🌸 Sexual Reproduction in Flowering Plants
| Category / Mechanism | NCERT Examples | Key High-Yield Feature / Ploidy |
|---|---|---|
| Pollen Viability | • Rice, Wheat: 30 minutes • Rosaceae, Leguminosae, Solanaceae: Months | Viability depends on temperature and humidity. |
| Pollen Allergy | Parthenium (Carrot grass) | Imported with wheat; causes chronic respiratory disorders. |
| Largest / Tallest Flower | Amorphophallus | Flower is 6 feet high; provides safe egg-laying site for insects. |
| Obligate Symbiosis | Yucca plant and Pronuba Moth | Neither species can complete its life cycle without the other. |
| Anemophily (Wind) | Grasses, Corn cob (Maize) | Tassels are stigmas and styles; pollen is light and non-sticky. |
| Hydrophily (Water) | • Marine: Zostera (Sea grasses) • Fresh water: Vallisneria, Hydrilla | Vallisneria uses epihydrophily (surface); Zostera pollen is ribbon-like. |
| Insect Pollinated Water Plants | Water Hyacinth (Eichhornia), Water Lily | Exposed above water level; pollinated by insects or wind. |
| Cleistogamous Flowers | Viola (Common pansy), Oxalis, Commelina | Invariably autagamous; produce assured seed-set without pollinators. |
| Non-albuminous (Exalbuminous) | Pea, Groundnut, Beans | Endosperm is completely consumed during embryo development. |
| Albuminous (Endospermic) | Wheat, Maize, Barley, Castor, Sunflower | Retains a part of endosperm as it is not completely used up. |
| Perisperm (Persistent Nucellus) | Black Pepper, Beet | Residual, persistent nucellus inside the seed. |
| False Fruits | Apple, Pear, Strawberry, Cashew | Thalamus contributes to fruit formation along with the ovary. |
| Parthenocarpic Fruits | Banana | Fruits develop without fertilisation; seedless. |
| Apomixis (Seed without fertilisation) | Asteraceae family, Grasses | Mimics sexual reproduction but is a form of asexual reproduction. |
| Polyembryony | Citrus fruits, Mango | Occurrence of more than one embryo in a seed. |
🤰 Human Reproduction (Ploidy & Hormonal Landmarks)
| Stage / Cell Type | Ploidy Level | Key NCERT Value / Detail |
|---|---|---|
| Spermatogonia / Oogonia | Diploid (\(2n\)) | Stem cells found in seminiferous tubules and fetal ovaries. |
| Primary Spermatocyte / Oocyte | Diploid (\(2n\)) | Undergo Meiosis-I to form secondary stages. |
| Secondary Spermatocyte / Oocyte | Haploid (\(n\)) | Secondary oocyte is arrested at Metaphase-II until fertilisation. |
| Spermatid / Spermatozoa / Ovum | Haploid (\(n\)) | Morphologically mature gametes. |
| Semen Output per Ejaculation | 200 to 300 Million Sperm | For normal fertility: 60% must have normal shape/size; 40% vigorous motility. |
| Menstrual Phase Details | Days 1–5 | Breakdown of Endometrium lining and its blood vessels. |
| LH Surge | Middle of cycle (~Day 14) | Rapid secretion of LH induces rupture of Graafian follicle (Ovulation). |
| Corpus Luteum Function | Secretes Progesterone | Essential for maintenance of endometrium during pregnancy. |
| Placental Endocrine Hormones | hCG, hPL, Progesterone, Estrogens | hCG, hPL, and Relaxin are produced in women only during pregnancy. |
| Colostrum | First milk | Rich in IgA antibodies; provides passive immunity to the newborn. |
💊 Reproductive Health (Contraceptive Methods & ART)
| Contraceptive Category | NCERT Examples | Working Mechanism / Composition |
|---|---|---|
| Natural Methods | Periodic abstinence, Coitus interruptus, Lactational amenorrhea | Lactational amenorrhea is effective up to a maximum of 6 months post-partum. |
| Barrier Methods | Condoms, Diaphragms, Cervical caps, Vaults | Diaphragms/caps are reusable and block sperm entry through the cervix. |
| Non-Medicated IUD | Lippes loop | Increases phagocytosis of sperms within the uterus. |
| Copper-Releasing IUD | CuT, Cu7, Multiload 375 | \(Cu^{2+}\) ions suppress sperm motility and fertilising capacity. |
| Hormone-Releasing IUD | Progestasert, LNG-20 | Makes the cervix hostile to sperm and uterus unsuitable for implantation. |
| Oral Contraceptive Pill (Steroid) | Mala-D, Mala-N | Taken daily for 21 days; inhibits ovulation and implantation. |
| Non-Steroidal Pill | Saheli | Developed by CDRI, Lucknow; once-a-week pill with very few side effects. |
| Sterilization (Surgical) | • Vasectomy: Males • Tubectomy: Females | Terminal method; vas deferens or fallopian tubes are cut and tied. |
| ZIFT (Zygote Intra Fallopian Transfer) | Embryo up to 8 blastomeres | Transferred directly into the fallopian tube. |
| IUT (Intra Uterine Transfer) | Embryo with more than 8 blastomeres | Transferred directly into the uterus to complete development. |
| GIFT (Gamete Intra Fallopian Transfer) | Transfer of an ovum | For females who cannot produce ova but can provide environment. |
| ICSI (Intra Cytoplasmic Sperm Injection) | Specialized lab procedure | Sperm is directly injected into the cytoplasm of the ovum. |