influences
