Year 6 Science exam worksheet exploring yeast fermentation and mould growth variables to evaluate student understanding.
An end-of-topic assessment combining multiple choice recall questions with longer written answers, designed to test understanding across the full ability range.
Subject: Science | Year: 6
Name: _________________________ Class/Set: ____________ Date: ____________
Mark the correct answer.
Q1: Which of the following is a type of microorganism used in the production of bread to make it rise?
a) ☐ Bacteria b) ☐ Virus c) ☐ Yeast d) ☐ Algae
⇨ The data provided in the table below shows the growth of mould on three different slices of bread kept in different conditions over five days.
| Bread Sample | Condition | Growth Observed (cm²) |
|---|---|---|
| Sample A | Warm and Damp | 12.5 |
| Sample B | Cold and Damp | 2.1 |
| Sample C | Warm and Dry | 0.4 |
Q2: Based on the results in the table, which combination of conditions most significantly promotes the growth of the microorganism 'mould'?
a) ☐ Cold and dry conditions b) ☐ Warm and damp conditions c) ☐ Cold and damp conditions d) ☐ Warm and dry conditions
Q3: Microorganisms can be both helpful and harmful. Which of these is an example of a harmful microorganism?
a) ☐ Lactobacillus used to make yoghurt b) ☐ Penicillium used to create antibiotics c) ☐ Yeast used in brewing d) ☐ Influenza causing the flu
Q4: Why are viruses often considered different from other microorganisms like bacteria or fungi?
a) ☐ They are much larger than bacteria b) ☐ They can only survive and replicate inside a living host cell c) ☐ They are always helpful to humans d) ☐ They can be seen clearly without a microscope
Q5: If a scientist wanted to prevent the growth of bacteria in a laboratory sample, which action would be most effective?
a) ☐ Increasing the temperature to 37°C b) ☐ Adding a supply of sugar and water c) ☐ Placing the sample in a vacuum-sealed, frozen container d) ☐ Providing a dark, humid environment
Answer in the spaces provided.
Q6: Explain why most perishable food items, such as milk or cooked meat, are stored in a refrigerator at 4°C. [3 marks]
⇨ The following scenario describes an investigation into the effect of sugar on the activity of yeast in a warm water solution.
A student placed 5g of yeast into two separate beakers containing 100ml of warm water. In Beaker A, they added 10g of sugar. In Beaker B, no sugar was added. After 20 minutes, Beaker A had a thick layer of foam on top, while Beaker B showed no change.
Q7: Explain the biological process occurring in Beaker A and suggest why the results differed between the two beakers. [4 marks]
Total Marks: _______ / 12
⚠ TEACHER’S GUIDANCE
Q1: c
Explanation: Yeast is a single-celled fungus that ferments sugar, producing carbon dioxide gas which causes bread dough to rise.
Q2: b
Explanation: Microorganisms like mould require warmth, moisture, and a food source to grow rapidly. Sample A shows the highest growth area (12.5cm²) due to the presence of both heat and dampness.
Q3: d
Explanation: Influenza is a virus that causes illness. The other options describe microorganisms used beneficially in food production or medicine.
Q4: b
Explanation: Unlike bacteria or fungi which can often grow on decaying matter or agar, viruses require a living host to reproduce.
Q5: c
Explanation: Bacteria require warmth and moisture to thrive. Freezing and removing air (vacuum-sealing) halts the metabolic processes and prevents growth.
Model Answer: "Food is kept in a fridge because the cold temperature (4°C) slows down the rate at which bacteria and mould can grow and multiply. This means the food stays fresh for longer and is safer to eat because it reduces the chance of harmful bacteria reaching dangerous levels."
Model Answer: "In Beaker A, the yeast is consuming the sugar and performing a process called fermentation (or respiration). This process releases carbon dioxide gas, which creates the foam seen on the surface. Beaker B did not change because microorganisms need a food source, like sugar, to grow and be active. Without the sugar, the yeast remained dormant."
Identifying the distinction between helpful and harmful microbes often presents a significant hurdle for Upper Key Stage 2 learners. This resource addresses this by integrating a comparative data table regarding mould growth on bread samples, which forces pupils to move beyond simple recall into empirical analysis. The architecture within an exam worksheet utilizes a gradient of difficulty to manage cognitive load, transitioning from low-stakes multiple-choice retrieval to high-stakes application in the yeast activity scenario. This strategic scaffolding ensures that Year 6 students develop the reasoning independence required for SATS, effectively bridging the gap between substantive knowledge and the evaluative demands of the science curriculum.
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