Cell signalling: a receptor selects the response
導入済み| English | 意味 |
|---|---|
| receptor/rɪˈseptə/ | 受容体 |
| signal transduction/ˈsɪɡnl trænsˈdʌkʃn/ | シグナル伝達 |
What would explain this observation?
- Two cell types encounter the same signal but respond differently. Their receptors 受体 and internal pathways determine what follows.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- A signalling molecule binds a compatible receptor. Receptor activation can initiate signal transduction 信号转导 through intracellular molecules. The resulting response may change enzyme activity, transport or gene expression. A signal need not enter the cell to cause an effect.
- receptor: A molecule that binds a compatible signal; signal transduction: Conversion of signal reception into intracellular changes.
Why can one signal produce different effects in two cell types?
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A signal's effect is decided by the receiving cell: different receptors or different internal pathways turn the same signal into different responses. The signal molecule itself carries no instruction beyond binding.
Match each technical term to its precise meaning.
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Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Distinguish signal reception, transduction and response. Amplification can allow a small extracellular change to produce a larger intracellular effect. Different receptors or pathways can give different responses to one signal.
- Use an attributed dataset comparing signal concentration and response. Include an untreated control and, where supplied, receptor-blocking evidence. Do not infer the whole pathway from a concentration-response graph alone.
Which two habits make the investigation or model in this case more defensible?
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Stating the conditions and assumptions lets others repeat the work exactly, and recording the supporting evidence lets them check the conclusion. Hiding disagreeing results removes the evidence that could challenge a wrong conclusion, and one measurement can never establish a wider claim.
Work from known quantities
- State the known values and their units. Choose the relation because its assumptions fit this case, then rearrange before substitution.
- Known: response increases from 20 to 80 units. Fold change = 80/20 = 4. Percentage increase = (80−20)/20 × 100 = 300%. A fourfold final value is not a 400% increase.
Response rises from 10 to 50 units. Calculate the fold change. Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
Response rises from 10 to 50 units. Calculate the fold change.
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The result is 5 . Known: response rises from 10 to 50 units. Use fold change = final / initial. Fold change = 50/10 = 5. Note this is a fivefold final value, which corresponds to a 400% increase, not a 500% one.
Check the conclusion and its limits
- A receptor is not interchangeable with every signalling molecule. Greater signal concentration does not imply unlimited response once the system saturates.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
Fourfold final response means a 400% increase from baseline. This claim is false: A fold change is a ratio of final to initial; a percentage increase is the change relative to the initial value. A fourfold final value means a 300% increase, so "fourfold" and "400%" are not interchangeable.
Cell signalling: a receptor selects the response: Distinguish signal reception, transduction and response. Amplification can allow a small extracellular change to produce a larger intracellular effect. Different receptors or pathways can give different responses to one signal.
Fourfold final response means a 400% increase from baseline.
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A fold change is a ratio of final to initial; a percentage increase is the change relative to the initial value. A fourfold final value means a 300% increase, so "fourfold" and "400%" are not interchangeable.
A molecule that binds a compatible signal: write the technical term.
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receptor means A molecule that binds a compatible signal.