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Lesson overview

LAUNCH · GCSE Biology · Lesson 1 of 18 Enrichment · Introduce

Enzyme Action: Preparing the pH Investigation

Sequence outcome: Edexcel GCSE Biology 1BI0 Foundation · Paper 1 · Topic 1 · enzyme action, pH and Core Practical 1.10 preparation.

🎯 Learning objective: I can explain enzyme specificity and denaturation, then identify the variables and evidence needed to investigate the effect of pH on amylase safely.
✅ Success criteria
  • Use enzyme, substrate, active site and specificity accurately in an explanation.
  • Explain how an unsuitable pH can change an active site's shape and reduce enzyme activity.
  • Identify pH as the independent variable, time to starch disappearance as the dependent variable, and suitable control variables.
Arrival · previous learningStarter · observe / predictI Do · model the reasoningWe Do · hinge & responseI Do 2 · connect / extendWe Do 2 · scientific model / dataIndependent · evidence & transferExit · receive and use the response
🧪 Enzyme Evidence Briefing: make a testable plan before any reagent is opened⏱ 40 minutes🔁 Live Lundy loop↺ Retry without penalty
🧩ACTIVE SITEspecific fit🧪CHANGE PHone variable⏱TIME ENDPOINTobservable evidence
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION

LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.

🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE

SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting

⏱ 4 min
🚪 Arrival · previous learning
Retrieve only what has already been taught
  1. W7 review: enzymes are biological catalysts, but enzyme action was not securely taught in the installed W6–W7 sequence; today's retrieval box supplies the prerequisite facts.
  2. Topic 1: a cell reaction can be investigated by changing one independent variable and measuring one dependent variable.
  3. Osmosis practical: control variables make comparisons more valid.
  4. Lead-in: amylase breaks the substrate starch into smaller sugars.
New to this class, absent, or not sure? Everything needed is in the retrieval box above. Read it, point to it or ask a familiar adult to read it exactly.
◆ Supported
  1. Read or point: an enzyme is a biological catalyst that speeds a reaction without being used up.
  2. Match amylase to its substrate: starch, protein or lipid.
  3. Choose the fair-test rule: change one variable or change every variable together.
  4. Lead-in: point to the active-site shape that could fit the substrate model.
▲ Standard
  1. State what a biological catalyst does.
  2. Name the substrate broken down by amylase.
  3. Explain why temperature and solution volumes should stay constant in a pH investigation.
  4. Lead-in: predict what an extreme pH might do to an enzyme's active site.
★ Stretch
  1. Distinguish catalyst from reactant in one sentence.
  2. Use specificity to explain why amylase acts on starch rather than protein.
  3. Distinguish a control variable from a control sample.
  4. Lead-in: predict how active-site shape could connect pH to reaction rate.
LAUNCH response routes
📝 write / edit🗣 structured verbal📏 measure / calculate📊 graph / interpret🧪 practical / demonstrate↺ re-attempt

Access changes the response route, not the GCSE Biology entitlement.

🔊 Read-aloud route: a familiar adult may read the task exactly while the text remains visible. No device voice or media permission is required.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION

LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.

🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE

SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting

⏱ 4 min
🌱 Starter · observe / predict

Three amylase mixtures contain the same starch and are kept at the same temperature. Which first prediction is scientifically testable?

LOCAL VISUAL HOOK · FRAME 1
Iodine is blue-black when starch is still present.
blue-blackstarch PRESENTblue-blackblue-blackt = 0 s · iodine + starch
Iodine is the starch detector. Blue-black = starch present.
LOCAL VISUAL HOOK · FRAME 2
Iodine stays orange-brown when starch is not detected.
orange-brownstarch NOT detectedblue-blackstarch presentblue-blackstarch presentiodine stays orange-brown when starch has gone
Amylase broke the starch down. No starch → iodine keeps its own colour.
LOCAL VISUAL HOOK · FRAME 3
Equal mixtures at different pH reach the endpoint at different times.
pH 7endpoint 90 spH 5endpoint 180 spH 3no endpoint by 300 ssame starch, same temperature, different pH — different times
Only pH changed. So pH changed how fast amylase worked. That is the investigation.

Commit one first idea. Predictions are held, not marked. Pointing, selecting, saying or signing all count.

QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION

LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.

🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE

SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting

⏱ 5 min
👩‍🏫 I Do · model the reasoning

Make the first scientific idea visible

SPECIFICITYone substrate fitsthe ability of an enzyme's active site to bind a particular substrate
DENATUREactive site changes shapeto change an enzyme's three-dimensional shape so its active site no longer works effectively
VARIABLEwhat changes or is measureda factor deliberately changed, measured or kept constant in an investigation

WHAT THIS MODEL HELPS US SEE

Use the model to connect active-site shape, substrate binding and a measurable endpoint. Record the sentence: pH may affect active-site shape, so we measure the time until starch is no longer detected.

WHAT THIS MODEL DOES NOT SHOW

Card shapes do not show molecular movement, collisions, bonds or gradual changes in protein structure. A neat lock-and-key picture is a simplified representation, not a literal rigid lock.

Step 1

Represent amylase with one active-site shape and starch with a complementary substrate piece. Bind them briefly to show an enzyme-substrate complex.

Step 2

Separate the product pieces and return the enzyme model unchanged. The enzyme can catalyse another reaction and is not consumed.

Step 3

Alter the active-site model to represent denaturation. The substrate no longer fits well, so successful collisions and reaction rate fall.

Word help keeps the scientific term visible and adds a plain-language bridge.

🔑 Active site model · change the pH

One enzyme, one substrate. Press a pH and watch the active site. Specific = only starch fits. Denatured = the shape has changed and nothing fits.

ENZYME (amylase)active sitestarchpH 7 · site fits starch exactly · fastest
pH 7: the substrate fits the active site. Reaction fastest. This is the optimum for amylase (about pH 7).

🧪 Sort the variables

Press a variable, then its type.
Foundation tier: enzyme, substrate, active site, specific, denatured, optimum. Do not add lock-and-key vs induced-fit or activation energy.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION

LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.

🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE

SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting

⏱ 5 min
🤝 We Do · hinge & response

Which statement best explains enzyme specificity?

Everyone commits before explanation.

Use a button, point, say/sign or let an adult operate the chosen button. A retry is information, not a penalty.

QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION

LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.

🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE

SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting

⏱ 4 min
👩‍🏫 I Do 2 · connect / extend

Connect the model to the second idea

Connection: the model is useful when its visible pattern is translated into a scientific explanation.
Connection 1

Translate the model into a testable question: how does buffer pH affect the time amylase takes to digest starch?

Connection 2

Set the variables: IV = buffer pH; DV = time until a sample no longer turns iodine blue-black; CVs include temperature, enzyme and starch concentrations and volumes, sampling interval and mixing method.

Connection 3

Add a negative control sample with starch but no active amylase. It should continue to test positive for starch and helps show that starch loss depends on the enzyme.

MODEL STRENGTH

Use the model to connect active-site shape, substrate binding and a measurable endpoint. Record the sentence: pH may affect active-site shape, so we measure the time until starch is no longer detected.

MODEL LIMIT

Card shapes do not show molecular movement, collisions, bonds or gradual changes in protein structure. A neat lock-and-key picture is a simplified representation, not a literal rigid lock.

QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION

LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.

🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE

SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting

⏱ 4 min
🤝 We Do 2 · scientific model / data

Variables and validity planning console

Route each planning card to independent variable, dependent evidence or control/validity before writing the method.

Read one planning card.Commit it to IV, DV or control/validity.Repair any mismatch using the question being tested.Freeze the plan only when the cause, outcome and fair-comparison conditions are visible.

Cards to place

Matching groups

The investigation question is visible, but the variables are not yet assigned.

🧩 Science glitch · find and repair it

Claim: Planning glitch: change pH, temperature and amylase volume together so the result is more dramatic.

QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION

LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.

🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE

SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting

⏱ 10 min
✏️ Independent · evidence & transfer

Produce a safe, ordered CP 1.10 planning record that another trained person could follow using the centre-approved Pearson method and local risk assessment.

👐 Physical route

Planning sheet, apparatus cards, pH-buffer labels, results-table template and current centre method/risk assessment supplied by the teacher. No reagent handling is required in this Introduce lesson.

Same outcome: I can explain enzyme specificity and denaturation, then identify the variables and evidence needed to investigate the effect of pH on amylase safely.

🖥 Offline digital / director route

Use the in-page planning console, then type an ordered variables table and method outline locally. It prepares the practical but does not certify completion.

Same evidence: A pupil-owned prediction, IV/DV/CV table, ordered method outline, results-table headings and one justified safety/control decision.

🧰 Equipment / setupPlanning sheet, apparatus cards, pH-buffer labels, results-table template and current centre method/risk assessment supplied by the teacher. No reagent handling is required in this Introduce lesson.
🛡 Safety / sensoryThis lesson plans but does not authorise practical work. The teacher/technician must supply the current centre-approved Pearson method, COSHH information and local risk assessment; pupils must not infer concentrations, heating arrangements or disposal from this deck.
🖥 Offline parityUse the in-page planning console, then type an ordered variables table and method outline locally. It prepares the practical but does not certify completion.
No-equipment/access route: Sequence printed method cards and direct an adult to scribe exact decisions. Keep all GCSE variables and safety reasoning.

◆ Supported

Complete a labelled IV/DV/CV table and order six picture-method cards; finish one because sentence about keeping temperature constant.

Scaffold

Use the word bank and sentence stem: We change __. We measure __. We keep __ the same because __.

▲ Standard

Write an ordered method outline, identify variables and control sample, and design a table for pH, endpoint time and rate.

Scaffold

Use numbered steps and the command-word frame: EXPLAIN = point + scientific reason.

★ Stretch

Justify the controls and sampling interval, predict the rate pattern, and identify one source of uncertainty before practical work begins.

Scaffold

Distinguish validity, precision and safety; do not invent an unsupported concentration or heating method.

Evidence gate

1 · Pupil decisionPrediction, question, method or choice is visible.
2 · Observable evidenceA result, source note, model state or adult observation is preserved.
3 · Pupil meaningA pupil-owned prediction, IV/DV/CV table, ordered method outline, results-table headings and one justified safety/control decision.
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION

LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.

🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE

SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting

⏱ 4 min
🎫 Exit · receive and use the response

Finish with an edit or re-attempt on the existing work

Supported

Complete: amylase acts on __. We change __ and measure __.

Standard

Explain why temperature and volumes must be controlled when investigating pH and amylase.

Stretch

Justify the no-amylase control and distinguish it from a control variable.

Adult Audience

The familiar adult genuinely receives the pupil response, then says back the Science they heard or saw. The adult does not add a score or rewrite the pupil.

SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting

Session state is temporary. Reload clears responses; there is no account, upload or saved pupil identity.

⌂ Start
QUESTIONEVIDENCEPATTERNEXPLANATIONAPPLICATIONEVALUATION

LAUNCH rule: explanation is earned through prediction, observation, measurement, calculation or reasoning from evidence.

🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE

SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting

Staff route

TA Brief · Lesson overview

Priority

Settle, wait and protect the learning goal.

Least-prompt move

Use the least prompt needed, then fade it.

Prompt ladder

WAITSELF-PROMPTVISUAL CUEGENERAL VERBALSPECIFIC VERBALMODELDIRECT SUPPORT
Read-aloud availability: a familiar adult can read the exact current task while the text remains visible. Device speech is intentionally omitted so the deck asks for no media permission and stays dependable offline.

Guidance and access

Live Lundy loop

🛡 SPACE
🗣 VOICE
👂 AUDIENCE
⚙ INFLUENCE

SPACE available · VOICE waiting · AUDIENCE waiting · INFLUENCE waiting

Audience is real only when a familiar adult receives the response. Influence is real only when one next teaching move visibly changes.