chapter. 11 cell communication

Q. what are the three steps of cell communication?

Signal reception, Signal transduction, and Cellular response

Q. what are the three type most signal recept which are plasma-membrane proteins?

G-Protein-Linked Receptors

Tyrosine-Kinase Receptors.

Ion-Channel Receptors

Q. what is apoptosis?
a type of programmed cell death that intergrates input from multiple signaling pathways.



five facts


1. in order to communicate the cell to cell, they need to go through three steps which is

Signal reception, Signal transduction, and Cellular response

2. some cell signaling is only existed for short distance communicating, while some other signaling is for long communicating.


3. in G protein-coupled recpetor, G protein isnt moveing once the signling molecules gets to activated receptor, the G protein needs GTP in order to move and carry the signal to the enzyme and response to it.


4. there are a lot of steps that one signal is reach into the response but it happens immediately such as my brain controls to move my arms around and the arms moves as soon as I think to move


5. Cells may also communicate by direct contact. Both animals and plants have cell junctions that provide cytoplamic continuity between adjacent cells. Also, animal cells may communicate via direct contact between molecules on their surfaces



key terms


1.protein phosphatases
enzymes that can rapidly remove phosphate groups from proteins
2.signal transduction pathway
the process by which a signal on a cell's surface is converted to a specific cellular response is a series of steps called
3.protein kinase
the general name for an enzyme that transfers phosphate groups from ATP to a protein
4.adenylyl cyclase
an enzyme embedded in the plasma membrane
5.second messengers
many signaling pathways also involve small, nonprotein, water-soluble molecules or ions called
6.scaffolding proteins
large relay proteins to which several other relay proteins are simultaneously attached
7.ligand-gated ion channel
a type of membrane receptor containing a region that can act as a "gate"when the receptor changes shape
8.G protein
a protein that binds the energy-rich molecule GTP
9.apoptosis
cells that are infected or damaged or that have simply reached the end of their functional life span often enter a program of controlled cell suicide
10.ligand
the term for a molecul that specifically binds to another molecule, often a larger one. binding generally causes a receptor protein to undergo a change in shape.

diagram
the first picture is about Paracrine signaling which a secreting cell acts on nearby target cells by discharging molecules of a local regulator into the extracellular fluid
second picture is synaptic signaling which a nerve cell releases neurotransmitter molecules intpo a synapse, stimulating the target cell
third one is hormonal signaling which specialized endocrine cells secrete hormones into body fluids, often the blood. Hormones may reawch virtually all body cells.
Local and long-distance cell communication in animal, in both of them, only specific target cells recognize and respond to a given signaling molecules.


video
http://www.youtube.com/watch?v=U6uHotlXvPo

summary

Cell-to-Cell communication is absolutely essential for multicellular organisms. The signals received by cells, whether originating from another cell or from some change in the organism's physical surroundings, take various forms. Cells can sense and respond to electromagnetic signals, such as light, and to mechanical signals, such as touch. However, cells most often communicate with each other using chemical signals. We will deal here with the main mechanisms by which cells detect, process, and respond to chemical signals sent from other cells.