Human Reproduction Flashcards

Cell Definition: The basic unit of life.
Organelle Specificity in Eukaryotic Cells:
- Animal Cells: Exclusively contain lysosomes and centrioles.
- Plant Cells: Exclusively contain chloroplasts and a cell wall.

Gonads: Primary reproductive organs responsible for gamete and hormone production:
- Male Gonads: Testes, which produce sperm and testosterone.
- Female Gonads: Ovaries, which produce eggs (ova) and hormones such as estrogen and progesterone.
Gametes: Sex cells involved in reproduction, consisting of sperm in males and eggs (ova) in females.
Accessory Reproductive Organs: Ducts and glands that assist in the transport and nourishment of gametes and support the developing embryo.
Secondary Sexual Characteristics: Physical traits that distinguish males from females developing during puberty (e.g., facial hair development in males, breast development in females).

Gametogenesis: The process of gamete formation, categorized into:
- Spermatogenesis: Gamete formation in males.
- Oogenesis: Gamete formation in females.
Fertilization: The union of sperm and egg, typically occurring in the Fallopian tube (oviduct).
Zygote: The single cell formed immediately after fertilization.
Embryo: The early stage of development spanning from fertilization to about $8\,\text{weeks}$ .
Implantation: The process of the embryo embedding itself into the uterine wall.
Fetus: The later stage of development extending from $8\,\text{weeks}$ of childbearing until birth.
Parturition: The biological process of childbirth.

Semen: Fluid containing sperm secreted from the male reproductive system.
Uterus: Muscular organ in females where the embryo develops.
Placenta: A structure that develops during pregnancy, connecting the developing fetus to the mother's uterine wall to allow for nutrient and waste exchange.
Umbilical Cord: Structure that connects the fetus to the placenta.
Amniotic Sac: A fluid-filled sac that cushions and protects the developing fetus.
Puberty: The period during which reproductive organs mature and secondary sexual characteristics develop.

Definition of Reproduction: The biological process by which living organisms (including animals, humans, plants, and microorganisms) form new individuals.
Primary Modes of Reproduction:
- Asexual Reproduction: A single organism produces genetically identical offspring.
- Sexual Reproduction: The formation of offspring resulting from the fusion of gametes (egg and sperm), a process termed fertilization.

Binary Fission:
- Occurs in prokaryotic microorganisms and in certain single-celled and multi-celled invertebrate organisms.
- Process: Following replication of the DNA molecule, an organism splits into $2$ separate organisms.
- Organism Examples: Amoeba, bacteria, Euglena.
Budding:
- Occurs when a new organism starts growing from the parent body in plants or animals.
- Process: The bud develops into a mature organism and may remain attached to the parent's body or break off.
- Organism Examples: Hydra, yeast.
Fragmentation (Splitting):
- Occurs when the body of an organism breaks into several parts.
- Process: Each part develops into a mature clone that is genetically and morphologically identical to the parent.
Parthenogenesis:
- A natural form of asexual reproduction in animals in which the growth and development of embryos occur without fertilization by sperm.
Spore Formation:
- Asexual mode commonly exhibited by fungi.
- Process: Spores are contained within a structure known as a sporangium, which disintegrates to release the spores into the environment.
Vegetative Reproduction (Vegetative Propagation):
- A form of asexual reproduction in plants where new independent individuals are formed without the production of seeds or spores.

External Fertilization:
- Process: Fusion of gametes occurs outside the female body.
- Specific Example: In salmon, the female deposits her ova on the riverbed; the male subsequently deposits his sperm in the water, and the sperm swim to fertilize the eggs.
Internal Fertilization:
- Process: Fusion of gametes occurs inside the female body, resulting in the formation of the zygote (fertilized egg) within the female body.

Vegetative and Protective Flowers Parts:
- Petals: Brightly colored parts that function to attract pollinators such as bees, insects, and birds.
- Sepals: Green-colored structures located beneath the petals that protect rising/developing buds.
Male Reproductive Structure (Stamen):
- Anther: Yellowish, sac-like structure involved in producing and storing pollen.
- Filament: Slender, thread-like stalk that structurally supports the anther.
Female Reproductive Structure (Pistil / Carpel / Gynaecium):
- Stigma: Topmost part or receptive tip of the carpels in the gynaecium of a flower.
- Style: Long, tube-like slender stalk connecting the stigma to the ovary.
- Ovary: Ductless reproductive gland that holds the ovules.

Number of Individuals Involved:
- Asexual Reproduction: Involves a single organism ( $1$ parent).
- Sexual Reproduction: Involves $1$ or $2$ organisms (typically $2$ parents).
Nature of Offspring:
- Asexual Reproduction: Produces offspring that are identical (clones) to the parent.
- Sexual Reproduction: Produces offspring that display a combination of characteristics from both parents.
Production of Gametes:
- Asexual Reproduction: No gametes are produced.
- Sexual Reproduction: Male and female gametes are produced.
Fusion of Gametes:
- Asexual Reproduction: No fusion of gametes occurs.
- Sexual Reproduction: Requires the fusion of male and female gametes.
Cell Division Requirements:
- Asexual Reproduction: Requires only mitotic cell divisions.
- Sexual Reproduction: Requires both meiotic and mitotic cell divisions.
Chance of Genetic Variation:
- Asexual Reproduction: Genetic variation is low and can only occur through genetic mutation.
- Sexual Reproduction: Genetic variation is high due to the genetic combination of both parents.
Methods and Types Included:
- Asexual Reproduction: Binary fission, budding, fragmentation, parthenogenesis, spore formation, and vegetative reproduction.
- Sexual Reproduction: Internal fertilization and external fertilization.