II. SHORT ANSWER TYPE QUESTIONS
1. How many chromosomes are there in a human cell? How do the chromosomes in males and females differ?
Answer:
A human cell has 46 chromosomes or 23 pairs.
Females have XX chromosomes, while males have XY chromosomes.
2. Name the gland which controls the secretion of hormones. Name some exocrine glands.
Answer:
The gland that controls the secretion of hormones is the pituitary gland.
Examples of exocrine glands are salivary glands, sweat glands, and tear glands.
3. Why do some adolescents get pimples on their face?
Answer:
Adolescents often get pimples because their oil glands become more active due to hormonal changes. These glands produce excess oil, which blocks skin pores and causes pimples.
4. Name the secondary sexual characteristics in humans.
Answer:
Secondary sexual characteristics include:
In boys: deeper voice, facial hair, body hair, broader shoulders.
In girls: development of breasts, widening of hips, body hair, and menstrual cycle.
5. What are hormones? Name the male and female hormones.
Answer:
Hormones are chemical messengers that control and coordinate activities in the body.
The main male hormone is testosterone.
The main female hormones are estrogen and progesterone.
6. What kind of food should be taken by adolescents?
Answer:
Adolescents should eat balanced meals that include proteins, carbohydrates, vitamins, minerals, milk, fruits, vegetables, and enough water. Junk food should be limited.
7. Why is protein very important for growing bodies?
Answer:
Protein is important because it helps in body growth, muscle building, and the repair of damaged tissues. Growing children need more protein for healthy development.
III. LONG ANSWER TYPE QUESTIONS
1. Name the male and female gametes. How does the reproductive phase in women differ from that in men?
Answer:
The male gamete is the sperm, and the female gamete is the ovum (egg).
The reproductive phase in women begins at puberty (around 10–14 years) and ends at menopause (around 45–50 years). Women release an egg every month and can conceive a baby.
In men, the reproductive phase starts at puberty (around 13–15 years) and usually continues throughout life. Men produce sperm continuously after puberty.
2. What is menstruation and menstrual cycle? What happens in the body of a female during menstrual cycle?
Answer:
Menstruation is the monthly shedding of the uterine lining in a woman’s body through the vagina.
The menstrual cycle is a 28-day cycle in which the ovary releases an egg. The uterus prepares a soft lining to receive a fertilized egg. If the egg is not fertilized, the lining breaks down and flows out as menstrual blood.
During the cycle:
- An egg matures in the ovary
- The uterus thickens
- If the egg is not fertilized, menstruation occurs
IV. HIGHER ORDER THINKING SKILLS
3. Describe the role of the following hormones: (a) estrogen (b) testosterone (c) insulin
Answer:
(a) Estrogen:
Controls development of breasts, menstrual cycle, and other female secondary characteristics.
(b) Testosterone:
Controls sperm production, deeper voice, facial hair, and other male secondary characteristics.
(c) Insulin:
Helps control blood sugar levels by allowing glucose to enter cells for energy.
4. How does an AIDS virus transmit from an infected person to a healthy person?
Answer:
AIDS spreads when the HIV virus enters the blood of a healthy person. It can spread through:
- Unprotected sexual contact
- Sharing infected needles
- Transfusion of infected blood
- From infected mother to baby during birth or breastfeeding
It does not spread through touching, hugging, or sharing food.
5. Why teenage pregnancy should be prevented?
Answer:
Teenage pregnancy should be prevented because:
- The girl’s body is not fully developed for childbirth
- Higher risk of health problems for mother and baby
- Education and career get affected
- Emotional stress increases
6. In the given figure, name X, Y and Z. Also mention their functions.
Answer:
- Z – Pituitary gland
Function: Controls growth and regulates other glands. - X – Thyroid gland
Function: Produces thyroxine, which regulates metabolism. - Y – Adrenal gland
Function: Produces adrenaline, which prepares the body for stress.
1. Vishal has a very big and bulging throat. Name:
(a) the disease Vishal is suffering from?
(b) the gland associated with the disease.
(c) the hormone whose deficiency caused the disease.
Answer:
(a) Vishal is suffering from goitre.
(b) The affected gland is the thyroid gland.
(c) The deficiency of thyroxine hormone causes this disease.
2. A gland ‘A’ attached to brain secretes hormones that stimulate testes and ovaries to produce their hormones ‘B’ and ‘C’ respectively.
(a) Name the gland ‘A’. What kind of gland is it?
(b) Name the hormones ‘B’ and ‘C’ and mention their function.
Answer:
(a) The gland ‘A’ is the pituitary gland. It is an endocrine gland.
(b)
- Hormone B (from testes): Testosterone
Function: Controls sperm production and male secondary sexual characteristics. - Hormone C (from ovaries): Estrogen
Function: Controls the menstrual cycle and female secondary sexual characteristics.