CBSE Class 8 Science Reaching The Age Of Adolescence Worksheet

Question. What is the most important reason we SWEAT?
(a) to eliminate excess water from our body
(b) to reduce excess body weight
(c) to cool down our body
(d) to eliminate wastes from our body

Answer : C

Question. When Saurabh saw a thief entering his house stealthily in the middle of night, he was alarmed and his heart started beating fast. These symptoms could be attributed to the action of which hormone?
(a) Adrenaline
(b) Thyroxin
(c) Testosterone
(d) Insulin

Answer : A

Question. Study this bar graph showing the energy content per gram of some foods. Which of the following items in Sudha’s food would give her maximum energy?

(a) 3 chapattis (120 gm)
(b) 1 cup green gram dal (100 gm)
(c) 2 boiled eggs (80 gm)
(d) 1 banana (100 gm)

Answer : B

Question. Marathon runners need to stay trim and healthy but also need a lot of energy - which of these foods would be most suitable for a marathon runner?

(a) A
(b) B
(c) C
(d) D

Answer : A

Question. The US Food and Drug Administration allows certain claims to be made when foods satisfy related conditions. Here are some of those claims: "Fat free": Less than 0.5 gram of fat per serving.
"Low fat": 3 grams or less per serving.
"Cholesterol free": Less than 2 mg of cholesterol per serving.
"Low cholesterol": 20 mg or less of cholesterol per serving.
"Saturated Fat Free": Less than 0.5 gram of saturated fat per serving.
"Low Saturated Fat": 1 gram or less per serving or not more than 15 percent of calories from saturated fat.
"Sodium free": Less than 5 mg of sodium per serving.
"Low sodium": 140 mg or less per serving.
For a serving of 2 slices for which the information is shown, which of these claims can be made?"
Answer the question based on the information below:
Our bodies need energy to live and grow, and this is provided by the food we eat. The energy provided by different nutrients like carbohydrates, fats and proteins is shown in this table: (Other components do not contribute significantly to the total calories.) 

(a) Fat Free and Saturated Fat Free
(b) Low Fat
(c) Low Sodium
(d) (None of these claims can be made)

Answer : D

Question. In 1747 as the HMS Salisbury sailed from England to the Plymouth Colony, the ship's physician, James Lind, performed a simple experiment to determine what might be effective as a cure for scurvy. On May 20, 1747, Lind divided his 12 ill seamen into six groups (P to W) of two each. All 12 shared a common diet for breakfast, lunch and dinner but each group received a different supplement as follows:
P:  quart of apple juice daily
Q: 25 drops of elixir vitriol (sulphuric acid and aromatics)
R: two spoonful’s of vinegar three times a day
S: concoction of herbs and spices
T: half-pint of sea water daily
W: two oranges and one lemon daily 
Which group(s) of seamen would have recovered fastest due to the supplement given?
(a) Q, R and S
(b) P and W
(c) P, W and T
(d) P, W and T

Answer : C

Question. Given below is a doctor's advice to a person:  1. Get your blood glucose levels checked regularly.2. Control your diet 3. Exercise regularly.  4. Take medication without fail.  The person to whom this advice is given is MOST likely to be
(a) a growing child
(b) a person suffering from diabetes
(c) a pregnant woman
(d) an athlete

Answer : B

Question. The blood glucose level found in urine samples of 4 patients P, Q, R and X at periodic intervals after consumption of a glass of orange juice are shown in the graph below.(mg/dl - milligrams per decilitre)
What is patient X likely to be suffering from?

(a) Diabetes
(b) Anaemia
(c) High Cholesterol
(d) Hypertension

Answer : A

Question. The chamber of the heart that has the thickest and strongest muscles is the one that-
(a) pumps blood to the lungs
(b) receives blood from the head
(c) pumps blood to the body
(d) receives blood from the lungs

Answer : C

Question. Vikram and Ana measure the number of breaths they take per minute while doing different activities. Study these and answer the question.
Which of these is a valid conclusion from this data?

(a) The rate of respiration is more for girls than boys.
(b) The rate of respiration increases with increased physical activity.
(c) The rate of respiration decreases with the age of the person.
(d) The rate of respiration decreases with the age of the person.

Answer : B

Question. Vikram and Ana measure the number of breaths they take per minute while doing different activities. Study these and answer the question.
The increase in rate of respiration observed probably serves what purpose?

(a) More glucose is delivered to the muscles as their energy source.
(b) More haemoglobin is delivered to the muscles as their energy source.
(c) More oxygen is delivered in order to break down glucose to do work.
(d) More carbon dioxide is delivered in order to break down glucose to do work.

Answer : C

Question. On a hot day, why do we feel more thirsty than usual?
(a) Because the food eaten has to be properly digested.
(b) Because our body temperature rises.
(c) Because we lose more water due to perspiration (sweating).
(d) Because the digestive system dries up in the heat.

Answer : C

Question. In the setups shown, two vessels of different sizes are filled with water as shown. The two vessels are connected by a tube. When the stopcock is opened, in which case will water flow from the vessel on the left to the vessel on the right?

Answer : B

Question. What happens when air is pumped into a cycle tube using a pump?
(a) Air expands in the tube.
(b) Air is compressed in the tube.
(c) Air is cooled in the tube.
(d) There is no change in any of these properties of air.

Answer : B

Question. Pankaj wants to empty a new and completely filled tin of oil. He thinks that he will make hole(s) on the top of the tin and then empty it (as shown in the picture). What is the minimum number of holes he should make so that the oil flows properly from the tin?

Answer : B
 

Question. Define adolescence.
Answer: The period of life, when the body undergoes changes, leading to reproductive maturity, is called adolescence. The period of adolescence is normally 11 years to 19 years.

Question. What is menstruation? Explain.
Answer: The cyclic flow of blood and mucus along with inner lining of uterus in case of not fertilization of egg from the female body is called menstruation. Each month uterus prepares itself to receive the fertilized egg. If fertilization do not occurs the inner ling breaks away and comes out through vagina for 3-5 days.

Question. What is the term used for secretions of endocrine glands responsible for changes taking place in the body?
Answer: Hormones.

Question. List changes in the body that take place at puberty.
Answer: The onset of puberty brings about:
(i) Growth of the reproductive organs which begin to function.
(ii) Hair growth at various places of the body. Breasts develop in girls and facial hairs appear in boys.
(iii) Voice of the boys becomes hoarse as voice box enlarges during adolescence.

Question. Prepare a table having two columns depicting names of endocrine glands and hormones secreted by them.
Answer: 

Question. What are sex hormones? Why are they named so? State their function.
Answer: The chemical substances produced by the sex organs are called sex hormones. They are named so because they control the sexual activities and are secreted by males and females separately.
Estrogen: This hormone is responsible for the development of secondary sexual characters in females like enlargement of breasts, development of female reproductive organs etc.
Testosterone: this hormone brings the secondary sex character in boys such as the growth of beard, the voice becomes hoarse, development of the reproductive organs etc.

Choose the correct option.

Question. The right meal for adolescents consists of
(a) chips, noodles, coke.
(b) chapati, dal, vegetables.
(c) rice, noodles and burger.
(d) vegetable cutlets, chips and lemon drink.
Answer: B

Question. Adolescents should be careful about what they eat, because:
(a) proper diet develops their brains.
(b) proper diet is needed for the rapid growth taking place in their body.
(c) adolescents feel hungry all the time.
(d) taste buds are well developed in teenagers.
Answer: B

Question. Reproductive age in women starts when their
(a) menstruation starts.
(b) breasts start developing.
(c) body weight increases.
(d) height increases.
Answer: A

Question. 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. The growing voice box in boys can be seen a protruding part of the throat called Adam’s apple.
(b) Secondary sexual characters- Those characters which are visible more apparently and help in distinguishing a male from a female are called secondary sexual characters. For example, in girls, breasts and in boys facial hairs i.e., moustache and beard.
(c) Sex determination in the unborn baby- Human beings have 23 pairs of chromosome. One pair of male (XY) and one pair of chromosome in female (XX) are called sex chromosome. When the sperm containing Y chromosome fuse with egg the sex of baby is male and when X chromosome containing sperm fertilse the egg the sex of baby is female. 

Question. Word game : Use the clues to work out the words.
Across
3. Protruding voice box in boys -- Adam’s apple
4. Glands without ducts -- Endocrine
7. Endocrine gland attached to brain -- Pituitary
8. Secretion of endocrine glands -- Hormone
9. Pancreatic hormone -- Insulin
10. Female hormone -- Estrogen
Down
1. Male hormone -- Testosterone
2. Secretes thyroxine -- Thyroid
3. Another term for teenage -- Adolescence
5. Hormone reaches here through blood stream -- Target site
6. Voice box -- Larynx
7. Term for changes at adolescence – Puberty.  

L-10

Reaching the age of Adolescence

1. After studying the following diagram, determine the sex of the child

2. Complete following table :
   Hormone                     Gland secreting the hormone
Thyroxine .........................................
......................................... Pancreas
Growth Hormone ........................................
......................................... Testis
Estrogen ........................................

3. Fill in the blanks -

i) Reaching the age of adolescence, the protruding part of the throat in boys is called ____________.

ii) Hormone secreted by testis is _________________.

iii) Stoppage of menstruation is called _________________.

iv) Pituitary gland secretes a hormone _____________. responsible for the growth.

4. Write any three secondary sexual characters in boys and girls on reaching the age of adolescence.
Boys                                             Girls
i) ................................... ....................................
ii) ................................... ....................................
iii) ................................... ....................................

5. During the period of adolescence, children should eat which type of food and which not.
        Should eat                        Should be avoided
i) .................................   1) .........................................
ii) .................................  2) .........................................
iii) ................................. 3) .........................................
iv) ................................. 4) .........................................
Fruits, Burger, Milk, Pizza, Chocolates, Pulses, Chips, Vegetables.

6. Write a slogan on junk - food

Q.1 Define the following:
i) adolescence
ii) hormones
iii) puberty
iv) endocrine glands
v) target site
vi) chromosomes
vii) Menstruation
viii) Menarche ix) Menopause

Q.2 Mention the age group for adolescence. Why this period is also called as teenager period?

Q.3 What stage of growth marks the cessation of puberty?

Q.4 Mention some changes that take place in an individual during puberty?

Q.6 At what age human beings attain full height?

Q.7 Comment on the pattern of growth in human beings during puberty.

Q.8 How does intake balanced diet affect the growth of an individual during puberty?

Q9 What are the differences noticed between the growth patterns of boys and girls at the stage of puberty?

Q.10 What is Adam’s apple?

Q11 How is the voice of girls different than that of the boys and why?

Q12 What are sebaceous glands? How are these glands affected during puberty?

Q13 What are the changes that take place in the reproductive organs of the boys and girls during puberty?

Q14 Mention the intellectual and emotional changes that take place in an individual during puberty?

Q15 What do you mean by secondary sexual characteristics? Mention a few of them.

Q16 Name the hormone secreted by testes and ovaries.

Q17 Mention the changes that take place in the endocrine glands of male and female human beings.

Q18 Name the endocrine gland which controls the secretions from other glands.

Q19 What role do hormones play in the onset of puberty?

Q20 Write the main characteristic features of menstrual cycle?

Q21 Mention the changes that take place in the uterus if it receives an unfertilsed egg from the fallopian tube?

Q22 Explain how the sex of an individual is determined?

Q23 Draw a neat diagram to show the location of various endocrine glands in our body.

Q24 What is adrenalin ? What is its funtion?

Q25 Why should we plan the diet of an adolescent with great care?

Q26 Why should a teenager be highly careful about the cleanliness of his/her body?

Q27 Fill in the blanks:

a) Adolescents become capable of reproduction when their --------- and ------- begin to produce gametes

b) In human females th reproductive phase of life begins at---------- and lasts till the age of------- years.

c) -------- no. of chromosomes are present in the human gametes

d) -------- and------- are sex chromosomes.

e) An ovum has -----sex chromosome while a sperm has -----sex chromosome.

f) The gametes posess only ------- set of chromosomes.

g) Human sperms are of --------- types as they carry either --------or-------- sex chromosomes.

h) -------- glands maintain salt balance in the body.

i) Adrenalin is secreted from the ---------- gland.Growth hormone is secreted from the --------- gland.

j) The changre from larva to adult is called---------

k) Deficiency of ----------mineral leads to goiter.

l) ------------ are considered to be protective foods.

Hots and values based -

1. Mrs . Ramesh does not use iodised salt in the food she cooks at home .Mr. Ramesh suggested her to use iodised salt to keep good health of the family.
What values are associated with such suggestion.

2. Rahul goes to gym for a workout everyday. How is it values in his life.

3. Anmol lives near a pond . He always notices tadpoles in the water but no frogs .
What do you think is the reason?

Fill in the blanks :

1.The period of life, when the body undergoes changes, leading to reproductive maturity is called __________.

2.The age at which reproductive organs become functionally active is called _____________.

3.Increase in height occurs during __________.

4._____________ are external characters which are directly not involved in the process of reproduction.

5.The changes which occur during adolescence are controlled by ______________.

6.The hormones are produced in special organ are called _______________.

7.Endocrine glands are also called ______________ glands.

8.In frog metamorphosis is controlled by ______________ hormone.

Answer the following :

1. Name the sex hormone in humans.

2. Name the disease caused due to deficiency of the hormone thyroxine.

3. Name the hormone produced by the adrenal gland.

4. Name the master gland.

5. What are the type of sex hormones produced by males ?

6. How many pairs of chromosomes as human body cell contain ?