IP Biology Notes: Reproduction (Upper Sec 13)
Free IP Biology notes on asexual and sexual reproduction, meiosis and mitosis, plant and human reproduction, and STDs for Sec 3 to Sec 4.
Use this as a free IP Biology notes chapter on reproduction for Year 3 to Year 4. It keeps the IP pacing while reinforcing the 6093 biology foundations most schools test through DBQs, diagrams, and practical explanations.
Status: SEAB O-Level Biology 6093 syllabus (exams from 2026) checked 2025-11-30 - scope unchanged; remains the reference for this note.
The core idea is simple: Reproduction questions compare how new individuals are made.
Use it as a working check: Asexual reproduction uses mitosis and makes clones. Sexual reproduction uses meiosis, gametes, fertilisation, and variation.
Then go one layer deeper: Example: pollination is pollen transfer to the stigma. Fertilisation is fusion of nuclei inside the ovule, so use the terms separately.
What you must know
- Asexual reproduction produces genetically identical offspring; mitosis makes 2 identical diploid cells for growth/repair/asexual reproduction.
- Sexual reproduction uses meiosis to form haploid gametes (halves chromosome number); fusion restores diploid zygote; leads to variation (independent assortment/crossing over conceptually).
- Plants: flower parts (stamen, carpel, petals, sepals); insect vs wind-pollinated features (petals, scent, pollen grain traits); pollination vs fertilisation; pollen tube growth to ovule.
- Humans: male (testes, sperm ducts, prostate) and female (ovaries, oviducts, uterus, cervix, vagina) systems; menstrual cycle hormones (oestrogen, progesterone) and ovulation timing; fertilisation in oviduct; implantation in uterus; placenta/umbilical cord for exchange; amniotic fluid protection.
- STDs: HIV transmission (blood, sexual fluids, mother-to-child), reduces immunity; prevention via condoms, screened blood, no shared needles.
Detailed notes
- Asexual vs sexual: asexual quick, no gametes, clones (no variation except mutation); sexual slower, uses gametes, increases variation (independent assortment/crossing over conceptually).
- Mitosis: growth/repair/asexual reproduction; two identical diploid daughter cells. Meiosis: in gonads to form haploid gametes; halves chromosome number; leads to genetic variation.
- Flower structures: stamen (anther + filament), carpel (stigma/style/ovary), petals/sepals. Insect vs wind pollination features (colour/scent/nectar vs exposed anthers/feathery stigmas, pollen traits).
- Pollination vs fertilisation: pollination = transfer of pollen to stigma; fertilisation = male nucleus fuses with ovule nucleus. Pollen tube grows to ovule for fertilisation.
- Human reproduction: sperm made in testes (in scrotum); oviduct is fertilisation site; implantation in uterine lining; placenta for exchange (O₂, nutrients in;
