Reaching the age of adolescence

Q1) what is puberty?

Ans: the process of physical changes by which an individual becomes capable of reproduction is called puberty.

Q2) which is the male sex hormone?

Ans: testosterone

Q3) which female organ produces estrogen and progesterone hormone

Ans: ovaries

Q4) which male organ produces testosterone

Ans: testes

Q5) what is the normal duration of menstrual cycle?

Ans: 28 to 30 days.

Q6) what is menopause?

Ans: at about 50 years of age, the menstrual cycle stops. This is known as menopause.

Q7) During which phase of the menstrual cycle is a mature egg released by one of the ovaries?

Ans: During the mid-cycle normally one mature egg cell is released by the ovary.

Q8) which pair of chromosomes determines the sex of a male and a female child?

Ans: sex chromosomes.

Q9) why do acne and pimples erupt on the skin during puberty?

Ans: during puberty, there is an increase in the activity of sweat and oil glands. The skin becomes oily and acne and pimples may erupt on the skin.

Q10) Differentiate between exocrine and endocrine glands?

Ans: Exocrine glands: the glands that releases its secretions with the help of a duct at a specific place is called an exocrine glands.

For example, the salivary glands secrete saliva in the mouth with the help of salivary duct.

Endocrine glands: the human body has several endocrine glands. They are pituitary glands, hypothalamus, thyroid

Gland, parathyroid gland, adrenal gland, pineal gland and reproductive glands.

The testes in the male and ovaries in the female form the reproductive endocrine glands.

Q11) Explain with an example why the pituitary glands is called the master gland?

Ans: the pituitary gland is called the master gland as its hormones control the activities of many other endocrine glands.

For example, the pancreas and adrenal glands are simulated by the pituitary gland to create insulin and adrenaline respectively.

Q12) why do tadpoles that grow in water deficient in iodine fail to develop into adult frog?

Ans: in frogs, metamorphosis is controlled by thyroxine produced by the thyroid gland, iodine is required for the proper production of thyroxine. This is why tadpoles that grow in water that id deficient in iodine fail to develop into adult frog.

Q13) list two ways by which young people may refrain from indulging in undesirable activities?

Ans: play outdoor games, develop hobbies such as painting, singing, photography, gardening or playing music. Awareness of the addictive nature of bad habits and their consequences will also help one to stay out of such activities.

Q14) write a short note on puberty in boys and girls.

Ans: in girls, during puberty, the hormones estrogen and progesterone develop female sexual features. The breasts begin to develop and the body becomes more rounded, especially the hips. The growth of the body accelerates and girls begins menstruating.

During puberty in boys, hormones from the pituitary gland and testosterone bring about the physical changes that make a boy mature into an adult male.

Q15) Explain the menstruation cycle in girls.

Ans: once a girl is an adolescent, menstruation occurs regularly once in about 28 to 30 days. This regular physiological process is called menstrual cycle. Menstruation begins at puberty. The first menstruation is termed menarche. In the beginning cycle may be irregular. After sometime it becomes regular. The menstrual cycle is controlled by certain hormones. During the mid-cycle normally one mature egg cell is released by the ovary. If the egg gets fertilized, it gets embedded in the uterus and begins to develop.

During each menstrual cycle, the wall of the uterus prepares to receive a fertilized egg. The uterine wall thickens and is richly supplied by additional blood vessels.

Q16) what is the importance of diet during adolescence?

Ans: a balanced diet of an adolescent should include the required amounts of carbohydrates, proteins, fats, vitamins and minerals to meet the needs of rapidly developing body. Food items like pulses, mushrooms, milk, eggs, fish and meat are rich in proteins.

Q17) How is the gender of a child determined ?

Ans: being a male or a female is dependent on the particular pair of chromosomes.

This pair is known as sex chromosomes. There are two  types of sex chromosomes “ x” and “ y “. Every cell of a male has one “x” and one “ y”, whereas the pair of sex chromosomes in a female has two “ x “ chromosomes. During fertilization, as sperm having “x” chromosomes or a “ y “ chromosomes fuses with an egg. The fertilized egg will have “x x “chromosomes. This zygote with “xx” chromosome will develop into a baby girl. If a sperm having “y” chromosomes, fuses with an egg “ x” then the fertilized egg has “x y “ chromosomes. This zygote with “x y “ sex chromosomes will develop into a baby boy.