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IGCSE · Cambridge (CIE) · 0610

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

Chromosomes, genes and proteins pathway · 17.1

Core and Extended; Biology 0610, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked

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.

Describe chromosomes as DNA carrying genesA 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.Nucleus · selected chromosomeEnlarged DNA viewMarked gene region · not to scaleCoding informationUsed in protein productionDNA does not become amino acids
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.
Information, material and count key
FeatureMeaning
NucleusContaining structure in the stated cell
ChromosomeDNA packaged with associated proteins
GeneInformation region within DNA
Drawing limitColour 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?

Put the idea to work

Worked example

A diagram labels the nuclear boundary as one chromosome. What must change?

Show the worked solution
  1. Identify the nucleus as the containing structure.
  2. Place chromosome DNA within the stated nuclear model.

Answer The boundary labels the nucleus; chromosomes containing DNA lie within it.

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Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.

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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.

1 · Guided

Describe the relationship between chromosome DNA and genes.

Give me a hint

Use information and DNA regions.

Compare my reasoning
  1. Identify DNA as chromosome material carrying information.
  2. 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
2 · Independent

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
  1. Identify the nucleus as a cell structure.
  2. 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
3 · Transfer

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
  1. Identify the schematic’s structural role.
  2. 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.
Recall without your notes

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.

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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.

Keep learning Biology

Course scope and assessment

780 sequenced lessons provide 2340 guided, independent and application problems in characteristics, classification, cells, organisation, specimen size, membrane transport, biological molecules, enzymes, plant and human nutrition, plant transport, circulatory systems, the heart, blood vessels, blood, disease transmission, body defences, immunity, gas exchange in humans, respiration energy uses and investigations, aerobic respiration, anaerobic respiration and recovery, excretion in humans, coordination and response, sense organs, hormones, homeostasis, tropic responses, drugs, asexual reproduction, sexual reproduction, sexual reproduction in plants, sexual reproduction in humans, sex hormones in humans, sexually transmitted infections, chromosomes, genes and proteins, mitosis, meiosis, monohybrid inheritance, variation, adaptive features, selection, energy flow, food chains and webs, nutrient cycles, population, community, ecosystem, population-growth phases, food supply, habitat destruction, pollution, conservation, biotechnology and genetic modification. 61 of 61 syllabus sections have linked teaching and staged practice. The earlier inheritance overview remains introductory, and the monohybrid pathway develops the relevant Core and Supplement requirements. This is not full programme completion or guaranteed exam readiness. Written practice is self-checked.

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