Form 4 BiologyBiologi Tingkatan 4

Chapter 5: Metabolism & EnzymesBab 5: Metabolisme dan Enzim

The chemical reactions of life — how enzymes catalyze metabolic processesTindak balas kimia kehidupan — bagaimana enzim memangkinkan proses metabolik

🎯 What You'll LearnObjektif Pembelajaran

Define metabolism, anabolism, and catabolismMendefinisikan metabolisme, anabolisme, dan katabolisme

Explain enzyme characteristics and mechanism of actionMenerangkan ciri dan mekanisme tindakan enzim

Describe factors affecting enzyme activityMenerangkan faktor yang mempengaruhi aktiviti enzim

Apply knowledge to daily life and industryMengaplikasikan konsep dalam kehidupan dan industri

⚡ MetabolismMetabolisme

Lock-and-Key Mechanism Enzyme (active site) Substrate Enzyme-Substrate Complex Enzyme (unchanged!) P1 P2 SPM KEY: Enzyme is SPECIFIC to its substrate & remains UNCHANGED after reaction Lock = Enzyme | Key = Substrate | Only the correct key fits the lock
TypeJenisDefinitionDefinisiExamplesContoh
AnabolismAnabolismeBuild up (small → large)Pembinaan (kecil → besar)Photosynthesis, Protein synthesisFotosintesis, sintesis protein
CatabolismKatabolismeBreak down (large → small)Pemecahan (besar → kecil)Respiration, DigestionRespirasi, pencernaan
💡 Memory Trick:💡 Trik Ingatan: "Anabolism = Add / Assemble" | "Catabolism = Cut / Collapse""Anabolisme = Assemble (kumpul)" | "Katabolisme = Cut (potong)"
Anabolism vs Catabolism Anabolism Simple → Complex e.g. Glucose → Starch (uses ATP) Catabolism Complex → Simple e.g. Protein → Amino acids (releases ATP)

🔬 Lock & Key ModelModel Kunci dan Mangga

🔑 KEY CONCEPT:🔑 KONSEP UTAMA: Enzymes are specific! The substrate fits exactly into the active site like a key fits a lock. This explains why each enzyme only catalyzes ONE reaction.Enzim adalah spesifik! Substrat muat tepat ke tapak aktif seperti kunci masuk mangga. Ini menerangkan mengapa setiap enzim hanya memangkinkan SATU tindak balas.
FactorFaktorEffect on EnzymeKesan ke atas Enzim
TemperatureSuhu↑ rate until optimum, then denatures↑ kadar sehingga optimum, kemudian ternyahasli
pHpHEach enzyme has optimum pHSetiap enzim mempunyai pH optimum
Substrate conc.Kepekatan substrat↑ rate until all active sites filled↑ kadar sehingga semua tapak aktif terisi
Enzyme conc.Kepekatan enzim↑ rate linearly (more catalysts)↑ kadar secara linear (lebih banyak pemangkin)
Factors Affecting Enzyme Activity Temperature Optimum Denatured Temperature Temperature pH Pepsin (pH 2) Amylase (pH 7) Trypsin (pH 8.5) Substrate Conc. Vmax All active sites occupied SPM: Explain WHY the curve has that shape!
Competitive vs Non-competitive Inhibition Competitive Enzyme Active site blocked Inhib. Similar shape to substrate Blocks active site directly Reversed by excess substrate Non-competitive Enzyme Shape changed! Inhib. Binds at allosteric site Changes enzyme shape NOT reversed by excess substrate

⚡ Quick CheckSemakan Cepat

What happens to an enzyme at temperatures above optimum?Apakah yang berlaku kepada enzim pada suhu melebihi optimum?

ARate increasesKadar meningkat
BEnzyme denaturesEnzim ternyahasli
CActive site expandsTapak aktif mengembang
DSubstrate increasesSubstrat meningkat

🇲🇾 Malaysian Context🇲🇾 Konteks Malaysia

Papain enzyme from papaya is used in meat tenderizers and digestive supplements! Malaysia is a major papaya producer.Enzim papain daripada betik digunakan sebagai pelunakan daging dan suplemen pencernaan! Malaysia adalah pengeluar betik utama.

📋 SPM Practice📋 Latihan SPM

SPM 2022 Paper 2SPM 2022 Kertas 2

Explain how temperature affects the rate of enzyme-catalyzed reaction. [6 marks]Terangkan bagaimana suhu mempengaruhi kadar tindak balas bermangkin enzim. [6 markah]

📌 Exam Tip:📌 Tips Peperiksaan: Discuss: kinetic energy → collisions → optimum → denaturation (bonds break)Bincangkan: tenaga kinetik → perlanggaran → optimum → penyahaslian (ikatan putus)

🃏 FlashcardsKad Imbas

Anabolism?Anabolisme?
Build up reactions (small → large)Tindak balas pembinaan (kecil → besar)
Enzymes are made of?Enzim terdiri daripada?
ProteinsProtein
Active site?Tapak aktif?
Where substrate bindsTempat substrat terikat
Denaturation?Penyahaslian?
Loss of enzyme shape & functionHilang bentuk & fungsi enzim
Optimum pH for pepsin?pH optimum pepsin?
pH 2 (acidic)pH 2 (berasid)