Keep the gene in the nucleus while its information is used
The original gene remains as nuclear DNA. mRNA, not a moved chromosome segment, carries the information toward protein assembly in the cytoplasm.
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
Where does the protein-coding gene remain in the stated cell model?
What you will learn
- Separate the location of DNA from its information copy
- Reject a whole-gene movement or material-conversion model
Original teaching model. Counts and records are stipulated; drawings are schematic.
| Feature | Meaning |
|---|---|
| Source | DNA gene in the nucleus |
| Message | mRNA information copy |
| Movement | Message reaches the cytoplasm |
| Boundary | Gene stays nuclear in this model |
Separate the location of DNA from its information copy
In the plant or animal cell model used here, the DNA gene coding for a protein remains in the nucleus. Protein production uses information from that gene without moving the whole gene out to a ribosome. This is the first boundary in the required Extended sequence: the original nuclear information is distinct from the message that later reaches the cytoplasm.
An mRNA molecule is made using the gene’s information. It serves as a message copy in the limited syllabus model, while the DNA region remains part of its chromosome. The cell does not remove a chromosome segment each time a protein is made, and making a message does not convert the nuclear gene into the finished protein.
Reject a whole-gene movement or material-conversion model
The original two-location diagram keeps the DNA label inside a nuclear boundary and places a message arrow across to the cytoplasm. The arrow represents movement of mRNA information, not export of the DNA chromosome. This distinguishes the source from its copy and helps prevent an incorrect answer saying the gene passes through the ribosome.
The lesson covers the stated nuclear cell model. Not every organism or cell has this organisation; the earlier prokaryote lesson explained a different arrangement. The Cambridge requirement here is the bounded production sequence in the supplied nucleus-and-cytoplasm setting, without detailed mechanisms of transcription or translation.
Pause and explain
What crosses to the cytoplasm in the required sequence?
Worked example
A diagram moves the chromosome into a ribosome. What should move instead?
Show the worked solution
- Keep the DNA gene in the nucleus.
- Use an mRNA information copy moving to the cytoplasm.
Answer The gene remains in the nucleus; mRNA carries its information to the cytoplasm and passes through the ribosome.
Try a topic test
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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.
State where the original gene remains during the required protein-production sequence.
Give me a hint
Distinguish source from copy.
Compare my reasoning
- Identify the DNA gene.
- Keep it in the nucleus.
The DNA gene coding for the protein remains in the nucleus.
Look for these in your work
- Name original DNA
- Give nuclear location
Correct a model that sends the original gene through a ribosome.
Give me a hint
Change the moving label without changing the source location.
Compare my reasoning
- Keep the gene in the nucleus.
- Replace the exported label with mRNA.
The gene stays in the nucleus; an mRNA information copy moves to the cytoplasm and passes through ribosomes.
Look for these in your work
- Repair the source location
- Repair the moving molecule
A record shows three messages made from a gene. Does it establish the gene was removed three times?
Give me a hint
Making copies does not consume the source.
Compare my reasoning
- Identify message copies as distinct molecules.
- Retain the original DNA in the nuclear model.
No. Three mRNA messages can use the same source information; the record does not mean the DNA gene was removed or consumed.
Look for these in your work
- Distinguish source and copies
- Reject gene consumption
Common mistakes
- The original DNA gene does not leave for the ribosome.
- An information copy is not the original chromosome.
What can you explain now?
What crosses to the cytoplasm in the required sequence?
Compare with the explanation
mRNA carrying the information copy
It links nuclear information with ribosome assembly.
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Make it stick
Explain separate the location of DNA from its information copy and reject a whole-gene movement or material-conversion model. 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.