Cell signaling and Communication
7.1 What are Signals, and how do cells respond to them?
- Signal transduction is a process of a cell reacting to the influx of a signal from extracellular sources by its receptors
- a Signal transduction pathway is the process of signal transduction
- Chemical signals that reach cells by diffusion/circulation includes:
a) Autocrine – diffuse cells that make them
b) Paracrine – diffuse & affect nearby cells
c) Hormones(circulating signals) – signals to distant cells, travel through circulatory organs
- cells do not react unless there IS a receptor that is SPECIFIC to the signal
- Signal Transduction pathway involves 3 actors:
a) are necessary in order for a cell to maintain homeostasis
b) binds to a receptor and activated and causes changes within the cell
a) form a complex within the membrane
b) react to signals such as:
ii) concentration difference
c) change their conformation/dimentional structure when stimulated
a) are sequences of amino acids folded into a particular shape
b) acts as an enzyme, opening the active site of the receptor, forming a Protein Kinase that:
i) is an enzyme that catalyzes the transfer of a phosphate group from ATP to another molecule
ii) leads the receptor proteins to go through phosphorylation, leading to function & shape change
EnvZ + ATP EnvZ-P + ADP (by Protein Kinase)
a) are proteins that the phosphorylated protein binds to
b) are important in three functions:
i) ‘extracellular’ signals lead to ‘internal’ change of the cell through transduction
ii) the altered responder has function (e.g. OmpR has relation to gene expression – on OmpC)
the OmpC(Protein) discretes out, clogging the pore and re-balancing the concentration rate
iii) The signal is amplified in the process – from a single enzyme to many... [continues]
Cite This Essay
(2013, 03). Biology. StudyMode.com. Retrieved 03, 2013, from http://www.studymode.com/essays/Biology-1550562.html
"Biology" StudyMode.com. 03 2013. 2013. 03 2013 <http://www.studymode.com/essays/Biology-1550562.html>.
- MLA 7
"Biology." StudyMode.com. StudyMode.com, 03 2013. Web. 03 2013. <http://www.studymode.com/essays/Biology-1550562.html>.
"Biology." StudyMode.com. 03, 2013. Accessed 03, 2013. http://www.studymode.com/essays/Biology-1550562.html.