Investigate biological washing powders
Biological washing powders contain enzymes that break down biological stains; the investigation should compare cleaning under controlled conditions.
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
- Know that genes are sections of DNA and that organisms use enzymes in cellular processes.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which enzyme can break down a protein stain?
What you will learn
- Describe the use of enzyme-containing biological washing powders
- Plan a fair test that investigates cleaning effectiveness
Let enzymes break down stains
Biological washing powders contain enzymes that act on biological stains. Proteases break down proteins, lipases break down fats and amylases break down starch. Smaller soluble products can then be removed from fabric during washing.
Different stains contain different materials, so the relevant enzyme matters. Enzymes work best within suitable temperature and pH ranges; an excessively high temperature can denature them and reduce their activity.
Design a controlled comparison
To compare a biological powder with a non-biological powder, use equal fabric pieces with the same stain, stain amount, drying time, detergent concentration, water volume, temperature and wash duration. A no-detergent control can show how much cleaning happens without detergent.
Measure stain removal consistently, for example by image brightness under fixed lighting or a defined colour scale. Repeat trials to identify variation. Keep the conclusion within the tested stain and wash conditions.
Pause and explain
Why compare detergent powders using the same wash temperature?
Worked example
A protein stain is washed with biological powder at a suitable temperature. Which enzyme acts on the stain, and what is its role?
Show the worked solution
- Identify the stain material.
- Match the enzyme to its substrate.
Answer Protease acts on the protein stain and breaks proteins into smaller soluble products that can be washed away.
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.
Match each stain with a suitable enzyme: protein, fat and starch.
Give me a hint
Recall enzyme substrate specificity.
Compare my reasoning
- Protease acts on protein.
- Lipase acts on fat; amylase acts on starch.
Protease acts on protein, lipase on fat and amylase on starch.
Look for these in your work
- All three matches correct
- Substrates distinguished
Describe a fair test of whether a biological powder removes a protein stain more effectively than a non-biological powder.
Give me a hint
Change powder type while matching the stain and wash conditions.
Compare my reasoning
- Use identical fabric pieces with the same protein stain and stain amount.
- Keep powder concentration, volume, temperature, time and measurement method the same; repeat.
Use identical stained fabric pieces and wash each under the same conditions, changing only the powder type. Measure stain removal consistently and repeat the test to assess variation.
Look for these in your work
- One variable changed
- Controls and measurement included
An enzyme powder cleans a protein stain poorly in very hot water. Explain a possible reason.
Give me a hint
Consider how temperature affects enzyme structure.
Compare my reasoning
- High temperature can alter enzyme shape.
- The substrate may no longer fit the active site effectively.
Very high temperature can denature the protease, changing its active site so it breaks down the protein stain less effectively.
Look for these in your work
- Temperature effect stated
- Enzyme activity linked
Common mistakes
- Saying enzymes are used up as the stain
- Using a temperature that denatures the enzyme
- Comparing fabrics with different stain amounts or wash times
What can you explain now?
Which enzyme can break down a protein stain?
Compare with the explanation
Protease
Proteases act on proteins.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Which enzyme acts on each common biological stain, and what must remain controlled in a washing-powder test?
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.