How Do Organisms Reproduce? | Important terms & definitions | Class-10

Asexual Reproduction

Terms	Meaning
Asexual Reproduction:	A type of reproduction involving a single parent and does not involve the fusion of gametes.
Binary Fission:	A cell divides into two halves and each of these two halves rapidly grows into an adult. (e.g., Amoeba, Paramecium)
Multiple Fission:	Division of the nucleus into a number of daughter nuclei, followed by division of the cell body into an equal number of daughter cells, each containing a nucleus.
Fragmentation:	A method of asexual reproduction, where the matured parent organism breaks into many smaller fragments, and then each of these fragments develop into a new organism.
Regeneration:	A specialized method of asexual reproduction where a fully matured have the ability to give rise to new individual organisms from their body parts. (e.g., Hydra, Planaria, etc.)
Budding:	A type of asexual reproduction where a small outgrowth on the parent body gives rise to a new organism due to cell division at a particular site. The new organism remains attached to the parent until it is mature. (e.g., Hydra)
Vegetative Propagation:	It is a method of obtaining new plants from plants parts (such as stems, roots, and leaves), apart from the reproductive structures.
Spores:	In some fungi like Rhizopus, a small, single-celled reproductive body is formed that is resistant to adverse environmental conditions and is capable of growing into a new organism.
Hyphae:	Long, branched filamentous structure of a fungus.
Sporangia:	Structure in ferns and lower plants where the spores are formed.

Sexual Reproduction (Plants)

Terms	Meaning
Bisexual Flower:	The flower with both stamens and carpels. (Mustard, Hibiscus, Lily, Rose, Sunflower, Mango, etc.)
Unisexual Flower:	The flower with either stamens and carpels. (Pumpkin, Papaya, Watermelon, Cucumber, Maize, etc.)
Calyx:	Calyx is the outermost whorl. It consists of sepals. It protects the flower at the bud stage.
Corolla:	Corolla, the next inner whorl, consists of petals. They are brightly colored to attract the pollinators like insects.
Androecium:	The stamens are collectively called androecium, represents the male reproductive structures. Each stamen consists of a filament and an anther.
Gynoecium:	The female reproductive structures are referred to as gynoecium and is represented by pistils. All the carpels together are represented as pistil. Each carpel consists of three parts—a basal ovary, a middle portion called style and flattened disc-like sticky structure called stigma at the top of the style.
Pollen grains:	Microscopic grains released from the male part of the flower that contains the male gamete, capable of fertilizing female gamete.
Stigma:	The top sticky portion of the stamen where the pollen lands and the compatible pollen germinates.
Pollination:	The process of transfer of pollen from the male reproductive organ to the female reproductive organs of a plant, thereby enabling fertilization to take place.
Pollen tube:	The pollen tube is a tube through which male gamete from the pollen reaches the egg cell, and fertilizes it to produce seeds.
Plumule:	The primary bud of a plant embryo that gives rise to the future shoot.
Radicle:	The primary bud of a plant embryo that gives rise to the future root.
Cotyledons:	Also known as seed leaves. It remains attached to the seedling and provides nutrition till the real leaves are formed.

Sexual Reproduction (Humans)

Terms	Meaning
Sexual reproduction:	A type of reproduction that involves the fusion of gametes from two parents.
Gonads:	Organ producing reproductive cells. Male gonads: testes; Female gonads: Ovaries
Testicles / Testis (Sing.)/ Testes (Plu.):	Two ball-like glands inside the scrotum that produce sperm.
Ovary:	The organ of the female reproductive system that produces the egg.
Sperm:	Reoroductive cells of human males produced in the testes.
Prostate gland:	Part of the male reproductive system that secretes a fluid that nourishes and protects sperm.
Seminal vesicle:	This gland release the liquid that mixes with sperm to form semen.
Bulbourethral glands	This paired gland releases a liquid that neutralizes any residual acidity in the urethra. The now neutralized urethra make it more suitable environment for the sperm to travel in.
Vas deferens:	It bring the sperm from the testes to the seminal vesicles
Ovum:	The egg cell of human females.
Abortion:	Also referred to as medically terminated pregnancies (MTP). It is normally performed before the 20th week of gestation.
Egg cell:	The female gamete that is haploid in nature.
Fallopian tube:	The tube-like structure along which eggs travel from the ovaries to the uterus. It is present in a pair of human females.
Ejaculation:	The release of semen from the penis.
Semen:	Fluid containing the sperm that is ejaculated during sexual excitement. Semen is composed of secretions from the seminal vesicles, prostate gland, and Cowper’s glands (bulbourethral glands).
Fertilization:	The process of fusion of male and female gametes.
Implantation:	The embedding of the developing embryo to the uterine walls.
Zygote:	The cell produced as a result of the fusion of the male and female gamete.
Embryo:	The organism in the early stages of growth and differentiation from fertilization to, in humans, the beginning of the third month of pregnancy, after that point in time it is termed a fetus
Morula	A solid mass of cells (12-16 cells), that results due to rapid mitosis cell division of the fertilized egg.
Blastula	Blastula is the next stage after the morula during the postfertilization events in humans. It is a hollow sphere of cells with space inside called the blastocoel.
Parturition	The process of giving birth to young ones.
Placenta:	The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, provide thermo-regulation to the fetus, waste elimination, and gas exchange via the mother’s blood supply, fight against internal infection and produce hormones to support the pregnancy. The placenta provides oxygen and nutrients to growing babies and removes waste products from the baby’s blood. The placenta attaches to the wall of the uterus, and the baby’s umbilical cord.
Umbilical Cord	Umbilical cord develops from the placenta and is the connection between the mother and the baby.
Scrotum:	The sac like structure that houses the pair of testes and also provides the required temperature for the development of sperm.
Adolescence:	The period of physical and emotional change between the beginning of puberty and early adulthood
Urethra:	These are the tube-like structures that connect the urinary bladder to the external part of the body for the removal of urine.
Uterus:	It is the pear-shaped structure in the female reproductive system, that is responsible for the development of the embryo and fetus during pregnancy.
Gestation period:	The development process of the human inside the womb between conception and birth.
Cervix:	The narrow lower part of the uterus that connects the uterus to the vagina.
Endometrium:	Innermost layer of the uterus.
Puberty:	It refers to the stage of human development wherein the person first becomes capable of sexual reproduction. It is marked by the development of secondary sex characteristics, the maturation of the genital organs, and the beginning of menstruation in females.
Menstruation:	The release of blood, mucus, and tissues out of the uterus through the vagina that usually lasts from three to five days every month.
Menstrual Cycle:	A complete cycle of ovulation and menstruation.
Menarche:	The first occurrence of menstruation.
Menopause:	Menopause is the time in a woman’s life when her menstruation stops permanently, and can no longer become pregnant
Contraception:	Prevention of pregnancies.
Barrier Methods:	It is a method of contraception to prevent pregnancy by blocking the entrance of sperm, physically or chemically, into the uterus. Cervical caps, condoms, diaphragms, female condoms, spermicides are some of the examples.
Spermicides:	Chemicals used to destroy the sperms to prevent pregnancies.
IUCD	Intra Uterine Contraceptive Devices. These are a long lasting reversible method of birth control. Commonly IUCD’s are copper-releasing IUD (CuT, Cu7, Multiload 375); hormone releasing IUD (Progestasert, LNG-20).