GCSE Biology Revision - Topic 2 - Organisation - Enzyme Practical and Rate of Reaction

Sep 5, 2026

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Revision notes for GCSE Biology, Topic 2 on Organisation, focusing on enzymes and reaction rate investigations. Includes guidance on outlining an investigation into pH effects on enzyme activity, calculating rate of reaction from measurable changes over time, and interpreting iodine tests and the outcomes for positive versus negative results. Covers independent, dependent, and control variables, and asks how to adapt the test to investigate temperature effects on enzyme activity, linked to practical assessment language and understanding.

LanguageEnglish

CategoryExam

FormatPDF

Pages9

Reading Time23 min

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GCSE Biology Revision - Topic 2 - Organisation

Enzyme Practical and Rate of Reaction

Investigating pH effects on enzyme activity

Rate of reaction (definition and formula)

Iodine test: positive and negative results

Variables: independent, dependent, control

Modifying the investigation for temperature effects

Digestive system and food tests

Plants: xylem, phloem, transpiration, stomata, and potometer

9-1 GCSE Combined Science Biology Topic 2 – Organisation pg 40-75 | | GCSE Biology Revision – Topic 2– Organisation – Enzyme Practical and Rate of Reaction | | | | --- | --- | --- | --- | | Investigating the effect of pH on Enzyme Activity (pg 44) Outline the Method to carry out this investigation
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Suggest how this test could be modified to test the effects of temperature on Enzyme activity?
Rate of Reaction (pg 44)
The rate of reaction can be determined as the ________ of change
that has occurred _______ by the ______ taken.
RATE = ___________
What does Iodine test for?
Positive test Negative test | | What is an Independent Variable?
What is the Independent Variable in this practical? What is an Dependent Variable?
What is the Dependent Variable in this practical? What is a Control Variable?
What is the Control Variables in this practical? How was the Iodine used in the test to show the enzyme was effecting the reaction? | | GCSE Biology Revision – Topic 2– Organisation – digestive system and food tests | The digestive system pg 46
Label the organs, describe what happens. | | | --- | --- | | Add
| protease, lipase amylase | Food tests pg 47-48 | Food type | Describe the test (chemicals added etc) | Positive result | Negative result | | --- | --- | --- | --- | | Sugar | Add Benedict’s solution and heat to 75oC | | | | Starch | | Turns Black | | | Protein | | | Stays blue | | Lipid | | | | Hazards: ? GCSE Biology Revision – Topic 2– Organisation – Health and disease pg 62-66 | GCSE Biology Revision – Topic 2– Organisation – Plants pg 68-72 | | | | | --- | --- | --- | --- | |

The purpose of the xylem is The purpose of phloem is | | | | | Structure function Helps reduce water loss by evaporation Air spaces in spongy mesophyll Tightly packed layer of cells full of chloroplasts These cells open and close the stomata Stomata Carries water from roots to leaves phloem epidermis | •Explain what transpiration is List 4 risk factors that affect the rate of transpiration
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4) | •Draw and label a diagram to explain how a potometer works | | | | |

•Explain how stomata open and close | |

FAQs

What does the iodine test show, and how are positive and negative results recorded?

The worksheet asks what iodine test for and provides a positive test and negative test column to record the outcome during the starch-related practical context.

Sep 5, 2026

Upload by Mabel