Term
| An enzyme that removes a phosphate from a protein is called: |
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Definition
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Term
Communication BETWEEN cells can occur by all of the following EXCEPT:
A.) autocrine signaling
B.) paracrine signaling
C.) endocrine signaling
D.) synaptic signaling |
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Definition
A). Autocrine
Cells sends signal to itself |
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Term
Which of the following molecules could most likely serve as an intracellular ligand?
A.) triglycerides
B.) polysaccharides
C.) polypeptides
D.) steroids |
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Definition
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Term
| Channel-Linked receptors work by: |
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Definition
| Opening/closing after binding another molecule |
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Term
| Mast cells release histamines when allergens are encountered. Histamines then bind to receptors on different cells. What term would best describe a histamine? |
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Definition
| LIGAND: A signaling molecule that binds to a specific receptor protein. Initiating signal transduction in cells. |
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Term
| Briefly explain why hydrophobic and hydrophilic ligands are different. Include why hydrophobic ligands are able to bind receptors inside the cell. |
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Definition
| Hydrophobic Ligands bind intracellular, because they can easily cross the membrane. Hydrophilic can not easily cross the plasma membrane and so must bind to receptors in the membrane. |
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Term
| Secretions from one cell affects nearby cells: |
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Definition
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Term
| Involve molecules that can affect cells at far distances: |
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Definition
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Term
| Cells send signals to itself: |
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Definition
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Term
| Neurotransmitters cross a gap between cells: |
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Definition
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Term
| Molecules on the cell surface interact or utilize gap junctions: |
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Definition
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Term
| You have identified a novel cytoplasmic protein. Through sequence analysis you are able to identify the presence of a number of SERINE/THREONINE phosphorylation motifs. Based on these data, you hypothesize that this protein may be a substrate for what kind of enzyme? |
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Definition
| A PROTEIN KINASE: these proteins phosphorylate proteins to alter protein function and the most common kinases act on the amino acids SERINE, THREONINE, and TYROSINE |
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Term
| Briefly explain how phosphorylation and dephosphorylation impact protein function. |
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Definition
The addition or removal of phosphate groups. Phosphorylation of ADP or ATP. The ATP synthesized from
such processes can donate phosphate groups to proteins. The phosphorylation of proteins alters their functions which allows them to transmit information from an extracellular signal through a signal transduction pathway. |
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Term
| Effective signaling requires a SIGNALING MOLECULE, called a LIGAND, and a molecule to which the signal BINDS, called a RECEPTOR PROTEIN. |
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Definition
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Term
| What is a SIGNAL TRANSDUCTION? What initiates signal transduction? |
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Definition
The initiation of the components *** initiates their process, which converts the information in the signal into a cellular response.
Signal transduction occurs when an extracellular signaling molecule activates a cell surface receptor. In turn, this receptor alters intracellular molecules creating a response.There are two stages in this process:
A signaling molecule activates a specific receptor protein on the cell membrane.
A second messenger transmits the signal into the cell, eliciting a physiological response.
In either step, the signal can be amplified. Thus, one signaling molecule can cause many responses. A signal transduction functions much like a switch. |
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Term
| What type of molecules does the book say can be used as signals? |
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Definition
| Peptides, large proteins, individual amino acids, nucleotides and steroids and other lipids. Even dissolved gases are used as signals (ex. NO *Nitric Oxide) |
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Term
| How many signals is a cell of a multicellular organism generally exposed to at one time? How many signals does it respond to? |
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Definition
| Each cell is exposed to hundreds of signals. Each cell only responds to a certain type of signal and ignores the rest. |
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Term
| How does a cell "choose" what signal to bind to? |
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Definition
| The number and kind of receptor molecules determined this |
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Term
| In order for a signal to be received the two molecules involved must have COMPLIMENTARY SHAPES that allow them to BIND to each other |
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Definition
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Term
| After interaction what happens to the shape of the receptor? What role does this play in signaling? |
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Definition
| The binding includes a change in the receptor protein's shape, ultimately producing a response in the cell via a signal transduction pathway. |
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