Reproduction: How Life Continues

Comprehensive vocabulary flashcards covering Chapter 11 ('Reproduction: How Life Continues') from Grade 9 Science. Topics include modes of asexual reproduction, plant floral biology, pollination and fertilisation mechanisms, animal reproductive variations, human reproductive anatomy and physiology, the menstrual cycle, pregnancy, IVF, and contraception.

Reproduction

The biological process through which living organisms produce new individuals of their own kind, ensuring the continuation of life and transmission of genetic information across generations.

Vegetative propagation

A form of asexual reproduction in plants where new individuals develop directly from vegetative or growing structures—such as stems, roots, or leaves—without seed production.

Vegetative propagation in Bryophyllum

A natural asexual process in which tiny plantlets sprout along the notched margins of the parent leaf, eventually detaching and rooting to establish independent plants.

Cutting

An artificial vegetative propagation technique in which a piece of stem bearing nodes and internodes is removed and inserted into moist soil mixed with compost at an angle of $45^\circ\text{–}60^\circ$.

Grafting

A horticultural technique in which a stem portion of a desired plant variety (Plant B) is inserted and bound securely into a slit or wound of an established rooted plant (Plant A) to unite their vascular systems.

Layering

A propagation method where a flexible branch of a living shrub or tree is bent and partly buried under the soil until adventitious roots sprout from the buried section, after which it is severed from the parent.

Plant tissue culture

A laboratory method of asexual reproduction where healthy, virus-free plantlets are mass-produced on artificial nutrient media using cells harvested from the shoot tip (apical meristem).

Budding

An asexual reproductive method in which localized, repeated cell divisions on a parent organism produce an outgrowth (bud) that develops, enlarges, and eventually detaches as an independent organism.

Budding in Hydra

An asexual process in a simple multicellular animal where cells divide repeatedly at a specific site on the body wall to create a bud that matures and separates from the parent.

Spore formation

An asexual mode of reproduction in fungi (such as Rhizopus and Aspergillus) where millions of lightweight, microscopic, single-celled reproductive units develop inside swollen sacs or hyphal vesicles and disperse through air currents.

Mitosis

The central cell-division mechanism of asexual reproduction in which a parent cell divides to generate two daughter cells, each with an identical set and number of chromosomes, producing clones.

Meiosis

A specialized reductional cell division in sexually reproducing organisms that reduces the chromosome number by half (from diploid to haploid) to create gametes, preventing chromosome duplication across generations.

Gametes

Specialized haploid reproductive cells (sperm and eggs in animals; pollen-borne male gametes and ovule egg cells in plants) that contain a single set of chromosomes and fuse during fertilisation.

Angiosperms

The diverse taxonomic group of flowering plants in which specialized floral structures act as the organs of sexual reproduction.

Sepal

The outermost green floral leaf that forms the protective outer whorl surrounding and shielding petals and inner reproductive organs while in the bud stage.

Petal

The colourful inner floral leaf situated within the sepals, adapted through colour, scent, and nectar to visually and chemically attract insect or bird pollinators.

Stamen

The male reproductive organ of an angiosperm flower, made up of a slender supporting filament and a terminal anther that manufactures pollen grains.

Pistil

The female reproductive organ of a flower located at its center, consisting of an apical receptive stigma, a connecting style tube, and a basal swollen ovary containing ovules.

Floral anatomy (Longitudinal Section)

The structural organization of a complete flower displaying its four concentric whorls: outer calyx (sepals), corolla (petals), male androecium (stamens), and central female gynoecium (pistil).

Pollination

The mechanical or biological transfer of pollen grains from the anther to the receptive stigma of a flower, serving as the required precursor for fruit and seed production.

Self-pollination

The transfer of pollen grains from an anther to the stigma of the same flower or another flower situated on the identical parent plant.

Cross-pollination

The transfer of pollen grains from the anther of a flower on one individual to the stigma of a flower on a different plant of the same species.

Pollination mechanisms

The distinction between self-pollination (pollen delivery within the same plant) and cross-pollination (pollen delivery across distinct plants of the same type via external agents).

Fertilisation (in plants)

The fusion of the male gamete with the female egg cell inside the ovule after traversing the length of the style via a pollen tube, resulting in a diploid zygote.

Pollen tube germination and fertilisation

The sequence wherein a pollen grain germinates on the stigma surface, extends a cytoplasmic tube through style tissue, and delivers male germ cells into the ovarian ovule to fertilise the egg.

Zygote

The initial diploid cell formed immediately upon the successful fusion of male and female gametes during fertilisation, which subsequently develops into an embryo.

P. Maheshwari

The scientist celebrated as the 'Father of Indian Embryology' who established in-vitro fertilisation in flowering plants and wrote the classic text 'An Introduction to the Embryology of Angiosperms' (1950).

Artificial hybridisation

A plant breeding procedure wherein immature stamens are excised from flower buds, the buds are enclosed in muslin bags to block self-pollination, and desired pollen is manually transferred onto stigmas.

External fertilisation

A reproductive strategy common among aquatic animals like frogs and fish where large quantities of eggs and sperm are discharged directly into surrounding water for fertilisation outside the body.

Internal fertilisation

A reproductive strategy characteristic of reptiles, birds, and mammals where male gametes are introduced inside the female genital tract, giving greater physical protection to the fertilised zygote.

Larva

An active, free-living intermediate juvenile stage in the development of certain animals (such as butterflies and frogs) adapted primarily for nutritional feeding before metamorphic transition into adult form.

Butterfly life cycle

The complete metamorphosis sequence comprising four distinct morphological stages: egg, feeding larva (caterpillar), non-feeding encased pupa (chrysalis), and adult emergence.

Scrotum

An external cutaneous pouch housing the testes outside the human abdominal cavity, providing an environment slightly cooler than regular body temperature to enable viable sperm production.

Vas deferens

A muscular conduit that transports mature sperm from each testis up toward the urethra in the male reproductive system.

Male reproductive system

The male human organ system consisting of the scrotal testes, vas deferens ducts, accessory fluid-secreting glands (seminal vesicles and prostate gland), urethra, and penis.

Ovaries

The paired female primary gonads responsible for generating female germ cells (eggs) and synthesizing reproductive hormones that govern pubertal development and menstrual cyclicity.

Fallopian tubes

Pair of oviduct ducts extending from near the ovaries to the upper uterus that receive the ovulated egg and serve as the standard biological site of fertilisation.

Uterus

The hollow, pear-shaped muscular pelvic organ in human females whose thickened vascular endometrium receives, implants, and nourishes the developing embryo and foetus throughout gestation.

Cervix

The narrow inferior neck and opening of the uterus that connects the uterine lumen directly to the vaginal birth canal.

Female reproductive system

The internal female reproductive structure comprising bilateral ovaries, fallopian tubes (oviducts), the central muscular uterus, cervix, and the vagina.

Gametogenesis

The biological pathway of gamete production taking place in the testes and ovaries, wherein diploid precursor cells undergo meiotic division to produce haploid sperm or eggs.

Ovulation

The mid-cycle physiological event, typically occurring around day 14 of a standard 28-day menstrual cycle, in which an ovary releases a single mature egg into the oviduct.

Implantation

The physiological embedding of the dividing, travel-ready embryo into the vascularized inner lining of the uterus, establishing nutritional contact and marking the start of pregnancy.

In-vitro Fertilisation (IVF)

An assisted reproductive procedure wherein extracted female eggs and male sperm are united outside the maternal body inside a culture dish, after which resulting embryos are transferred into the uterus.

Subhash Mukhopadhyay

The Kolkata-based physician-scientist who created India's first test tube baby, Kanupriya Agarwal (nicknamed Durga), via innovative in-vitro fertilisation in 1978.

Menstruation

The cyclical breakdown and vaginal discharge of the unneeded blood-rich uterine endometrium and unfertilised egg, usually spanning 3 to 7 days in cycles recurring every $21\text{–}35$ days.

Foetus

The anatomical designation for a developing human organism in the uterus from approximately the ninth week of pregnancy until delivery.

ASHA workers

A cadre of more than 10 lakh trained community health activists under India's National Health Mission who promote rural sanitation, immunisation, maternal well-being, and contraceptive awareness.

Sexually Transmitted Infections (STIs)

Contagious diseases acquired through sexual contact, including bacterial and viral conditions such as gonorrhoea, syphilis, genital warts, herpes, and HIV.

Intra-Uterine Device (Copper-T)

A reversible contraceptive device placed by medical professionals into the uterine cavity to impede sperm movement and prevent fertilisation.

Centchroman

The world's first non-steroidal and non-hormonal oral contraceptive pill, engineered by scientists at the Central Drug Research Institute (CDRI), Lucknow, and administered once weekly without conventional hormonal side effects.

Reproduction

The biological process by which living beings produce new individuals of their own kind, ensuring the continuation of life on Earth.

Asexual Reproduction

A mode of reproduction involving a single parent that produces offspring genetically identical to the parent.

Sexual Reproduction

A mode of reproduction involving two parents where offspring inherit a combination of characteristics from both individuals, generating variation.

Vegetative Propagation

A form of asexual reproduction in plants where new individuals develop directly from vegetative parts such as stems, roots, or leaves without the formation of seeds.

Cutting

An artificial vegetative propagation method in which a shoot cutting containing nodes and internodes is inserted into compost-mixed soil at an angle of about $45^\circ\text{–}60^\circ$ to sprout a new plant.

Grafting

A propagation technique where a stem piece from one variety (Plant B) is inserted and fitted into a slit cut on a rooted plant of another variety (Plant A) and wrapped to allow healing and joint growth.

Layering

A propagation method in which a flexible, thin twig of a shrub or tree is bent and buried in the soil until adventitious roots develop after $10\text{–}15\text{ days}$, after which it is severed from the parent.

Plant Tissue Culture

An asexual propagation technique where mass-produced healthy plantlets are regenerated from shoot apical meristems in sterile conditions, eliminating viral infections and ensuring high yields in crops like banana.

Budding

An asexual reproductive process where repeated cell divisions at a specific body site produce a small outgrowth or bud that enlarges and detaches from the parent organism to live independently, as observed in yeast and hydra.