FreeMathWorksheet
Worksheet · TN-BIO-O-LVL-42328 · v1.-1

DNA Structure — Practice Worksheet

A single-focus worksheet on dna structure for O Level Biology. Nothing else from genetics is mixed in — every question, from warm-up to reflection, assesses this one objective and builds towards mastery.

CoreCBSE30 min54 marksNo answers on sheet

The full pedagogical ladder, warm-up to reflection.

Grade

O Level

Subject

Biology

Topic

Genetics

Subtopic

DNA Structure

Curriculum

CBSE

Difficulty

Core

Time

30 min

Questions

31

Total marks

54

Worksheet ID

TN-BIO-O-LVL-42328

Version

v1.-1

Format

A4 · US Letter

Preview & download

Print-ready · high-resolution PDF · minimal ink
FreeMathWorksheet

Practice Worksheet

TN-BIO-O-LVL-42328 · v1.-1

DNA Structure

O Level · Biology · Genetics · CBSE

Grade

O Level

Subject

Biology

Topic

Genetics

Subtopic

DNA Structure

Curriculum

CBSE

Difficulty

Core

Time

30 minutes

Total marks

54

Student name

Teacher name

Date

Learning objectives

  • Recognise dna structure accurately in biology contexts.
  • Explain the underlying rule of dna structure in the student's own words.
  • Apply dna structure to multi-step and unfamiliar problems.
  • Justify a chosen method and identify errors in another student's work.

Skills assessed

  • Fluency and recall
  • Method and setting out
  • Reasoning and justification
  • Problem solving in context
  • Self-assessment

Instructions

  1. Write your name, your teacher's name and the date in the header.
  2. Answer every question in the space provided. Continue on the back if needed.
  3. Show all working — method marks are awarded even when the final answer is wrong.
  4. Aim to finish in about 30 minutes.
  5. Complete the reflection box at the end before you hand the sheet in.

Warm-up

Bloom: Remember · 4 marks

Answer quickly. These check you are ready for the topic.

  1. 1.Name one fact you already know about dna structure.

    [1]
  2. 2.Write down one fact you already know about dna structure.

    [1]
  3. 3.Circle one fact you already know about dna structure.

    [1]
  4. 4.Name one fact you already know about dna structure.

    [1]

Recall

Bloom: Remember · 4 marks

Complete from memory. No calculator, no notes.

  1. 1.List the key term used in dna structure described here: item 1.

    [1]
  2. 2.Label the key term used in dna structure described here: item 2.

    [1]
  3. 3.Define the key term used in dna structure described here: item 3.

    [1]
  4. 4.List the key term used in dna structure described here: item 4.

    [1]

FreeMathWorksheet · TN-BIO-O-LVL-42328 · v1.-1

© 2026 FreeMathWorksheet. Licensed for classroom and home use. Redistribution or resale is not permitted.

Page 1 of 4

FreeMathWorksheet · O Level Biology

DNA Structure

Basic Practice

Bloom: Understand · 5 marks

Work through each item. Show the step you used.

  1. 1.Identify part 1 using the rule for dna structure.

    [1]
  2. 2.Match part 2 using the rule for dna structure.

    [1]
  3. 3.Identify part 3 using the rule for dna structure.

    [1]
  4. 4.Identify part 4 using the rule for dna structure.

    [1]
  5. 5.Match part 5 using the rule for dna structure.

    [1]

Guided Practice

Bloom: Understand · 8 marks

The first step is given. Finish the reasoning.

  1. 1.Using the first step given, finish part 1. Step 1 has been started for you.

    [2]
  2. 2.Continue the working for part 2. Step 1 has been started for you.

    [2]
  3. 3.Using the first step given, finish part 3. Step 1 has been started for you.

    [2]
  4. 4.Complete the method for part 4. Step 1 has been started for you.

    [2]

FreeMathWorksheet · TN-BIO-O-LVL-42328 · v1.-1

© 2026 FreeMathWorksheet. Licensed for classroom and home use. Redistribution or resale is not permitted.

Page 2 of 4

FreeMathWorksheet · O Level Biology

DNA Structure

Independent Practice

Bloom: Apply · 10 marks

No scaffolding. Set out your full method.

  1. 1.Determine part 1 on dna structure without help.

    [2]
  2. 2.Solve part 2 on dna structure without help.

    [2]
  3. 3.Determine part 3 on dna structure without help.

    [2]
  4. 4.Calculate part 4 on dna structure without help.

    [2]
  5. 5.Solve part 5 on dna structure without help.

    [2]

Challenge Questions

Bloom: Analyse · 9 marks

Harder items. Attempt every one, even partially.

  1. 1.Deduce the statement in part 1 about dna structure.

    [3]
  2. 2.Show that the statement in part 2 about dna structure.

    [3]
  3. 3.Find and justify the statement in part 3 about dna structure.

    [3]

FreeMathWorksheet · TN-BIO-O-LVL-42328 · v1.-1

© 2026 FreeMathWorksheet. Licensed for classroom and home use. Redistribution or resale is not permitted.

Page 3 of 4

FreeMathWorksheet · O Level Biology

DNA Structure

Real-life Application

Bloom: Apply · 6 marks

Use the skill in context. State units in your answer.

  1. 1.Apply a real biology situation that depends on dna structure.

    [3]
  2. 2.In context, work out a real biology situation that depends on dna structure.

    [3]

Critical Thinking

Bloom: Evaluate · 8 marks

Explain your reasoning in full sentences.

  1. 1.Evaluate whether a student's method for dna structure is or is not efficient.

    [4]
  2. 2.Explain why a student's method for dna structure is or is not efficient.

    [4]

Reflection

Bloom: Create · 0 marks

Not marked. Answer honestly — this guides your next worksheet.

  1. 1.Record how confident you feel with dna structure and what you will practise next.

    [—]
  2. 2.Describe how confident you feel with dna structure and what you will practise next.

    [—]

FreeMathWorksheet · TN-BIO-O-LVL-42328 · v1.-1

© 2026 FreeMathWorksheet. Licensed for classroom and home use. Redistribution or resale is not permitted.

Page 4 of 4

Question progression

Recognition → understanding → application → reasoning → mastery. The ladder adapts to O Level, and every rung stays on dna structure only.

  1. 01Warm-up

    Answer quickly. These check you are ready for the topic.

    Remember4 questions4 marks
  2. 02Recall

    Complete from memory. No calculator, no notes.

    Remember4 questions4 marks
  3. 03Basic Practice

    Work through each item. Show the step you used.

    Understand5 questions5 marks
  4. 04Guided Practice

    The first step is given. Finish the reasoning.

    Understand4 questions8 marks
  5. 05Independent Practice

    No scaffolding. Set out your full method.

    Apply5 questions10 marks
  6. 06Challenge Questions

    Harder items. Attempt every one, even partially.

    Analyse3 questions9 marks
  7. 07Real-life Application

    Use the skill in context. State units in your answer.

    Apply2 questions6 marks
  8. 08Critical Thinking

    Explain your reasoning in full sentences.

    Evaluate2 questions8 marks
  9. 09Reflection

    Not marked. Answer honestly — this guides your next worksheet.

    Create2 questions0 marks

Answer key & solutions

Every worksheet auto-generates a complete key with step-by-step solutions, the marking scheme and teacher notes. It prints as separate pages so the student copy stays clean.

Teacher notes

  • Set the warm-up as a five-minute starter; it diagnoses readiness for dna structure before you teach.
  • Guided practice is the pivot point — circulate here rather than during independent practice.
  • Mark the reasoning questions with the marking scheme bands, not raw totals, so progress is comparable across variants.
  • Students who band Emerging should repeat the Easy variant of this same subtopic before moving on within Genetics.

Common student mistakes

  • Confusing dna structure with a neighbouring idea in genetics.

Teaching tips

  • Model one worked example of dna structure under a visualiser before handing the sheet out.
  • Ask students to predict which question they will find hardest, then check the prediction afterwards.
  • Pair Developing students with Secure students for the guided practice block only.
  • Use the answer key as a self-marking station rather than collecting the sheets in.

Extension activities

  • Challenge worksheet on dna structure with justification-only questions.
  • Design your own dna structure question and write the mark scheme for it.
  • Link dna structure to the next subtopic in Genetics and explain the connection.
  • Ten-minute timed practice to convert accuracy into fluency.

Switch version

Same subtopic · same objectives · different job

Frequently asked

What exactly is in the download?
A 31-question, 54-mark sheet with branded header, objectives, skills, instructions, name and date fields, page numbering, footer branding, copyright, worksheet ID TN-BIO-O-LVL-42328, version v1.-1 and a QR code back to this page.
Does it print correctly on US Letter?
Yes. Switch paper size in the download panel — margins and typography are identical, so nothing reflows or clips.
Is the answer key included?
The student copy prints clean. Toggle answers on to append the answer key, marking scheme and teacher pack.

Related resources

Tutoring

Work through dna structure with a tutor after marking this sheet.

Book a tutor