Olympiad Test: Reaching The Age Of Adolescence - Class 8 MCQ

The larynx, commonly known as the voice box, is located at the top of the neck in tetrapods. It plays a crucial role in:

• Breathing
• Sound production
• Protecting the trachea from food aspiration

The sound produced by the larynx varies based on the position of the tongue, lips, mouth, and pharynx. During swallowing, the tongue moves backward, causing a flap called the epiglottis to cover the laryngeal opening, preventing food from entering the airway.

In boys, the larynx grows larger during puberty, leading to noticeable changes in voice, often resulting in a deeper tone. This growth can cause temporary hoarseness as the muscles of the voice box adjust.

Explanation:

The correct answer is B: Female gamete.

Reasoning:

• Gametes are reproductive cells involved in sexual reproduction.
• There are two types of gametes: sperm (male) and eggs (female).
• Sperm is produced in the male reproductive system, specifically in the testes.
• Eggs, also known as ova or oocytes, are produced in the female reproductive system, specifically in the ovaries.
• During sexual reproduction, a sperm and an egg fuse in a process called fertilisation, forming a zygote that develops into an embryo.

Thus, based on the understanding of gametes and their roles, the correct answer is B: Female gamete.

Thyroxine is produced by the thyroid gland.
The thyroid gland is a butterfly-shaped gland located in the front of the neck. It is responsible for producing and releasing thyroid hormones, including thyroxine (also known as T4). Thyroxine is an important hormone that plays a crucial role in regulating metabolism and growth.
Key points:
- Thyroxine is produced by the thyroid gland.
- The thyroid gland is located in the front of the neck.
- It is responsible for regulating metabolism and growth.
- Thyroxine is a crucial hormone for the body's overall functioning.
- The production and release of thyroxine are regulated by the pituitary gland, which produces thyroid-stimulating hormone (TSH) to stimulate the thyroid gland.
- The adrenal gland produces other hormones, such as cortisol and adrenaline, but not thyroxine.
- The testes in males are responsible for producing testosterone, not thyroxine.
In summary, thyroxine is produced by the thyroid gland, and it plays a vital role in regulating metabolism and growth in the body.

Chromosomes in Human Cells:

• Chromosomes are thread-like structures in the nucleus of cells that carry genetic information.
• They consist of DNA and proteins, containing genes that influence an individual's traits.
• Humans have two types of chromosomes: autosomes and sex chromosomes.

Autosomes:

• Autosomes are non-sex chromosomes that determine most traits.
• There are 22 pairs of autosomes in a human cell.

Sex Chromosomes:

• Sex chromosomes determine an individual's sex.
• Humans have two sex chromosomes: X and Y.
• Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).

Total Number of Chromosomes:

• The total number of chromosomes in a human cell is the sum of autosomes and sex chromosomes.
• With 22 pairs of autosomes and one pair of sex chromosomes, there are a total of 23 pairs.
• Each pair consists of two chromosomes, one from each parent.

Therefore, the correct answer is A: 23.

Explanation:

Initially, girls grow faster than boys due to several factors:

• Hormonal Differences: Girls experience growth spurts earlier because of different hormone levels.
• Bone Growth: Girls' bones mature faster than boys' during puberty, contributing to their early growth.
• Puberty Timing: Girls typically enter puberty before boys, leading to significant growth.
• Genetic Factors: Genetics can influence growth rates, with girls often inheriting genes for faster growth.

While girls may initially grow faster, boys usually catch up and often surpass girls in height during adolescence.

Period of maturity of reproductive organs
The period of maturity of reproductive organs is called adolescence period. During this time, the reproductive organs undergo significant development and become capable of sexual reproduction. Here are the key points to explain this in detail:
1. Adolescence period:
- This is the stage of life between childhood and adulthood.
- It is characterized by rapid physical, psychological, and emotional changes.
- Generally, it starts around the age of 10-12 in girls and 12-14 in boys.
- During this period, the reproductive organs reach their full development and become functional.
2. Development of reproductive organs:
- In girls, the reproductive organs, including the uterus, ovaries, and fallopian tubes, undergo development and maturation.
- The onset of menstruation, or the first menstrual period, marks the beginning of the ability to conceive.
- Menstruation is the shedding of the uterine lining and the release of an egg from the ovaries.
- In boys, the testes enlarge and begin to produce sperm, marking the onset of fertility.
3. Physical and hormonal changes:
- Along with the development of reproductive organs, adolescence is also characterized by secondary sexual characteristics.
- Girls experience breast development, widening of hips, and the growth of pubic and underarm hair.
- Boys undergo voice deepening, growth of facial and body hair, and an increase in muscle mass.
- Hormones such as estrogen and testosterone play a crucial role in these changes.
4. Importance of adolescence period:
- The adolescence period is essential for the continuation of the human species through reproduction.
- It is a critical time for sexual and reproductive health education to ensure safe and responsible behavior.
- Adolescents need support and guidance to navigate the physical and emotional changes they experience.
In conclusion, the period of maturity of reproductive organs is called the adolescence period. It is a time of significant physical and hormonal changes, marking the development and functionality of the reproductive system.

Explanation:
Fertilisation is the process by which a sperm cell fuses with an egg cell, resulting in the formation of a zygote. This process is essential for sexual reproduction in many organisms, including humans.
Here is a detailed explanation of the options provided:
A. To produce sperms:
- Sperm production, also known as spermatogenesis, occurs in the testes of male organisms.
- Spermatogenesis involves the division and differentiation of germ cells to produce mature sperm cells.
- While sperm production is a part of the reproductive process, it is not the sole purpose of fertilisation.
B. To produce eggs:
- Egg production, also known as oogenesis, occurs in the ovaries of female organisms.
- Oogenesis involves the development and maturation of egg cells.
- While egg production is a part of the reproductive process, it is not the sole purpose of fertilisation.
C. Fusion of sperms and eggs:
- Fertilisation involves the fusion of a sperm cell (carrying genetic material from the male) with an egg cell (carrying genetic material from the female).
- This fusion leads to the formation of a zygote, which is the first cell of a new individual.
- Fertilisation is the crucial step that allows for the combination of genetic material from both parents, resulting in genetic diversity.
D. All of these:
- The correct answer is option C, "Fusion of sperms and eggs."
- Fertilisation involves both the production of sperm and eggs, as well as their fusion to form a zygote.
- Therefore, option D is the most accurate answer.
In conclusion, fertilisation is the process of the fusion of sperm and egg cells, leading to the formation of a zygote. While the production of sperm and eggs is a part of the reproductive process, fertilisation is the specific event where genetic material from both parents combines to create a new individual.

The correct answer is A. The puberty age in females typically occurs between 10 to 12 years.

During this stage, significant changes happen in the body, marking the transition from childhood to adolescence. Here are some key points:

• Puberty is the period when individuals become capable of reproduction.
• In girls, puberty often starts earlier than in boys, usually around age 10 to 12.
• This phase lasts until they reach full reproductive maturity.

Understanding these changes is essential for recognising the development process during adolescence.

Stoppage of Menstruation: Menopause
Menopause is the correct answer choice for the stoppage of menstruation. Here's a detailed explanation:
Definition:
- Menopause refers to the natural biological process in women when they stop having menstrual periods permanently.
- It marks the end of the reproductive years and typically occurs between the ages of 45 and 55.
Key Points:
- Menarche: The term "menarche" refers to the onset of menstruation in girls, usually around the age of 12-14.
- Puberty: Puberty is a stage of development in which a person becomes capable of sexual reproduction. It involves various physical changes, including the onset of menstruation in girls.
- Adolescence: Adolescence is the transitional period between childhood and adulthood, typically characterized by puberty and the associated physical, emotional, and social changes.
Explanation:
- Menarche and puberty are related to the beginning of menstruation and the development of reproductive capabilities in girls.
- Menopause, on the other hand, refers to the cessation of menstruation, marking the end of a woman's reproductive years.
- During menopause, the ovaries stop releasing eggs and produce lower levels of hormones, leading to the absence of menstrual periods.
Conclusion:
- Menopause is the correct answer for the stoppage of menstruation.
- Menarche, puberty, and adolescence are all related to the onset and development of menstruation, but not the cessation of it.

The correct answer is C as the male hormone is Testosterone. This hormone is the primary sex hormone and an anabolic steroid in males. It plays a crucial role in:

• Development of male reproductive tissues.
• Growth of facial hair and deepening of the voice.
• Regulating other physical changes during puberty.

In summary, testosterone is essential for the physical and reproductive development in males.

False: The stomach is not called the voice box.
Explanation:
- The voice box is actually another term for the larynx, which is an organ located in the throat.
- The larynx plays a crucial role in producing sound and allowing us to speak.
- On the other hand, the stomach is part of the digestive system and is responsible for breaking down food and absorbing nutrients.
- While both the voice box and the stomach are important organs, they serve different functions in the body.
- It is important to use the correct terminology to avoid confusion and ensure clear communication in medical and anatomical contexts.

 

Chemicals secreted by endocrine glands are not called enzymes. The correct answer is False.

Explanation:

• Endocrine glands produce hormones, which are different from enzymes. Hormones are released into the bloodstream and act as messengers to regulate various bodily functions.
• Enzymes are proteins that act as catalysts in biochemical reactions, speeding up chemical processes in the body. They are not secreted by endocrine glands.
• Enzymes are produced by various organs, such as the pancreas, liver, and stomach.
• Endocrine glands include the pituitary gland, thyroid gland, and adrenal glands, each secreting specific hormones that regulate different functions.
• Hormones are crucial for maintaining homeostasis, growth, metabolism, reproduction, and other physiological processes.
• It is essential to differentiate between hormones and enzymes, as they serve different functions in the body.

Therefore, the statement that the chemicals secreted by endocrine glands are called enzymes is false.

Insulin is a hormone produced by the pancreas, not the pituitary gland. It plays a crucial role in regulating blood sugar levels.

The pancreas releases insulin through the following process:

• Insulin is produced by beta cells in the islets of Langerhans.
• It is released in response to food intake.

Therefore, the statement that insulin is produced by the pituitary gland is false.

Explanation:
Chromosomes in human cells:
- Chromosomes are thread-like structures located in the nucleus of a cell.
- They carry genetic information in the form of DNA.
- Humans have 23 pairs of chromosomes in total.
Number of chromosomes:
- Each pair of chromosomes consists of one chromosome from the mother and one from the father.
- So, in total, there are 46 individual chromosomes in a human cell (23 pairs).
Therefore, the statement that there are 23 pairs of chromosomes in the nuclei of human cells is true.

Explanation:

Diabetes:

• Diabetes is a chronic condition marked by high blood sugar levels.
• It arises when the body cannot effectively use or produce enough insulin, a hormone that controls blood sugar levels.

Insulin and Pancreas:

• Insulin is made by the pancreas, located in the abdomen.
• The pancreas releases insulin when blood sugar levels rise.
• Insulin helps move glucose from the blood into cells for energy.
• In diabetes, there is either not enough insulin produced or the body does not respond to it.

Types of Diabetes:

• Type 1 Diabetes:
  • The immune system attacks and destroys insulin-producing cells in the pancreas.
  • This leads to little or no insulin production.
  • Type 1 diabetes is often diagnosed in childhood or adolescence.
• Type 2 Diabetes:
  • This is the most common type of diabetes.
  • It occurs when the body becomes resistant to insulin or does not produce enough.
  • Factors like an unhealthy diet, lack of exercise, and obesity can lead to Type 2 diabetes.
  • It can develop at any age but is more common in adults.

Conclusion:

• Diabetes is indeed caused by insufficient insulin secretion or a lack of response to insulin.
• This can result from various factors, including autoimmune destruction of insulin-producing cells (Type 1) or insulin resistance (Type 2).
• Thus, the statement "Diabetes is caused by less secretion of insulin by the pancreas" is generally accurate but does not cover all aspects of diabetes.

Estrogen is a male hormone - False

• Estrogen is primarily a female hormone, though it is found in both males and females in varying amounts.

• It plays a key role in the development and regulation of the female reproductive system and secondary sexual characteristics.

• In males, the main hormone is testosterone, which regulates the male reproductive system and secondary sexual traits.

• Estrogen is crucial for the menstrual cycle, pregnancy, and the development of female characteristics like breast growth and hip widening.

• Additionally, it helps regulate bone density, cholesterol levels, and supports cardiovascular health.

• In males, estrogen is present in smaller quantities, mainly produced in the testes and adrenal glands.

• An imbalance in estrogen levels in males can lead to health issues such as gynecomastia (enlarged breasts), reduced libido, and infertility.

• Thus, it is incorrect to classify estrogen as a male hormone; it is primarily associated with females but is also present in males.

Puberty typically occurs in girls between the ages of 10 and 14. In contrast, boys generally experience puberty later, between 12 and 16.

The period of life when the body undergoes significant changes leading to reproductive maturity is known as adolescence. This phase usually begins around the age of 11 and can last until 18 or 19 years old.

• Adolescence is marked by various physical changes.
• These changes include growth spurts and the development of secondary sexual characteristics.
• For girls, this may involve breast development and the start of menstrual cycles.
• Boys may notice facial hair growth and a deeper voice.

It is important to note that the onset of puberty varies for each individual, and some may experience these changes earlier or later than their peers.

Explanation:

• Gametes, such as sperm and eggs, carry genetic information from parents to offspring.

• Sperm cells, produced by males, contain either an X or a Y chromosome.

• The X chromosome determines female traits, while the Y chromosome determines male traits.

• Thus, some sperm cells have an X chromosome, and others have a Y chromosome.

• If a sperm with an X chromosome fertilises an egg, the offspring will be female (XX).

• If a sperm with a Y chromosome fertilises an egg, the offspring will be male (XY).

• This process is how the biological sex of an individual is determined.

• The chance of fertilisation by either an X or Y sperm is approximately equal, resulting in about a 50% chance of having a male or female offspring.

• Out of the 23 pairs of chromosomes in humans, only one pair is called sex chromosomes.
• The 23rd pair determines sex: XX for females and XY for males.
•  The other 22 pairs are called autosomes.
• Therefore, the statement that two pairs are sex chromosomes is incorrect.

 So, the correct answer is B: False.