Reaching the Age of Adolescence Class 8 Science Extra Questions and Answers
Reaching the Age of Adolescence Class 8 Science Chapter 10 Extra Questions and Answers are provided here. We prepared these extra questions based on the latest NCERT Class 8 Science Book. CBSE Class 8 Science Chapter 10 Reaching the Age of Adolescence Extra Questions will help you to properly understand a particular concept of the chapter.
Class 8 Science Chapter 10 Reaching the Age of Adolescence Extra Questions
Very Short Answer Type Question
Question 1: Name the hormone that regulates secondary sexual characters in males.
Answer: Testosterone
Question 2: Name the hormone that regulates secondary sexual characters in females.
Answer: Estrogen
Question 3: Which virus causes AIDS?
Answer: AIDS is caused by a dangerous virus, HIV.
Question 4: Which of the two, sperm or egg cell (ovum), decides the sex of the child?
Answer: Sperm decides the sex of the child.
Question 5: What is goitre?
Answer: A goiter is an abnormal enlargement of thyroid gland.
Question 6: Which hormone deficiency in the body causes diabetes?
Answer: Deficiency of insulin hormone in the body causes diabetes.
Question 7: How do shoulders and chest change in boys during puberty?
Answer: Boys develop broader shoulders and wider chests during puberty.
Question 8: What is the other name of voice box?
Answer: The larynx is another name for the voice box.
Question 9: Name some endocrine glands.
Answer: Pituitary, Testes, Ovaries, Thyroid, Pancreas and Adrenals
Question 10: What is the natural balanced food for infants?
Answer: For infants, mother’s milk provides all the nourishment that they need.
Question 11: Name the female sex hormone.
Answer: Estrogen is the female sex hormone released by ovaries.
Question 12: Name the male sex hormone.
Answer: Testosterone is the male sex hormone released by the testes.
Question 13: What gland controls sex hormones?
Answer: Pituitary gland controls sex hormones.
Question 14: Name the endocrine gland attached to the brain.
Answer: Pituitary gland is an endocrine gland attached to the brain.
Question 15: Which endocrine gland secretes growth hormone?
Answer: Pituitary gland secretes growth hormone.
Question 16: What element is needed for thyroxine production?
Answer: Thyroxine production requires the presence of iodine.
Question 17: State the main symptom of goitre.
Answer: Main symptom of goitre include very big and bulging throat.
Question :18 Which hormone deficiency in the body causes goitre?
Answer: Goitre is caused by deficiency of thyroxine hormone in the body.
Question 19: Which gland secretes insulin hormone?
Answer: Pancreas secretes insulin hormone.
Question 20: Who attains puberty at an earlier age in human beings: boys or girls?
Answer: In girls, adolescence may begin a year or two earlier than in boys.
Question 21: What is the most conspicuous change during puberty?
Answer: The most conspicuous change during puberty is the sudden increase in height.
Question 22: State the age at which adolescence usually begins and the age up to which it lasts.
Or
At what age adolescence usually begins and up to which it lasts?
Answer: Adolescence begins around the age of 11 and lasts up to 18 or 19 years of age.
Question 23: Which disease is caused by the insufficient production of insulin hormone by pancreas?
Answer: Diabetes is caused by the insufficient production of insulin hormone by pancreas.
Question 24: Which endocrine gland secretes hormone that maintains correct salt balance in the blood?
Answer: Adrenal glands secrete hormones which maintain the correct salt balance in the blood.
Short Answer Type Questions
Question 1: What is the legal age for marriage of boys and girls in our country?
Answer: In our country, the legal age for marriage is 18 years for girls and 21 years for boys.
Question 2: How do hips of girls change during puberty?
Answer: Girls develop broader hips during puberty. Due to this, region below the waist becomes wider.
Question 3: Why endocrine glands are called ductless glands?
Answer: Endocrine glands release hormones directly into the bloodstream. So, they are also termed ductless glands.
Question 4: Which hormone is responsible for metamorphosis in frog?
Answer: In a frog, metamorphosis is controlled by thyroxine, the hormone produced by thyroid.
Question 5: Which two male sex organs develop completely at puberty?
Answer: At puberty, male sex organs like the testes and penis develop completely. The testes also begin to produce sperms.
Question 6: Which two female sex organs develop completely at puberty?
Answer: In girls, the ovaries enlarge and eggs begin to mature. Also ovaries start releasing mature eggs.
Question 7: What is puberty?
Answer: The period during which adolescent boys and girls reach sexual maturity and become capable of reproduction is called puberty.
Question 8: What are hormones? Where are hormones made in the human body?
Answer: Hormones are chemical substances. These are secretions from endocrine glands, or endocrine system.
Question 9: What is the function of adrenalin hormone in the body?
Answer: Adrenals also produce the hormone adrenalin. It helps the body to adjust to stress when one is very angry, embarrassed or worried.
Question 10: Name the time period in one’s life when the brain has the greatest capacity for learning.
Answer: Adolescence is often the time in one’s life when the brain has the greatest capacity for learning.
Question 11: Why is exercise important during adolescence?
Answer: Walking and playing in fresh air keeps the body fit and healthy. Thus, all young boys and girls should take walks, exercise and play outdoor games.
Question 12: What is the effect of a smaller voice box in grown up girls?
Answer: In girls, the larynx is hardly visible from the outside because of its small size. The smaller voice box in girls gives shrill voice or high pitched voice to the girls.
Question 13: Why is iron mineral important for our body? Write some iron rich foods.
Answer: Iron mineral is important for our body because it builds blood. Iron-rich food includes leafy vegetables, jaggery, meat, citrus, Indian gooseberry (amla) etc.
Question 14: When adolescent girls should take special care of personal hygiene?
Answer: Girls should take special care of cleanliness during the time of menstrual flow. They should keep track of their menstrual cycle and be prepared for the onset of menstruation.
Question 15: Why drugs should be avoided?
Answer: Drugs should be avoided because they are addictive. If we take them once, we
feel like taking them again and again. They harm the body in the long run. They ruin health and happiness.
Question 16: What is the effect of a larger voice box in grown up boys?
Answer: The bigger voice box in boys gives deeper voice or low pitched voice to the boys. In adolescent boys, sometimes, the muscles of the growing voice box go out of control and the voice becomes hoarse.
Question 17: What is menarche and menopause?
Answer: Menstruation occurs once in about 28 to 30 days. The first menstrual flow begins at puberty and is termed menarche. At 45 to 50 years of age, the menstrual cycle stops. Stoppage of menstruation is termed menopause.
Question 18: Why do young people get acne?
Answer: During puberty the secretion of sweat glands and sebaceous glands (oil glands) increases. Many young people get acne and pimples on the face at this time because of the increased activity of these glands in the skin.
Question 19: What is the term used for secretions of endocrine glands responsible for changes taking place in the body?
Answer: Hormones are chemical substances. These are secretions from endocrine glands, or endocrine system. They are responsible for changes taking place in the body.
Question 20: Why is good hygiene important during adolescence?
Or
Why is it necessary for adolescents to take bath regularly?
Or
What will happen if personal hygiene is not maintained by adolescent?
Answer: It is necessary for teenagers because the increased activity of sweat glands sometimes makes the body smelly. All parts of the body should be washed and cleaned every day. If cleanliness is not maintained there are chances of catching bacterial infection.
Question 21: Why early marriage and motherhood is harmful to the girls?
Answer: Early marriage and motherhood cause health problems in the mother and the child. It also curtails employment opportunities for the young woman and may cause mental agony as she is not ready for responsibilities of motherhood.
Question 22: What will happen if the water in which tadpoles are growing does not contain iodine?
Answer: In a frog, metamorphosis is controlled by thyroxine, the hormone produced by thyroid. Thyroxine production requires the presence of iodine in water. If the water in which the tadpoles are growing does not contain sufficient iodine, the tadpoles cannot become adults.
Long Answer Type Questions
Question 1: Define adolescence.
Answer: The period of life, when the body undergoes changes, leading to reproductive maturity, is called adolescence. Adolescence begins around the age of 11 and lasts upto 18 or 19 years of age. In girls, adolescence may begin a year or two earlier than in boys. Also, the period of adolescence varies from person to person.
Question 2: How AIDS spread?
Or
What are the various ways in which AIDS virus HIV can be transmitted?
Or
Explain how the use of drugs helps in spreading AIDS disease.
Answer: AIDS which is caused by a dangerous virus, HIV. This virus can pass on to a normal person from an infected person by sharing the syringes used for injecting drugs. It can also be transmitted to an infant from the infected mother through her milk. The virus can also be transmitted through sexual contact with a person infected with HIV.
Question 3: On what factors height depends?
Or
What determines the height of a person?
Answer: Height of an individual is more or less similar to that of some family member. This is because height depends on the genes inherited from parents. It is, however, very important to eat the right kind of food during these growing years. This helps the bones, muscles and other parts of the body get adequate nourishment for growth.
Question 4: How does the height of boys and girls change during puberty?
Answer: At the time of puberty the long bones, that is, the bones of the arms and the legs elongate and make a person tall. Initially, girls grow faster than boys but by about 18 years of age, both reach their maximum height. The rate of growth in height varies in different individuals. Some may grow suddenly at puberty and then slow down, while others may grow gradually.
Question 5: Prepare a Table having two columns depicting names of endocrine glands and hormones secreted by them.
Answer:
| Endocrine glands | Hormones |
| Thyroid gland | thyroxine |
| Pancreas | insulin |
| Pituitary | growth hormone |
| Adrenals | adrenalin |
| Testes | testosterone |
| Ovaries | estrogen |
Question 6: What is menstruation? Explain.
Answer: In females, the reproductive phase of life begins at puberty (10 to 12 years of age) and generally lasts till the age of approximately 45 to 50 years. The ova begin to mature with the onset of puberty. One ovum matures and is released by one of the ovaries once in about 28 to 30 days. During this period, the wall of the uterus becomes thick so as to receive the egg, in case it is fertilised and begins to develop. This results in pregnancy. If fertilisation does not occur, the released egg, and the thickened lining of the uterus along with its blood vessels are shed off. This causes bleeding in women which is called menstruation.
Question 7: What are sex hormones? Why are they named so? State their function.
Answer: Sex hormones are chemical substances produced by a sex gland or other organ. For example, the testes make male sex hormone called testosterone and the ovaries make female sex hormone called estrogen. These hormones affect the sexual features of an organism. Hence they are called sex hormones.
Functions
Testosterone – It produces male secondary sexual characteristics in boys such as deeper voice, growth of moustache and beard, broad shoulders and chest, adam’s apple, more muscles, development of reproductive organs etc.
Estrogen – It produces female secondary sexual characteristics in girls such as development of breasts, broader hips, development of reproductive organs etc.
Question 8: List changes in the body that take place at puberty.
Or
State some of the changes which take place in boys and girls during adolescence.
Answer: Changes at puberty
- Sudden increase in height and weight.
- Boys develop broader shoulders and wider chests. In girls, the region below the waist becomes wider.
- In boys, the muscles of the body grow more prominently than in the girls.
- Boys develop larger voice boxes. The growing voice box in boys can be seen as a protruding part of the throat called Adam’s apple.
- Development of pimples and acne on the face due to the increased activity of sebaceous glands and sweat glands present in the skin.
- At puberty, male sex organs like the testes and penis develop completely. The testes also begin to produce sperms. In girls, the ovaries enlarge and eggs begin to mature.
- In girls, breasts begin to develop at puberty and boys begin to grow facial hair, that is, moustaches and beard.
- Boys also develop hair on their chest. In both, boys and girls, hair grows under the arms and in the region above the thighs or the pubic region.
Question 9: Write notes on—
(a) Adam’s apple.
(b) Secondary sexual characters.
(c) Sex determination in the unborn baby.
Answer: (a) Adam’s apple – At puberty, the voice box or the larynx begins to grow. Boys develop larger voice boxes. The growing voice box in boys can be seen as a protruding part of the throat called Adam’s apple.
(b) Secondary sexual characters – In girls, breasts begin to develop at puberty and boys begin to grow facial hair, that is, moustaches and beard. As these features help to distinguish the male from the female they are called secondary sexual characters. Boys also develop hair on their chest. In both, boys and girls, hair grows under the arms and in the region above the thighs or the pubic region.
(c) Sex determination in the unborn baby – All human beings have 23 pairs of chromosomes in the nuclei of their cells. Two chromosomes out of these are the sex chromosomes, named X and Y. A female has two X chromosomes, while a male has one X and one Y chromosome. The gametes (egg and sperm) have only one set of chromosomes. The unfertilised egg always has one X chromosome. But sperms are of two kinds. One kind has an X chromosome, and the other kind has a Y chromosome. When a sperm containing X chromosome fertilises the egg, the zygote would have two X chromosomes and develop into a female child. If the sperm contributes a Y chromosome to the egg (ovum) at fertilisation, the zygote would develop into a male child.
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