Describe chromosomes as DNA carrying genes
A plant or animal nuclear model contains chromosomes whose DNA carries genes. Nuclear boundary, chromosome DNA and gene region are different levels of the same information relationship.
Section 17.1 · Chromosomes, genes and proteins
Exam scope and assessment notes
Core and Extended · 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 is genetic information carried in a chromosome?
What you will learn
- Locate genetic information in chromosome DNA
- Separate a chromosome from the cell nucleus
Original teaching model. Counts and records are stipulated; drawings are schematic.
| Feature | Meaning |
|---|---|
| Nucleus | Containing structure in the stated cell |
| Chromosome | DNA packaged with associated proteins |
| Gene | Information region within DNA |
| Drawing limit | Colour and shape do not give a base sequence |
Locate genetic information in chromosome DNA
A chromosome carries genetic information in a long DNA molecule. In the plant and animal cells used in this pathway, chromosomes are found in the nucleus. DNA is packaged with associated proteins; saying chromosomes are made of DNA does not mean a chromosome contains no other material. The DNA contains regions called genes, which carry information used by the cell.
The nucleus is a cell structure containing chromosomes, not another name for one chromosome. A chromosome is also not the whole cell or a protein made from a gene. These distinctions connect the earlier cell and DNA lessons with inheritance: genetic information resides in DNA, while the nucleus is the location of that information in the stated cell model.
Separate a chromosome from the cell nucleus
Diagrams often draw chromosomes as coloured rods or X shapes to make information easy to follow. A rod in this lesson represents a chromosome without requiring a particular cell-division stage. An X-shaped drawing represents a particular replicated, condensed form, not the permanent shape of every chromosome. Colour and size on a schematic are labels rather than evidence of a real species or chromosome count.
The original model marks a gene region on chromosome DNA inside a nuclear boundary. Follow the relationship from nucleus to chromosome to DNA region rather than treating the labels as separate objects with identical meanings. When an image supplies only an outline, do not invent an exact gene sequence or chromosome number from that appearance.
Pause and explain
Which distinction is correct?
Worked example
A diagram labels the nuclear boundary as one chromosome. What must change?
Show the worked solution
- Identify the nucleus as the containing structure.
- Place chromosome DNA within the stated nuclear model.
Answer The boundary labels the nucleus; chromosomes containing DNA lie within it.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
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.
Describe the relationship between chromosome DNA and genes.
Give me a hint
Use information and DNA regions.
Compare my reasoning
- Identify DNA as chromosome material carrying information.
- Identify genes within that DNA.
Chromosomes contain DNA carrying genetic information in the form of genes.
Look for these in your work
- Name DNA
- Locate genes in it
Repair a labelled model that calls the nucleus a protein and the chromosome a cell.
Give me a hint
Use containing structure and DNA-bearing structure.
Compare my reasoning
- Identify the nucleus as a cell structure.
- Identify the chromosome as DNA-bearing material inside it.
The nucleus is the containing cell structure; a chromosome is a DNA-bearing structure within the stated plant or animal nucleus.
Look for these in your work
- Repair both labels
- Retain the stated cell context
A coloured rod drawing supplies no sequence key. Can it establish the exact bases of a gene?
Give me a hint
A shape label is not a sequence record.
Compare my reasoning
- Identify the schematic’s structural role.
- State that base information has not been supplied.
No. The drawing represents a chromosome but does not supply the exact gene base sequence; colour and rod shape do not establish it.
Look for these in your work
- Distinguish structure and sequence
- State missing evidence
Common mistakes
- A nucleus is not one chromosome.
- Chromosome diagrams are not permanent-shape photographs.
What can you explain now?
Which distinction is correct?
Compare with the explanation
The nucleus contains chromosomes; genes are regions of DNA
The locations and information regions are different.
After trying it yourself, choose your next review. This is your self-assessment.
Your review choice appears on Today. Sign in to sync it across devices.
Make it stick
Explain locate genetic information in chromosome DNA and separate a chromosome from the cell nucleus. 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.