1. Name________________________Number_______Block__________
You will need blue, yellow, pink, and red colored pencils.
When cells release signal molecules (ligands) to send a message, and the
message is received, a whole host of events take place inside the cell. The
ultimate goal is a response- a gene is turned on, a protein is manufactured, an
enzyme is activated, the cell divides or dies, etc. There are many responses
that could occur, but the pathways to those responses are very similar.
According to Model 1 (above), does the signal transduction pathway occur
inside or outside of a cell?_______________________________
Compare the shape of the ligand in Model 1 to the share of the receptor.
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The four steps (they include the actual release of the signal as a step) are listed
below. Label the diagram above with the Roman numerals to indicate where on
the diagram each step is taking place.
I. Signaling
II. Reception
III. Transduction
IV. Response
On the figure of Model 1, color the molecules that depict amplified proteins.PINK
List several possible responses that could occur due to a signal being received
by a cell.
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Once the response concludes in the cell, what happens to stop the response?
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2. Refer to Model 2 (above), describe the role of a relay protein.
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Using blue and yellow colored pencils-
Color any pairs of molecules that changed from active to inactive YELLOW.
Color any pairs of molecules that changed from inactive to active BLUE.
Which steps include phosphorylation? ________________________________
What step(s) is RECEPTION? ______________________________________
What step(s) is TRANSDUCTION? __________________________________
What step(s) is RESPONSE? ______________________________________
What is the specific response that occurs in Model 2?
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In Model 2, steps 3, 4, and 5 are shown as AMPLIFICATION steps. Describe
what that means in terms of this signal transduction pathway example
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What advantage would there be to an organism if the signal transduction
pathway had several amplification steps?
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Describe what would occur in the cell if the activated protein kinase enzymes
continued to be active for a longer period of time than necessary.
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How would these enzymes be deactivated?
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Using a red colored pencil-
Complete the illustration in Model 2 by adding at least two protein phosphatases
(PP) to show how this signaling pathway would be ended.
In Model 3 (above), what event begins the process of producing a cellular
response? ______________________________________________________
Locate the second messengers in Model 3. Describe the type of diffusion that is
used for the second messengers to enter the cell. _______________________
What activates or opens the transport protein channel that allows the secondary
messengers to enter the cell?
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