Reaching the Age of Adolescence Class 8 Science (Biology) in One Shot | BYJU'S - Class 8

Gametes

Male and female reproductive cells that come together to form a zygote.

Zygote

A single-cell structure formed when male and female gametes combine.

Embryo

The multicellular structure formed from the zygote.

Nucleus

The central part of a cell that contains genetic material or chromosomes.

Chromosomes

Structures found inside the nucleus that contain genetic material.

Genetic material

The information that determines an organism's traits and characteristics.

Organism

Any living thing.

Human beings

The species to which we belong.

46 chromosomes

The number of chromosomes found in human beings.

23 pairs of chromosomes

The 46 chromosomes are organized into 23 pairs.

Autosomes

The first 22 pairs of chromosomes that are common to both males and females.

S** chromosome

The 23rd pair of chromosomes that determines the s** or gender of an individual.

Zygote

The fertilized egg that develops into an individual.

XY

The combination of sex chromosomes that typically determines a male or a boy.

XX

The combination of sex chromosomes that typically determines a female or a girl.

Sex determination

The process or phenomenon by which the sex of a baby is determined.

Fertilization

The process in which one chromosome from each parent combines during reproduction.

Gametes

Reproductive cells, such as eggs and sperm, that have half the number of chromosomes compared to other cells in the body.

Sperm

The male gamete, which contains 23 chromosomes.

Zygote

The cell formed by the fusion of an egg and a sperm, containing 46 chromosomes.

22 plus X

The combination of chromosomes in an egg, where 22 chromosomes are paired and one is an X chromosome.

22 plus Y

The combination of chromosomes in a sperm, where 22 chromosomes are paired and one is a Y chromosome.

Stereotypical

Having a fixed or oversimplified idea or image of a particular group or person.

Identical twins

Twins that develop from a single fertilized egg and share the same genetic material.

Fraternal twins

Twins that develop from two separate fertilized eggs and have different genetic material.

Transgender

Individuals who identify themselves as a gender different from the one they were assigned at birth.

Infancy

The stage of life when a person is a young baby.

Childhood

The stage of life between infancy and adolescence, where the body is not capable of reproduction.

Adolescence

The stage of life between childhood and adulthood, typically during the teenage years.

Early adulthood

The stage of life in the early twenties, where the body and mind become capable of reproduction.

Middle age

The stage of life between early adulthood and old age.

Old age

The stage of life when a person is elderly and typically experiences physical and cognitive decline.

Adolescence

The transitional stage between childhood and adulthood where reproductive maturity is attained.

Puberty

The point in life or time in life where the body becomes sexually mature and undergoes changes.

Reproductive maturity

The state of being capable of sexual reproduction.

Sexual maturity

The state of being physically and biologically ready for sexual reproduction.

Physical changes

The bodily changes that occur during adolescence, including growth spurts, development of secondary sexual characteristics, and changes in body shape and size.

Emotional changes

The psychological and emotional changes that occur during adolescence, including increased independence, mood swings, and the development of a personal identity.

Secondary sexual changes

The physical changes that occur during puberty, such as the development of breasts in females and the growth of facial hair in males.

Physical changes

Changes that can be observed in the physical features or structures of an object or organism.

Increase in height

The change in height observed in individuals as they grow, usually due to the elongation of bones.

Puberty

The stage of life when an individual attains sexual maturity.

Growth hormone

A hormone that regulates the elongation of bones and is responsible for the increase in height during puberty.

Growth spurt

A period of rapid growth observed during adolescence, characterized by an increase in the production of growth hormone.

Genetic characters

The inherited traits or characteristics passed down from parents to their offspring, which can influence an individual's maximum height.

Change in shape

A physical change that involves a transformation in the form or structure of an object or organism.

Change in shape

The physical change observed in boys and girls during puberty where boys develop broader shoulders and chest region, while girls experience widening of the hip region.

Voice box

Also known as the larynx, it is the organ responsible for producing sound and undergoes development during puberty, resulting in changes in voice.

Adam's Apple

A protrusion in the neck region caused by the enlargement of a specific cartilage in the voice box, mainly observed in boys during puberty.

Gland

A group of cells that secrete certain chemical substances.

Sweat glands

Glands that produce sweat, and their increased activity during adolescence can lead to excessive sweating.

Sebaceous glands

Glands that produce sebum or oil, and their increased activity during adolescence can result in oily skin.

Pimples

Formed when the pores of the sebaceous glands get clogged, resulting in tiny bumps on the skin.

Acne

When the clogged pores become infected by bacteria, resulting in red and painful bumps on the skin.

Physical changes

Changes that occur in the body's appearance or structure.

Hormones

Chemical messengers produced by glands in the body that regulate various bodily functions.

Doubts

Questions or uncertainties about a particular topic or concept.

Gland

An organ in the body that produces and releases hormones.

Thyroid gland

A gland located in the neck that produces hormones that regulate metabolism.

Doubt clearing session

A dedicated time or session where questions and uncertainties are addressed and clarified.

NCRT session

A session focused on the content and concepts covered in the NCRT (National Council of Educational Research and Training) textbook.

Acne

A skin condition characterized by the presence of pimples, blackheads, and whiteheads.

Pimples

Small, inflamed bumps on the skin, often filled with pus.

Emotional changes

Changes in a person's feelings, moods, and emotions.

Emotional changes

Mental changes or changes in the mind that occur during adolescence and early adulthood. These changes include increased brain activity, mood swings, and increased curiosity and inquisitiveness.

Brain development

The expansion and development of the brain that occurs during adolescence, leading to improved brain capacity and the ability to learn and process information.

Mood swings

Fluctuations in mood and emotions that are commonly experienced during adolescence, characterized by periods of heightened happiness, low energy, and sometimes irritability or aggression.

Decision-making skills

The ability to make choices and decisions, which develops during adolescence as individuals become more independent and gain a clearer understanding of their own preferences and desires.

Aggression

Occasional displays of aggressive behavior, which can be a result of increased independence and assertiveness during adolescence. It is important to treat others with kindness and respect, even when disagreements occur.

Feelings of anxiety

Hyperactive feelings and a sense of urgency or pressure to accomplish tasks or meet expectations. It is important to open up to parents or teachers and seek support during times of anxiety.

Sexual changes

Changes that differentiate individuals as male or female, including primary sexual characteristics (development of reproductive organs) and secondary sexual characteristics (outward physical features that help identify gender).

Primary sexual characteristics

The presence and development of reproductive organs, such as testes in males and ovaries in females, which are the primary indicators of biological sex.

Secondary sexual characteristics

Outward physical features that help identify an individual as male or female, such as breast development in females and facial hair growth in males.

Sexual characteristics

The physical traits that help identify an individual as male or female.

Primary sexual characteristics

The most basic way to differentiate between males and females, based on the presence of reproductive organs.

Mammary glands

The milk-producing glands in females.

Hormones

Chemical messengers produced by endocrine glands that regulate various changes in the body.

Endocrine glands

Glands that produce hormones and release them directly into the bloodstream.

Exocrine glands

Glands that produce chemical substances and transport them to target sites through ducts.

Duct

A tube that transports substances from glands to target sites.

Receptor

A specific structure on cells that binds to hormones and allows them to pass on messages.

Sex hormones

Hormones that play a crucial role in sexual development and reproduction.

Hormones

Chemical secretions from the endocrine system.

Testosterone

Male sex hormone produced by the testes, responsible for the development of the male reproductive system and secondary sexual characteristics.

Testes

Male reproductive organs located outside the abdominal cavity and enclosed in the scrotum, responsible for the production of testosterone.

Estrogen

Female sex hormone produced by the ovaries, responsible for the development of the female reproductive system and secondary sexual characteristics.

Ovaries

Female reproductive organs located in the abdomen, responsible for the production of estrogen and progesterone.

Progesterone

Female sex hormone also known as the pregnancy hormone, necessary for the development of the embryo after implantation.

Ovulation

The process in which a mature egg is released from the ovary.

Ovulation

The release of an egg from the ovary.

Menstruation

The shedding of the inner lining of the uterus, along with the unfertilized egg, which occurs when fertilization does not take place.

Endometrium

The inner lining of the uterus.

Menstrual cycle

The cyclic process that occurs every 28 days, involving ovum development, ovulation, thickening of the uterus lining, and menstruation.

Follicles

Structures inside which the ovum develops.

Estrogen

A hormone that increases during the menstrual cycle and plays a role in ovulation and thickening of the uterus lining.

Menarche

The first menstrual cycle or menstruation that occurs in a female's life.

Reproductive phase

The phase of life when a female can reproduce.

Menopause

The cessation of the menstrual cycle, marking the end of reproductive capability in females.

Pituitary gland

Located at the base of the brain, it is known as the master gland and produces growth hormone and stimulating hormones.

Thyroid gland

Butterfly-shaped gland located in the neck region, responsible for producing thyroxine which regulates metabolic processes in the body.