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IGCSE · Cambridge (CIE) · 0610

Explain DNA controlling cell reactions through enzyme proteins

DNA controls function through protein production. For an enzyme: coding information → enzyme protein → catalysed reaction. Binding, amount and activity conditions must be supplied before claiming a specific rate.

Chromosomes, genes and proteins pathway · 17.1

Extended only (Supplement); 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

Which protein example connects DNA with control of reaction rate?

What you will learn

  • Connect gene information with an enzyme and its reaction role
  • Use the supplied binding conditions rather than a guaranteed effect

Original teaching model. Counts and records are stipulated; drawings are schematic.

Explain DNA controlling cell reactions through enzyme proteinsDNA controls function through protein production. For an enzyme: coding information → enzyme protein → catalysed reaction. Binding, amount and activity conditions must be supplied before claiming a specific rate.InformationGene coding for an enzymeProductEnzyme protein with a folded shapeFunctionCatalyses a cell reactionEvidence limitPresence is not a measured activityrate
DNA controls function through protein production. For an enzyme: coding information → enzyme protein → catalysed reaction. Binding, amount and activity conditions must be supplied before claiming a specific rate.
Information, material and count key
FeatureMeaning
InformationGene coding for an enzyme
ProductEnzyme protein with a folded shape
FunctionCatalyses a cell reaction
Evidence limitPresence is not a measured activity rate

Connect gene information with an enzyme and its reaction role

DNA controls cell function partly by controlling the production of proteins. Enzymes are one required example: a protein-coding gene provides information used to make an enzyme, and the enzyme catalyses a cell reaction. The DNA does not itself sit in the reaction as the enzyme. Information, protein production and reaction role are connected but different stages.

An enzyme’s amino-acid sequence influences its folded shape, including the active-site region. A suitable active-site shape permits the specified substrate interaction. This links the gene and protein sequence with the earlier enzyme lessons, without claiming every amino-acid change necessarily abolishes all activity or that all enzyme reactions use one identical shape.

Use the supplied binding conditions rather than a guaranteed effect

An original model stipulates enzyme E binds substrate S and helps its conversion to product P under the stated conditions. A second outline is stipulated not to bind S. Under that evidence, the second outline cannot carry out the same model binding step. The drawing alone is not enough to make that prediction unless the binding condition is actually supplied.

A gene can be present while the relevant enzyme is not currently produced at the required amount. Likewise, an enzyme can be present while conditions limit its activity. Do not collapse gene presence, protein amount and measured reaction rate into one observation. The practice traces a defined information-to-function chain rather than diagnosing a person or estimating an unprovided cellular rate.

Pause and explain

A model stipulates a changed outline cannot bind S. What follows within that model?

Put the idea to work

Worked example

In the supplied E–S model, why does the gene not act as the enzyme itself?

Show the worked solution
  1. Locate the gene’s coding-information role.
  2. Identify the protein performing the catalysed-reaction role.

Answer The DNA gene carries information used to produce enzyme E; the enzyme protein, not the gene, acts in the model reaction.

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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

Trace the DNA-to-reaction relationship using an enzyme example.

Give me a hint

Use information, product and function.

Compare my reasoning
  1. Identify gene information producing an enzyme.
  2. Connect the enzyme with a catalysed cell reaction.

DNA gene information is used to produce an enzyme protein, which catalyses a cell reaction and so contributes to control of cell function.

Look for these in your work

  • Include protein production
  • Include reaction role
2 · Independent

Explain the stipulated consequence when one model enzyme outline cannot bind substrate S.

Give me a hint

Use the specified binding condition only.

Compare my reasoning
  1. Identify the absent S-binding step.
  2. Limit the prediction to that model interaction.

The outline cannot carry out the specified binding interaction with S in this model; it does not establish that every enzyme activity in the cell is lost.

Look for these in your work

  • Use the binding evidence
  • Keep the prediction bounded
3 · Transfer

An enzyme gene is present but there is no expression or reaction-rate record. Can its presence establish a measured rate?

Give me a hint

Information availability is not a rate measurement.

Compare my reasoning
  1. Separate gene presence from enzyme production.
  2. Identify missing activity and condition evidence.

No. Gene presence does not establish enzyme amount, activity conditions or a measured reaction rate; those observations are missing.

Look for these in your work

  • Separate evidence categories
  • State missing rate evidence

Common mistakes

  • Gene presence does not automatically establish enzyme amount or rate.
  • A shape effect must respect the supplied binding evidence.
Recall without your notes

What can you explain now?

A model stipulates a changed outline cannot bind S. What follows within that model?

Compare with the explanation

That outline cannot perform the specified S-binding step

The conclusion uses supplied binding evidence.

After trying it yourself, choose your next review. This is your self-assessment.

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Make it stick

Explain connect gene information with an enzyme and its reaction role and use the supplied binding conditions rather than a guaranteed effect. 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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