Explain DNA controlling response through neurotransmitter receptors
DNA information produces a neurotransmitter receptor protein. The signal and receptor are different molecules; a predicted response needs the specified binding and membrane conditions.
Exam scope and assessment notes
Extended only (Supplement) · Biology 0970, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked; human subject-teacher review, supervised practical competence and cumulative assessment remain pending. Cambridge states that IGCSE 0970 has the same subject content as IGCSE 0610, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
Before you begin
- Recall the nucleus, DNA base pairing, gametes, fertilisation, enzymes, membrane carriers and chemical synapses.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which is the protein product in this DNA-control example?
What you will learn
- Connect gene information with a receptor protein
- Distinguish a signal molecule from the responding receptor
Original teaching model. Counts and records are stipulated; drawings are schematic.
| Feature | Meaning |
|---|---|
| Information | Receptor-coding gene |
| Product | Receiving-membrane receptor |
| Signal | Released neurotransmitter |
| Function | Specified signal binding and response |
Connect gene information with a receptor protein
Receptors for neurotransmitters are the third required protein example in this section. Gene information is used to produce a receptor protein at the responding membrane. A suitable neurotransmitter can bind that receptor and contribute to a response under the stated synapse model. The receptor is not the neurotransmitter, the whole neurone or the DNA gene itself.
The neurotransmitter is released by the sending side of the chemical synapse and diffuses across the gap. The receptor protein is on the receiving side and has a suitable binding relationship with the signal. This connects the earlier chemical-synapse pathway with DNA control of cell function through the production of proteins that allow a response.
Distinguish a signal molecule from the responding receptor
An original model stipulates that signal N needs receptor R for the depicted receiving-membrane response. If R is absent, N cannot initiate that particular R-dependent step, even if N reaches the membrane. The prediction does not prove all other signals or receptors fail; it is bounded by the specified interaction and any other pathways retained in the record.
A gene for receptor R being present does not establish how much R is expressed or located at the membrane, nor the complete timing of a neurone response. The original diagram keeps DNA information, receptor protein, signal arrival and response separate. Explain the mechanism without inventing a clinical conclusion or using a schematic colour as receptor-binding evidence.
Pause and explain
What follows if the stipulated R-dependent model lacks R?
Worked example
Why is neurotransmitter N not the same molecule as receptor R?
Show the worked solution
- Identify N as the signal crossing the gap.
- Identify R as the protein receiving the signal at the membrane.
Answer N is the released signal; R is the receiving-membrane receptor protein with the specified binding relationship.
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Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
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Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Trace the gene-to-receptor-to-response relationship.
Give me a hint
Keep information, protein and signal interaction distinct.
Compare my reasoning
- Identify gene information producing receptor R.
- Connect N binding R with the specified response.
DNA gene information is used to produce receptor R; neurotransmitter N can bind R and contribute to the specified receiving-membrane response.
Look for these in your work
- Include receptor production
- Include signal interaction
Distinguish the sending signal from the receiving protein at a chemical synapse.
Give me a hint
Use neurotransmitter and receptor.
Compare my reasoning
- Identify the released neurotransmitter crossing the gap.
- Identify the receiving-membrane receptor protein.
The neurotransmitter is the released signal; the receptor is a protein at the receiving membrane that binds the suitable signal.
Look for these in your work
- Name the signal
- Name the receptor and location
Signal N arrives but required receptor R is absent; a different receptor route is also supplied. Does every response stop?
Give me a hint
Keep the specified N/R route separate from other routes.
Compare my reasoning
- Identify the missing R-dependent response step.
- Retain the stated alternative route.
The specified N/R step is unavailable, but the record does not prove the separate receptor route or every response has stopped.
Look for these in your work
- Use the receptor requirement
- Retain alternative evidence
Common mistakes
- Signal and receptor are different molecules.
- A missing specified receptor does not prove every response pathway is absent.
What can you explain now?
What follows if the stipulated R-dependent model lacks R?
Compare with the explanation
The specified N-to-R response step is unavailable
The prediction respects the defined receptor requirement.
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Make it stick
Explain connect gene information with a receptor protein and distinguish a signal molecule from the responding receptor. Use the stated cell, chromosome sets and information pathway before opening the solutions.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.