The condensed version of this chapter for last-minute revision: every mode, definition and diagram
label in one place. The full detailed notes are available separately.
1 Modes of Asexual Reproduction, at a Glance
Asexual Reproduction
FissionAmoeba (any plane), Leishmania (fixed orientation), Plasmodium (multiple)
FragmentationSpirogyra
RegenerationHydra, Planaria
BuddingHydra
Vegetative propagationpotato, Bryophyllum, sugarcane, rose, grapes
Spore formationRhizopus
2 All Definitions in One Place
Definitions worth memorising
VariationSmall, inheritable difference from imperfect DNA copying, the basis of evolution
Binary fissionSplitting into two equal halves
Multiple fissionSplitting into many daughter cells at once (Plasmodium)
FragmentationA simple body breaks up; each piece grows into a new individual
RegenerationA cut piece regrows a whole new organism; NOT the same as reproduction
BuddingA new individual grows as an outgrowth at one site, then detaches
Vegetative propagationA new plant grows from a root, stem or leaf, not a seed
Spore formationThick-walled spores in sporangia grow into new individuals (Rhizopus)
MeiosisCell division producing germ-cells with half the normal chromosome number
PollinationTransfer of pollen from stamen to stigma; self or cross
FertilisationFusion of the male germ-cell with the egg cell in the ovule, forming a zygote
PubertyThe period when reproductive tissues mature, once body growth slows down
TestosteroneHormone from the testes; regulates sperm formation and puberty changes in boys
PlacentaDisc in the uterine wall exchanging glucose, oxygen and waste between mother and embryo
MenstruationMonthly shedding of the unused, thickened uterine lining as blood and mucus
ContraceptionMethods to prevent pregnancy: mechanical barrier, hormonal, IUD, or surgical
3 Flower Parts
| Part | Sex | Function |
|---|---|---|
| Stamen (filament + anther) | Male | Produces pollen grains |
| Stigma | Female | Sticky tip, receives pollen |
| Style | Female | Connects stigma to ovary |
| Ovary (contains ovules) | Female | Each ovule has an egg cell |
Common Mistake
Pollination (pollen reaching the stigma) and fertilisation (germ-cell fusion in the ovule) are
NOT the same step.
4 Human Reproductive Organs
| System | Organs, in order |
|---|---|
| Male | Testes (in scrotum) → vas deferens → urethra (shared with urine); seminal vesicle + prostate add fluid |
| Female | Ovaries (1 egg/month) → fallopian tube (oviduct) → uterus → cervix → vagina |
5 Key Numbers
1egg released per month
~9months of gestation
2-8days a period lasts
~1day an unfertilised egg survives
6 Reproductive Health
| Category | STI examples / method |
|---|---|
| Bacterial STIs | Gonorrhoea, syphilis |
| Viral STIs | Warts, HIV-AIDS |
| Mechanical barrier | Condom, vaginal covering |
| Hormonal | Oral pills (change hormone balance) |
| IUD | Loop, copper-T |
| Surgical | Blocking vas deferens (male) or fallopian tube (female) |
Quick Revision: read this the night before the exam
- Asexual (one parent): fission, fragmentation, regeneration, budding, vegetative propagation, spore formation
- Sexual (two parents) uses meiosis and gives more variation
- Flower: stamen (male) and pistil (female); pollination happens before fertilisation, they are not the same
- Male: testes (scrotum) → vas deferens → urethra. Female: ovaries → fallopian tube → uterus → cervix → vagina
- Menstruation: unfertilised egg dies in ~1 day, lining sheds, menstruation lasts 2-8 days
- Contraception: barrier, hormonal, IUD, surgical – four categories, one exam favourite
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