Form 4 BiologyBiologi Tingkatan 4

Chapter 6: Cell DivisionBab 6: Pembahagian Sel

The process of life — mitosis and meiosis explainedProses kehidupan — mitosis dan meiosis dijelaskan

🎯 What You'll LearnApa yang Anda Akan Pelajari

Define cell cycle and its phasesMendefinisikan kitaran sel dan fasanya

Describe the stages of mitosis and meiosisMenerangkan peringkat mitosis dan meiosis

Compare mitosis and meiosisMembandingkan mitosis dan meiosis

Understand uncontrolled cell division and cancerMemahami pembahagian sel yang tidak terkawal dan kanser

🔬 The Cell CycleKitaran Sel

PhaseFasaDescriptionKeterangan
G1 PhaseFasa G1Cell grows, organelles duplicateSel membesar, organel berganda
S PhaseFasa SDNA synthesis — chromosomes replicateSintesis DNA — kromosom bereplikasi
G2 PhaseFasa G2Final preparations for divisionPersediaan akhir untuk pembahagian
M PhaseFasa MMitosis + CytokinesisMitosis + Sitokinesis
💡 Memory Trick:💡 Trik Ingatan: "G1 = Grow, S = Synthesize, G2 = Get ready, M = Multiply!G1 = Membesar, S = Mensintesis, G2 = Bersedia, M = Membiak!"

🧬 Mitosis vs MeiosisMitosis lwn Meiosis

FeatureCiriMitosisMitosisMeiosisMeiosis
DivisionsPembahagian12
Daughter cellsSel anak2 (identical, diploid)2 (serupa, diploid)4 (different, haploid)4 (berbeza, haploid)
Occurs inBerlaku dalamSomatic (body) cellsSel somatik (badan)Gonads (testes/ovaries)Gonad (testis/ovari)
Crossing overPindah silangNoTidakYes (Prophase I)Ya (Profasa I)
PurposeTujuanGrowth, repairPertumbuhan, pembaikanSexual reproductionPembiakan seksual
🔑 PMAT:🔑 PMAT: Prophase → Metaphase → Anaphase → Telophase (for both!)Profasa → Metafasa → Anafasa → Telofasa (untuk kedua-duanya!)
Mitosis vs Meiosis — Visual Comparison (2n=4) MITOSIS MEIOSIS Parent Cell (2n=4) — 4 chromosomes Parent Cell (2n=4) — 4 chromosomes 1 Division 2 Divisions 2 cells (2n=4) — Identical After Meiosis I: 2 cells (n=2) 2n=4 2n=4 n=2 n=2 n=2 n=2 2 identical diploid — Growth & repair 4 different haploid — Gametes SPM Key: Crossing over only in Meiosis I → genetic variation

Figure: Mitosis (2 identical) vs Meiosis (4 different) — 2n=4 comparison Rajah: Mitosis (2 serupa) vs Meiosis (4 berbeza) — perbandingan 2n=4

🔬 Stages of Mitosis (PMAT)🔬 Perkembangan Mitosis (PMAT)

ProphaseNucspindlecondense MetaphaseNucEq Anaphase TelophaseNuccell plate Cytokinesis

Fig A: Mitosis Stages — PMAT + CytokinesisRajah A: Perkembangan Mitosis — PMAT + Sitokinesis

🔬 Meiosis I & II🔬 Meiosis I & II

Prophase I✂️ crossing over Metaphase I Anaphase I Telophase Inn Meiosis II (similar to mitosis, but haploid cells) Prophase II Metaphase II Anaphase II Telophase II

Fig B: Meiosis I (reduction) & II (equational) — produces 4 haploid gametesRajah B: Meiosis I (pengurangan) & II (ekuasi) — menghasilkan 4 gamet haploid

🔬 Chromosome Number Through Mitosis & Meiosis (2n=4)🔬 Nombor Kromosom Melalui Mitosis & Meiosis (2n=4)

Parent2n = 4 Mitosis1 division2n2n2 diploid Meiosis2 divisionsnnnn4 haploid

Fig C: Chromosome tracking — mitosis maintains 2n, meiosis reduces to nRajah C: Penjejakan kromosom — mitosis mengekalkan 2n, meiosis mengurangkan kepada n

⚡ Quick CheckSemakan Cepat

Which process produces 4 genetically different haploid cells?Proses manakah yang menghasilkan 4 sel haploid yang berbeza secara genetik?

AMitosisMitosis
BMeiosisMeiosis
CCytokinesisSitokinesis
DInterphaseInterfasa

🇲🇾 Malaysian ContextKonteks Malaysia

Malaysia has high breast and cervical cancer rates — understanding cell division helps explain how cancer develops from uncontrolled cell division. Early detection saves lives!Malaysia mempunyai kadar kanser payudara dan serviks yang tinggi — memahami pembahagian sel membantu menjelaskan bagaimana kanser berkembang daripada pembahagian sel yang tidak terkawal. Pengesanan awal menyelamatkan nyawa!

📋 SPM Practice📋 Latihan SPM

SPM Practice QuestionSoalan Latihan SPM

Explain the importance of meiosis in producing genetic variation. [4 marks]Terangkan kepentingan meiosis dalam menghasilkan variasi genetik. [4 markah]

📌 Exam Tip:📌 Tips Peperiksaan: Mention crossing over (Prophase I) + independent assortment (Metaphase I)Nyatakan pindah silang (Profasa I) + susunan bebas (Metafasa I)

🃏 FlashcardsKad Flash

Mitosis produces?Mitosis menghasilkan?
2 identical diploid cells2 sel diploid yang serupa
Meiosis produces?Meiosis menghasilkan?
4 different haploid cells4 sel haploid yang berbeza
Crossing over occurs in?Pindah silang berlaku dalam?
Prophase I (Meiosis)Profasa I (Meiosis)
Cancer is?Kanser ialah?
Uncontrolled cell divisionPembahagian sel yang tidak terkawal
Human diploid number?Bilangan diploid manusia?
2n = 46 chromosomes2n = 46 kromosom