In this page, we are providing Reaching the Age of Adolescence Class 8 Extra Questions and Answers Science Chapter 10 pdf download. NCERT Extra Questions for Class 8 Science Chapter 10 Reaching the Age of Adolescence will help to score more marks in your CBSE Board Exams.
Class 8 Science Chapter 10 Extra Questions and Answers Reaching the Age of Adolescence
Extra Questions for Class 8 Science Chapter 10 Reaching the Age of Adolescence with Answers Solutions
Reaching the Age of Adolescence Class 8 Extra Questions Very Short Answer Type
Question 1.
What is Adam’s apple?
Answer:
The protruding part of the throat in males is called Adam’s apple.
Question 2.
Name the hormone in female that is produced by ovaries and helps in development of mammary glands.
Answer:
Estrogen
Question 3.
Whose height grow faster initially boys or girls?
Answer:
Girls
Question 4.
Name a gland which transports secretions through ducts.
Answer:
Sweat glands/salivary glands/ oil gland (any one).
Question 5.
What is puberty?
Answer:
The age at which boys and girls become capable of reproduction.
Question 6.
What are hormones?
Answer:
The chemical substances produced by endocrine glands are called hormones.
Question 7.
How long is a woman’s reproductive life lasts?
Answer:
Menarche to menopause.
Question 8.
Name the female hormone.
Answer:
Estrogen
Question 9.
Which gland is called master gland?
Answer:
Pituitary gland
Question 10.
What is a balanced diet?
Answer:
The meal that includes all nutrients is called a balanced diet.
Question 11.
What is menstruation?
Answer:
Extrusion of uterus lining and blood along with the unfertilised egg from the vagina is called menstruation.
Question 12.
What is menarche?
Answer:
The first menstrual flow begins at puberty and is termed as menarche.
Question 13.
What is menopause?
Answer:
Stoppage of menstruation is called menopause.
Question 14.
What causes goitre?
Answer:
Deficiency of thyroxine hormone.
Question 15.
Which gland secretes thyroxine?
Answer:
Thyroid gland
Question 16.
What are chromosomes?
Answer:
The thread-like structures in the nucleus are called chromosomes.
Question 17.
How many chromosomes are present in human cell?
Answer:
23 pairs or 46 chromosomes.
Question 18.
How many sex chromosomes are there in human cell?
Answer:
Two, i.e., one pair.
Question 19.
Which hormone is necessary for normal growth of a person?
Answer:
Growth hormone.
Question 20.
Which gland secretes insulin?
Answer:
Pancreas
Question 21.
What causes diabetes?
Answer:
Deficiency of insulin.
Question 22.
Name the chromosome present in a female.
Answer:
X chromosome
Question 23.
Name the chromosome present in a male.
Answer:
X and Y chromosomes
Question 24.
Which chromosome does the unfertilised egg contain?
Answer:
X chromosome
Question 25.
Which hormone balances the proportion of salts in the blood?
Answer:
Adrenaline
Question 26.
What decides the sex of an unborn child?
Answer:
Sex chromosome of father.
Question 27.
Name the glands other than the pituitary gland.
Answer:
Thyroid, pancreas and adrenals.
Question 28.
When does the puberty ends?
Answer:
Puberty ends when an adolescent reaches reproductive maturity.
Question 29.
Do the boys and girls undergo same physical changes at puberty?
Answer:
No
Question 30.
Why do we need to have a balanced diet?
Answer:
To keep the body healthy.
Reaching the Age of Adolescence Class 8 Extra Questions Short Answer Type
Question 1.
What is meant by adolescence?
Answer:
Growing up is a natural process. The period of life, when the body undergoes several changes leading to reproductive maturity, is cabled adolescence. The adolescence period is 11 to 19 years of age.
Question 2.
What is puberty?
Answer:
The period during which adolescent boys and girls attain sexual maturity and become capable of reproduction is called puberty. Puberty age of female is 10 to 12 years while male puberty age is 12 to 14 years.
Question 3.
What is vital change which marks puberty in boys and girls?
Answer:
During puberty, the human body undergoes several changes, but the most important changes which marks puberty is that boys and girls become capable of reproduction.
Question 4.
Why do boys have a hoarse voice at puberty?
Answer:
The voice box or larynx begins to grow at the onset of puberty. This growing voice box in boys can be seen as a protruding part of the throat called Adam’s apple. This leads to voice becoming hoarse.
Question 5.
How does the body shape change at puberty?
Answer:
Body shape changes differently in boys and girls at puberty. Boys have broader shoulders and wider chests. Their muscles grow more prominently than girls. In girls, the region below the waist becomes wider.
Question 6.
Why is adolescence also called teenage?
Answer:
Adolescence period is generally 11 to 19 years of age. Because the period covers the teens, i.e., 13 to 19 years of age, adolescents are also called teenagers.
Question 7.
Why do many young people have acne and pimples during adolescence?
Answer:
During puberty the secretion of sweat glands and sebaceous glands (oil glands) increases. It develops acne and pimples on the face of young boys and girls.
Question 8.
Why are endocrine glands also called ductless glands?
Answer:
Endocrine glands release hormones directly into the blood stream. So, they are termed as ductless glands. For example, pituitary, thyroid, pancreas, etc.
Question 9.
What are secondary sexual characters?
Answer:
At puberty, in girls, breasts begin to develop, the region below the waist become wider, voice become shriller. Boys begin to grow facial hair, i.e., moustache and beard. Boys also develop hair on their chest, the muscles of the body grow more prominently, develop larger voice box which can be seen as a protruding part of the throat called Adam’s apple. In both boys and girls, hair grows under the arms and in the pubic region. As these features distinguish the male from the female they are called secondary sexual characters.
Question 10.
Explain the development of sex organs in male and female.
Answer:
The male and the female sex organs develop completely at puberty. Male sex organ like testes and penis develop completely. The testes begin to produce the male gametes or sperm. Similarly in girls the ovaries enlarge and egg begins to mature. Ovaries start releasing matured eggs or ovum.
Question 11.
Why do changes occur in human body at puberty?
Answer:
The changes in human body at puberty occur due to release of hormones by different types of glands. Hormones are chemical substances secreted from endocrine glands or endocrine system. Male hormone or testosterone are responsible for changes in male whereas female hormone or estrogen are responsible for changes in female.
Question 12.
What is a pituitary gland?
Answer:
Different types of hormones are secreted by different types of glands. The product of all these hormones is under the control of another hormone secreted from an endocrine gland called pituitary gland.
Question 13.
How do hormones work in human body?
Answer:
Endocrine glands release hormones into the blood stream to reach a particular body part called target site. The target responds to the hormone. There are many endocrine glands or ductless glands in the body.
Question 14.
What are sex hormones? How do they work in the human body?
Answer:
Sex hormones help boys and girls develop sex organs to enable them for reproduction. These hormones lead them to reproductive maturity.
In girls, estrogen makes the breasts develop. Milk secreting glands or mammary glands develop inside the breasts. Ovaries begin to produce eggs. In boys, testosterone is released by testes. Testes begin to release sperms. Changes in boys is also seen due to this hormone.
Question 15.
What is menstruation?
Answer:
At puberty, in girls the ovaries get enlarged and start producing eggs (ovum). One egg 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. If the egg is fertilised then it begins to develop and results in pregnancy. If this egg is not fertilised, the released egg and thickened lining of the uterus along with its blood vessels are shed off causing bleeding in female which is called menstruation. It occurs once in about 28 to 30 days.
Question 16.
What are the changes in female at the onset of puberty?
Answer:
There are several changes in females at the onset of puberty. They are:
- growth of hair in armpit and pubic region.
- development of breasts and mammary glands.
- ovaries get enlarged and begin producing eggs.
- menstruation cycle starts; and
- increased activity of sweat and sebaceous glands.
Question 17.
Explain the terms menarche and menopause.
Answer:
The first menstrual flow begins at puberty and is termed as menarche.
At 45 to 50 years of age, the menstrual cycle stops. Stoppage of menstruation is called menopause.
Question 18.
What happens when the egg is fertilised?
Answer:
When the egg is fertilised, it begins to divide and then gets embedded in the uterus for further development. Finally the fertilised egg develops into a foetus.
Question 19.
What are the changes in males at puberty?
Answer:
There are various changes in males at puberty.
They are:
- sudden increase in height.
- growth of hair at different parts of body like face, armpit and pubic region, development of moustache and beard.
- development of Adam’s apple in throat, voice becomes hoarse.
- shoulders become broader and chest wider.
- growth of size of reproductive organs like penis, testes begin to produce sperms, etc.
Question 20.
What do you mean by reproductive health?
Answer:
The physical and mental well being of an individual is regarded as an individual’s health. To keep the body healthy, every human being, at any age, needs to have a balanced diet. The person must also observe personal hygiene and undertake adequate physical exercise. Thus, reproductive health refers to the diseases, disorders and conditions that affect the functioning of the male and female reproductive system during all stages of life.
Question 21.
What is the role of hormones in completing the life history of insects and frogs?
Answer:
Hormones play an important role in the completion of life cycle of insects and frogs. Metamorphosis in insects is controlled by insect hormones. In a frog, it is controlled by thyroxine, the hormone produced by thyroid gland. Thyroxine production requires the presence of iodine in water. Water in which iodine is not, present, the tadpoles cannot become adult.
Question 22.
Which hormone is released by pancreas? What is its function?
Answer:
Insulin is released by pancreatic gland. It regulates sugar metabolism. If insulin is deficient in the body, sugar level becomes high in blood causing diabetes.
Reaching the Age of Adolescence Class 8 Extra Questions Long Answer Type
Question 1.
What changes occur in human at puberty?
Answer:
There are various changes in human at puberty. They are as follows:
(i) Change in height: During puberty, there is sudden increase in height in boys and girls. Initially, girls grow faster in height than in boys. But both reach their maximum height at the age of 18 years.
(ii) Change in voice: Boys develop larger voice box or larynx to form protruding part of throat called Adam’s apple making their voice hoarse, girls have high pitched voice.
(iii) Change in body shape: In boys, shoulders broaden and muscles grow more prominently than in girls. In girls the region below the waist becomes wider.
(iv) Secretion of sweat and sebaceous glands (oil glands) in both boys and girls increases and acne or pimples grow on faces of many youths.
(v) Development of sex organs: In males, testes and penis develop completely. Testes begin producing sperms. In girls, ovaries are enlarged and begin to produce eggs. Both boys and girls reach reproductive maturity.
(vi) In girls, menstruation or periods starts.
(vii) All human beings attain mental, intellectual and emotional maturity at puberty.
(viii) Facial hair like moustache and beard are grown in boys. Hair are grown in armpit and pubic region in both boys
and girls. Breasts are developed in girls. These characters are called secondary sexual characters as they distinguish a male from a female.
Question 2.
Explain the reproductive phase of life in humans.
Answer:
Boys and girls become capable of reproduction at puberty because their testes and ovaries begin to release gametes, i.e., sperms and ova respectively. In girls, reproductive phase of life begins at puberty from 10 to 12 years of age and generally lasts till the age of 45 to 50 years. The ova begin to mature with the onset of puberty. The ovum matures and is released by one of the ovaries once in 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 menstruation. It occurs once in about 28 to 30 days. The first menstrual flow begin at puberty and is termed as menarche. The menstruation stops at the age of 45 to 50. This stage is known as menopause. In male, the reproductive phase begins at puberty at the ages 14-15 and lasts as long as he is healthy.
Question 3.
Mention different types of glands, their functions and hormones secreted by them.
Answer:
There are different types of glands in our body and they secrete different types of hormones which control grotto, behaviour, development and reproduction. The following table shows different types of glands, hormones secreted by them and their functions:
| S. No. | Name of glands | Hormones secreted | Functions |
| 1. | Pituitary | Several hormones including growth hormone, thyroid stimulating hormones, etc. | (i) Produces thyroxine hormone and stimulate thyroid gland. (ii) Controls growth. (iii) Keeps a check on the activity of other glands. |
| 2. | drenal | Adrenaline | (i) Regulates blood pressure, breathing rate, heart beat, etc. (ii) Helps the body to adjust the stress condition. |
| 3. | Thyroid | Thyroxine | (i) Helps in controlling growth, respiration and metabolism. (ii) Prevents from goitre disease. |
| 4. | Testes | Male hormone or testosterone | Develops secondary sexual characters and control releasing of sperms. |
| 5. | Ovaries | Female hormone or estrogen | Develop secondary sexual character, maturation and release of ovum and helps in maintaining the growth of uterus during pregnancy. |
| 6. | Pancreas | Insulin | Controls sugar level and prevents from diabetes. |
Question 4.
Explain sex determination in human.
Answer:
Sex determination of a baby is done at the time of fertilisation when a male gametes fuse with a female gamete. It depends on male partner whether the baby will be a male child or female child. The chances of child to be male or female actually depend on the chromsomes present in the fertilised eggs or ova. There are 23 pairs of chromosomes in the nuclei of all human beings out of which two are sex chromosomes named X and Y.
A male has one X and one Y chromosome and a female has two X chromosomes. The gametes (egg and sperm) have only one set of chromosomes. The unfetilised 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. Fig. 10.5 shows sex determination in humans.
Question 5.
Explain the term reproductive health. What should we do to maintain reproductive health?
Answer:
The state of physical, mental and social well being of an individual is regarded as an individual’s health. A healthy person is free from disease, tension and anxiety. Reproductive health refers to a state of physical, mental and social well-being in all matters relating to the reproductive system, at all stages of life.
We should take following measures to maintain reproductive health:
- To have a balanced diet: As far as practicable, we should have a balanced diet, i.e., a diet containing proteins, vitamins, carbohydrates, fats and minerals. We can have our food which contain these nutrients.
- To take physical exercise: We should take physical exercise like morning walk, running, etc., daily.
- To maintain personal hygiene: We should maintain personal hygiene to stay fit and healthy. We should wash our body especially pubic region, armpit, etc., properly.
- Avoid harmful drugs: We should avoid taking harmful drugs and alcohol.
Reaching the Age of Adolescence Class 8 Extra Questions HOTS
Question 1.
One day Seema’s uncle visited her place. Seema prepared dinner for him. When she was about to put rock salt on the salad, her uncle interrupted her and asked to put iodised salt instead of rock salt. He also advised her to prefer iodised salt instead of rock salt. Why do you think Seema’s uncle advised her to have iodised salt instead of rock salt?
Answer:
Deficiency of iodine causes goitre disease in our body. This is why Seema’s uncle advised her to have iodised salt.
Question 2.
It is said that height of a child depends upon the genes inherited from the parents. Are there factors other than genes that causes variation in height?
Answer:
Other factors like nutrition, release of growth hormones, exercises, diseases, etc., also have impact on the height of a growing child.
Question 3.
Is a woman responsible for the birth of a girl child? Explain.
Answer:
No, because a woman has eggs of only X chromosomes but a male has sperms of both X and Y chromosomes. It is the type of male chromosome (X or Y) which fuses with the egg and determine the sex of the foetus, i.e., whether it will be male (XY) or female (XX) child.
Question 4.
John and Radha were classmates since childhood. When Radha became eleven years old, she developed a little swelling on her neck. She visited the doctor who started medication for her. After a few years, John also developed a slight protrusion on his throat. He got worried and went to the doctor. But, the doctor assured him that it was a normal feature in boys while they are growing up. Can you think of any reasons for the difference in diagnoses?
Answer:
The swelling on the neck of Radha may be because of insufficient production of thyroxine which results in goitre. However slight protrusion in John’s throat may be due to enlargement of voice box, also known as Adam’s apple, in adolescent boys.
Question 5.
Why we should not take medicines or drugs unless prescribed by a doctor?
Answer:
Certain medicines have specific dosage levels and adverse side effects which if not followed may be proved lethal to us. Drugs can be addictive too and can ruin our health and happiness.
Reaching the Age of Adolescence Class 8 Extra Questions Value Based (VBQs)
Question 1.
Salma had a very soft and smooth skin during her childhood. As she entered adolescence, she developed pimples on her face, her body became taller compared to her face. She got worried of all of the sudden changes. Her mother explained that all these changes are normal and advised her to wash her face at regular intervals.
(a) Why Salma’s mother advised Salma to wash her face at regular intervals?
(b) What is the reason for appearance of pimples on her face?
(c) Why Salma experienced disproportionate growth of the body?
(d) What values do we get from this?
Answer:
(a) Regular face wash keeps the face clean and dry and helps to reduce the pimples.
(b) During adolescence, secretion of sweat glands and sebaceous glands increases leading to formation of acne and pimples.
(c) During adolescence, all parts of the body do not grow at the same rate. Sometimes the arms and legs or hands and feet of adolescents look oversized and out of proportion with the body.
(d) We must be self-aware, must take proper care and diet during the growing period, not get worried or lose our self-esteem.