STUDENT SUPPORT MATERIAL - CLASS 12

3 (a) 2n, n
4 (c)Testis
5 (c) A-Trophoblast, B –Inner cell mass
6 (c) hCG
7 (c) 7 days
8 (b) Causes strong uterine contractions during parturition process
9 (a) Prostate gland
10 (d) requirement of low temperature for spermatogenesis.
11 (c) Seminiferous tubules
12 (c) 4
13 (a) Whole sperm
14 (d) Testis, testosterone
15 (c) Ovulation
16 (a) Secondary oocyte stage
17 (b) Modifies into corpus albicans
18 (a) Ampullary – isthmic junction
19 (c) LH
20 (a) FSH
21 (d) Blastocyst – Uterine wall
22 (c)
23 (a)
24 (c)
25 (c)

ASSERTION REASON TYPE QUESTIONS

a. Both Assertion and Reason are true and Reason is the correct explanation of
Assertion.

b. Both assertion and reason are true, but the reason is not the correct
explanation of the assertion.

c. Assertion is true but reason is false.

d. Both assertion and reason are true, and reason is correct explanation of the
Both assertion and reason are false.

1.Assertion: In human male, testes are extra abdominal and lie in scrotal
sac.

Reason: Scrotum acts as thermoregulator and keeps testicular
temperature lower by 20 c for normal spermatogenesis.

2. Assertion: Urethra in human male acts as urinogenital tract.

Reason: Urethra carries only urine while sperms are carried by vasa
deferentia only.

3. Assertion: Fallopian funnel of oviduct is with finger like fimbriae.Reason:
Graafian follicle of ovary is with secondary oocyte hanging in cavity called
antrum.

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4. Assertion; Corpus luteum degenerates if the ovum remains unfertilized.

Reason: Corpus luteum secretes progesterone which maintains the pregnancy.

5. Assertion: Vagina acts as copulation canal and fertilization canal.

Reason: Both insemination and fusion of gametes occur in vagina of
female.

6. Assertion: The reason present outside the seminiferous tubules in testis is
called as interstitial space

Reason: Leydig cells synthesize and secrete testosterone hormone.

7. Assertion: Oxytocin helps in parturition so it’s called as birth hormone.

Reason: Oxytocin acts upon uterine muscles and causes birth of baby.

8. Assertion: The secretory phase of menstrual cycle is called as luteal phase.

Reason: During luteal phase corpus luteum develops and secretion of
progesterone starts.

9. Assertion: All copulations do not result into fertilization and pregnancy.

Reason: Fertilization can occur only if the ovum and sperms reach to
ampullary – isthmic junction simultaneously.

10. Assertion: Human egg contains small amount of yolk.

Reason: Developing embryo depends upon the mother body for it’s
nutrition, not on the yolk.

11. Assertion: After the process of ovulation the empty Graafian follicle transforms
into corpus luteum.

Reason: Corpus luteum is formed due to the influence of anterior

pituitary hormones LH and LTH.

12. Assertion: At the end of pregnancy the ratio of estrogen to progesterone
increases and it causes initiation of fetal ejection reflex.

Reason: Due to rise in estrogen – progesterone ratio secretion of
oxytocin starts which causes uterine contractions which leads to parturition.

13. Assertion: In human female reproductive system uterus is inverted pear shape.

Reason: The inner lining of uterus which is glandular is called as
endometrium.

14. Assertion: Each primary oocyte gives rise to single functional female gamete.

Reason: Meiosis in primary oocyte leads to formation of one cell only
which functions as ovum.

15. Assertion: Corpus luteum is present in proliferative phase of menstrual cycle.

Reason: In proliferative phase high concentration of progesterone is
present.

16. Assertion: Regular menstrual cycle is an indicator of healthy reproductive
phase.

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Reason: Menstrual cycle occurs throughout the reproductive phase of a
normal female.
17. Assertion: During the process of oogenesis polar bodies are formed.
Reason: The primary function of formation of polar body is to bring haploidy
of ovum.
18. Assertion: FSH hormone helps in spermatogenesis.

Reason: It stimulates the Sertoli calls to secret some factors which are
helpful in spermatogenesis.
19. Assertion: During follicular phase of menstrual cycle estrogen level is high.

Reason: During follicular phase corpus luteum secretes large amount of
estrogen.
20. Assertion: From day 10 to 17 is called as fertile period of menstrual cycle.

Reason: Chances of fertilization are very high during this phase.

ANSWERS

1 2345
AC B AD
6 7 8 9 10
BA A AA
11 12 13 14 15
AA BCD
16 17 18 19 20
AA A C A

CASE BASED QUESTIONS
1.The following incomplete flow chart shows the influence of hormones on the process
of gametogenesis in human males.

i.In above flow chart A is
A. Androgens
B. Progesteron
C. FSH
D. LH

53

ii.Which process is B?
A. Oogenesis
B. Ovulation
C. Spermatogenesis
D. Fertilisation

iii.Name the cells shown as box C which are target of FSH hormone
A. Laydig cells

B. Interstitial cells
C. Spermatogonia cells
D. Sertoli cells
iv. What is the name of process shown as D?
A. Oogenesis
B. Spermatogenesis
C. Ovulation
D. Fertilisation
v.In human males
A. Maturation of sperms starts at puberty
B. Sperm production starts at puberty
C. Second meiosis is completed
D. None of above

2. A lady has 28 days reproductive cycle. Observe the diagram of her
reproductive cycle and answer following question:

i.Around which day of menstrual cycle chances of conceiving is higher?
1. 1-5 days
2. 21-28days
3. Around 14days
4. Around 28 days

ii. Higher level of progesterone can be related to which event of uterus?

54

1. Contraction of myometrium
2. Shedding of endometrium
3. Formation of corpus luteum
4. Increase in thickness of endometrium

iii. From where is Progesterone secreted?
1. Pituitary
2. Hypothalamus
3. Secondary oocyte
4. Corpus luteum

iv. Assertion: Menstrual cycle stops during pregnancy.

Reason: High level of progesterone helps in maintaining pregnancy.

(a) Both assertion and reason are true, and reason is correct
explanation of the assertion.

(b)Both assertion and reason are true, but the reason is not
the correct explanation of the assertion.
(c)Assertion is true but reason is false.

(d)Both assertion and reason are false.

v.In which phase of the menstrual cycle the thickness of the uterine wall is
maximum?

(a) Bleeding phase

(b) proliferative phase

(c) Luteal phase

(d) none of them

3. Humans are sexually reproducing and viviparous it involves male and
female reproductive system. Male reproductive system is located in pelvis
region. It includes a pair of testis along with accessory ducts glands and
external genitalia. Each testis has about 250 compartment called testicular
lobules. Each testicular lobule has one to three seminiferous tubules in which
sperm are produced. Region outside the seminiferous tubules called interstitial
space where leydig’s cells are located.

i. Which one of the following is not a duct of reproductive system?
(a) Seminiferous tubule
(b) Urethra
(c) Ureter
(d) both ureter and urethra

ii.Which one of the following located in scrotum
(a). urethra
(b). ureter
(c). testis
(d). ejaculatory duct

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iii.Identify the correct sequence of ducts
(a)seminiferous tubules, urethra, vasa efferentia, epididymis, vas
deferens

(b)seminiferous tubules, vasa efferentia, epididymis, vas deferens,
urethra

(c)seminiferous tubules, epididymis, vas deferens, urethra, vasa
efferentia

(d)vasa efferentia ,seminiferous tubules, epididymis, vas deferens,
urethra

iv.The nutritive cells found in seminiferous tubules are
(a)leydig’s cells
(b)sertoli cells
(c) male germ cells
(d)chromaffin cells

A. v.Which of the following is a male accessory gland?
B. (a)Seminal vesicle

(b)Ampulla
(c)Prostate gland
(d) a and c both

3. The primary sex organs are testis in the males and ovaries in the female
produce gametes i.e. sperm and ovum respectively by the process called
gametogenesis. In male spermatogenesis i.e formation of sperms from
spermatogonia start at puberty. Each primary spermatocyte which is diploid develop
from spermatogonia, is diploid undergoes meiosis I to produce secondary
spermatocytes. The secondary spermatocyte undergoes meiosis II to produces
spermatids.
i.Which one of the following cells has 46 no. of chromosome?
a. spermatogonia
b. secondary spermatocyte
c. spermatids
d. Ova

ii. How many sperms are formed from 4 secondary spermatocytes?

a. 8
b. 16
c. 32
d.4
iii. Which of the following cells meiosis I takes place?
a. Secondary spermatocytes
b. Primary spermatocytes
c. Spermatid
d. Leydig’s cells

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iv. In spermatogenesis, reduction division of chromosomes occurs during
conversion oF

a. Spefmatogonia to primary spermatocyte

b. Primary spermatocyte to secondary spermatocytes

c. Secondary spermatocytes to spermatids

d. Spermatids to sperms

v. The ploidy level of primary spermatocyte is
a. 2n
b. n
c. 3n
d. 4n

4. Process of implantation is embedding of the blastocyst into the endometrial
lining of uterus. Blastocyst is like a ball of cells with a large fluid filled cavity called
blastocoel. The blastomeres in a blastocyst are arranged as outer layer called as
trophoblast and inner cell mass. Inner cell mass consists of stem cells.

(i). In which stage of development of embryo implantation occurs in
humans?
a. Early embryo
b. Morula
c. Zygote
d. Blastocyst

(ii). Assertion : Blastocyst undergoes gastrulation and forms 3 germ
layers during embryogenesis

Reason : This occurs by cell movement which gives new shape
and morphology to embryo.
a. Both A and R are true and R is the correct explanation of A.
b. Both A and R are true but R is not correct explanation of A.
c. A is true but R is false.
d. Both A and R are false
(iii). On which day of fertilization implantation occurs in humans?

a. Gastrula
b. Blastocyst
c. Morula
d. At any stage as its not certain
(iv). What is the fate of inner cell mass?
a. It’ll develop as placenta
b. It’ll secrete hormones
c. It’ll form embryo
d. None of the above
(v). The solid ball of cells produced by repeated cleavage is called as
a. Gastrula
b. Blastula

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c. Nurula
d. Morula

ANSWERS

1 (i) - a 1 (ii) - c 1 (iii) - d 1 (iv) -b 1 (v)- b
2 (i)-c 2 (ii) –d 2 (iii)-d 2 (iv) –a 2 (v)- C
3 (i) –c 3 (ii) - c 3 (iii) –b 3 (iv)–b 3 (v) - d
4 (i) –a 4(ii)- a 4 (iii)- b 4 (iv) -b 4 (v) – a
5 (i) - d 5 (ii) - c 5 (iii)-b 5 (iv)-c 5 (v)-d

CHECK YOUR GRASP

Time: 90 minute Maximum Marks: 35
General Instructions:
i.All questions are compulsory.

ii.The question paper has three sections: Section A- MCQ, Section B -Assertion –
Reason type questions and Section C- Case study base questions. There are 27
questions in the question paper, Section–A has 15 questions of 1 mark each
and. Section–B has 10 questions of 1 mark each and Section–C has 2 questions
of 5 marks each.

iii.There is no overall choice.
Section-A

1. Which fetal membrane and part of female reproductive system take
part in the formation of placenta?

a. Amnion and uterine tissue

(b) Chorion and Uterine tissue.
(c) Chorion and muscles
(d) Yolk sac and uterine lining

2. Which out of the following is the role of trophoblast?

a. It provides support to embryo

(b) It helps in Implantation.

(c) It secretes hormones

(d) It secretes food

3. In human female during the menstrual cycle ovulation occurs
a. at the mind secretory phase

(b) just before the end of the secretory phase
(c) at the beginning of the proliferative phase
(d) at the end of the proliferative phase.

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4. Just after ovulation, the mammalian egg is covered by a membrane called
(a) chorion
(b) zona pellucida
(c) corona radiata
(d) vitelline membrane.

5. In the following events which one is correctly matched with the time period in a
normal menstrual cycle?

(a) Release of egg: 5 th day
(b) Endometrium regenerates : 5 – 10 days
(c) Endometrium secretes nutrients for implantation: 11 – 18 days
(d) Rise in progesterone level : 1 – 15 days

6. In case mammalian ovum is not fertilized, which one of the following is unlikely
?

(a) Disintegration of corpus luteum occurs.
(b) Progesterone secretion decreases.
(c) Estrogen secretion increases.
(d) Primary follicle start to develop.

7. Which part of the sperm is important role for penetrating the egg membrane ?
(a) Polysome
(b) Tail
(c) Middle piece
(d) Acrosome

8.Besides activating the egg another role of a sperm is to contribute
(a) RNA
(b) mitochondria
(c) DNA
(d) ribosomes.

9.The process of differentiation of sperms from spermatids is called as
(a) Spermiation
(b) Spermiogenesis
(c) Spermatogenesis
(d) None of above

10. In sperm acrosomal reaction occurs due to
(a) its contact with zona pellucida of the ova
(b) reactions going on within the uterine environment of the female
(c) reactions going on within the epididymal environment of the male
(d) hormones produced in the uterus.

11. Which of the following contains 23 chromosomes?
(a) Zygote
(b) Spermatogonia
(c) Secondary oocyte
(d) Oogonium

59

12. Human placenta acts as an endocrine gland. Which hormones is not secreted
by it ?

(a) hCG
(b) Estrogens
(c) Progesterone
(d) LH
13. Urethral meatus is
(a) urinogenital duct
(b) the opening of vas deferens into urethra
(c) external opening of the urinogenital duct
(d) muscles present around the urinogenital duct.

14.At the time of ovulation, the membranous covering present around ovum is
(a) chorion.
(b) zona radiata
(c) zona pellucida
(d) corona radiata

15.Temperature of the scrotum which is necessary for the functioning of testis is
always _______lesser than the body temperature.

(a) 2°C
(b) 6°C
(c) 10°C
(d) 8° C

16. The birth control device not used by women is

(a) Diaphragm

(b) Condoms

(c) Oral pill

(d) None of above

17. Test tube baby is a technique where

(a) Zygote is taken from oviduct, cultured and then implant

(b) Ovum is taken out then fertilized and implanted

(c) Sperm and ovum are fused and zygote is developed in a test tube.

(d) None of above

18. A method of birth control is

(a) ZIFT

(b) GIFT

(c) IUCD

(d) IVF-ET

19. Which out of the following is related to males?

(a) Vasectomy

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(b) Oral pills
(c)Tubectomy
(d)None of these
20. Lactational amenorrhea is related to
(a) Temporary and natural method of contraception
(b) Absence of menstruation
(c) An STD
(d) Permanent contraception method

21. Assertion: In human male, testes are extra abdominal and lie in scrotal sac.

Reason: Scrotum acts as thermoregulator and keeps testicular
temperature lower by 20C for normal spermatogenesis.

(a) Both assertion and reason are true, and reason is correct
explanation of the assertion.
(b) Both assertion and reason are true, but the reason is not the
correct explanation of the assertion.
(c) Assertion is true but reason is false.
(d) Both assertion and reason are false.

22.Assertion: Urethra in human male acts as urinogenital tract.
Reason: Urethra carries only urine while sperms are carried by vasa
deferentia only.

a. Both assertion and reason are true, and reason is correct explanation of the
assertion.
b. Both assertion and reason are true, but the reason is not the correct
explanation of the assertion.
c. Assertion is true but reason is false.
d. Both assertion and reason are false.

23. Assertion: Each seminiferous tubule is lined on its inside by three types of
cells. Reason: These cells are male germ cells, sertoli cells and leydig’s cells.
a. Both assertion and reason are true, and reason is correct explanation of the
assertion.
b. Both assertion and reason are true, but the reason is not the correct
explanation of the assertion.
c. Assertion is true but reason is false.
d. Both assertion and reason are false.
24. Assertion: The embryo with 8 to 16 blastomeres is called morula.

Reason: The morula continues to divide and transform into trophoblast.

61

a. Both assertion and reason are true, and reason is correct explanation of the
assertion.

b. Both assertion and reason are true, but the reason is not the correct
explanation of the assertion.

c. Assertion is true but reason is false.

d. Both assertion and reason are false.

25. Assertion: Interstitial cells are present in the interstitial space outside
the seminiferous tubule.

Reason: Interstitial cells provide nutrition to the sertoli cells.

a. Both assertion and reason are true, and reason is correct explanation of the
assertion.

b. Both assertion and reason are true, but the reason is not the correct
explanation of the assertion.

c. Assertion is true but reason is false.

d. Both assertion and reason are false.

CASE BASE QUESTIONS
26.Humans are sexually reproducing and viviparous it involves male and
female reproductive system. Male reproductive system is located in pelvis
region. It includes a pair of testis along with accessory ducts glands and
external genitalia. Each testis has about 250 compartment called testicular
lobules. Each testicular lobule has one to three seminiferous tubules in which
sperm are produced. Region outside the seminiferous tubules called interstitial
space where leydig’s cells are located.

1.Which one of the following is not a duct of reproductive system?

a. Seminiferous tubule
b. urethra
c. Ureter
d. Both ureter and urethra

2.Which one of the following located in scrotum

a. Urethra
b. ureter
c. Epididymis
d. ejaculatory duct

3.Identify the correct sequence of ducts

a. Seminiferous tubules, urethra, vasa efferentia, epididymis, vas deferens
b. Seminiferous tubules, vasa efferentia, epididymis, vas deferens, urethra
c. Seminiferous tubules, epididymis, vas deferens, urethra, vasa efferentia
d. Vasa efferentia, seminiferous tubules, epididymis, vas deferens, urethra

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4.The nutritive cells found in seminiferous tubules are

a. Leydig’s cells
b. sertoli cells
c. Male germ cells
d. chromaffin cells

26. The primary sex organs are testis in the males and ovaries in the female
produce gametes i.e. sperm and ovum respectively by the process called
gametogenesis.In male spermatogenesis i.e formation of sperms from
spermatogonia start at puberty. Each primary spermatocyte which is diploid develop
from spermatogonia, is diploid undergoes meiosis I to produce secondary
spermatocytes. The secondary spermatocytes undergo meiosis II to produces
spermatids.

1. Which one of the following cell has 46 no. of chromosomes?
a. Spermatogonia
b. secondary spermatocyte
c. Spermatids
d. ova

2.How many sperms are formed from 4 secondary

spermatocytes?

a. 8
b. 16
c. 32
d. 4
3.Which of the following cells meiosis I takes place?

a. Secondary spermatocytes
b. Primary spermatocytes
c. Spermatid
d. leydig’s cells

4.In spermatogenesis, reduction division of chromosomes occurs during conversion of

a. Spermatogonia to primary spermatocyte
b. Primary spermatocyte to secondary spermatocytes
c. Secondary spermatocytes to spermatids
d. Spermatids to sperms

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SOLUTION

Question Marks
Number
1 (b) Chorion and Uterine tissue.
It helps in implant action
2
(d) at the end of the proliferative phase.
3 (c) corona radiata
4 (b) Endometrium regenerates : 5 – 10 days
5 (c) Estrogen secretion increases.
6 (d) Acrosome
7 (c) DNA
8 (b) Spermiogenesis
9 (a) its contact with zona pellucida of the ova
10 (c) Secondary oocyte
11 (d) LH
12 (c) external opening of the urinogenital duct
13 (d) Corona radiata
14 (a) 2°C
15 (d)None of above
16 (b) Ovum is taken out then fertilized and implanted
17 (c)IUCD
18
19 (a) Vasectomy

20 (a) Temporary and natural
method of contraception
21 (a)
22 (b)
23 (d)
24 (c)
25 (c)
26 i-(c)
26 ii-(c)
26 iii-(b)
26 iv-(b)
27 i-(a)
27 ii-(b)
27 iii-(a)
27 iv-(b)

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CHAPTER 4. REPRODUCTIVE HEALTH

Reproductive health simply refers to healthy reproductive organs with
normal functions. According to the World Health Organisation (WHO),
reproductive health means a total well-being in all aspects of reproduction,
i.e. physical, emotional, behavioural and social.
The improved reproductive health of society requires following
factors:

i. Better awareness about sex-related matters.
ii. Increased number of medically assisted deliveries and better postnatal

careleading to decreased maternal and infant mortality rates.
iii. Increased number of couples with small families.
iv. Better detection and cure of STDs.
v. Overall increased medical facilities for all sex-related problems.

Some of the measures taken for awareness of reproductive health are:

i. The family planning programmes.
a. Major tasks of RCH programme are:
b. Creating awareness among the people about reproduction related
aspects.
c. Providing facilities and support for building up a reproductively healthy
society

ii. In schools, introducing sex education (Adolescents should be informed
about reproductive organs, adolescence and related changes, safe and
hygienic sexual practices, Sexually Transmitted Diseases (STDs), AIDS,
etc.).

iii. Married couple or those in marriageable age group should be educated about
available birth control options, care of pregnant mothers, postnatal care of
the mother and child, importance of breast feeding, equal opportunities for
the male and the female child, etc.

iv. Successful implementation of action plans like providing medical
assistance and care to reproduction-related problems, pregnancy,
delivery, STDs, abortions, contraception, Menstrual problems, infertility,
etc.

v. Statutory Ban on amniocentesis.

The benefits of amniocentesis are the diagnosis of chromosomal abnormalities and
developmental disorders of foetus. However, it is being misused for sex-
determination of foetus that leads to female foeticides. Therefore, statutory ban on
amniocentesis for sex determination keeps check on female foeticides.

Population Explosion:

The tremendous increase in size and growth rate of population is called
population explosion. It occurs due to increased health facilities and better
living conditions.
Reasons of population explosion are:

 Decrease death rate.
 Declined maternal mortality rate.
 Decreased infant mortality rate.
 Increase in number of people in reproductive age.

65

According to the 2001 census report, the population growth rate was around 1.7%,i.e.
17/1000/year. By this rate, our population could double in 33 years.

Methods to prevent population explosion are:

(i) Raising the marriageable age to 18 years for females and 21 years for
males.

(ii) Couples with small families should be given some incentives.

(iii)Birth control is an important step to control the population growth by
motivating smaller families to use contraceptive methods.
Contraceptive methods are ideal if they are used friendly, easily available,
effective, reversible with no side effects and non-interfering with the sexual

drive, desire and the sexual act.
There are several methods of birth control. These are categorized mainly
as follow:

(i) Natural method of birth control involves avoiding chances of sperm
and ovum meeting. It can be achieved by:

(a) Periodic abstinence in which couples avoid coitus from day
10-17 (Fertile period) of the menstrual cycle. In this period,
ovulation is expected to occur and chances of fertilisation are very
high. Also called as rhythm method or natural family planning.
(b) Coitus interruptus also called ‘rejected sexual intercourse’ or
‘pull-out’ method or withdrawal. In this method, the penis is
withdrawn, from the vagina just before ejaculation.
(c) Lactational amenorrhea refers to the absence of menstruation
during the period of lactation following parturition. Because
ovulation does not occur in this period, the chances of conception
are none. This method is reliable for a maximum period of six
months after delivery.
(ii) Barrier methods are based on prevention of ovum and sperm from
physically meeting with the help of barriers. Barriers may be chemical or
mechanical.
a. Condoms are mechanical barriers made of thin rubber or latex sheath to cover
the penis in male or vagina and cervix in females which prevent meeting of sperm
and ova. Condoms also provide protection sexually transmitted diseases. They are
disposable and can be self-inserted and thereby give privacy to the user.
b. Diaphragms, cervical caps and vaults are also mechanical barriers, made of
rubber that is inserted into the female reproductive tract to cover cervix during
coitus. They are reusable.
c. Spermicidal creams, jellies and foams are chemical barriers, usually used
along with these barriers to increase their contraceptive efficiency.
(iii) Intra Uterine Devices (IUDs) are the devices introduced in
the uterus through vagina by doctors or expert nurses. These are of
following types:
a. Non-medicated IUDs, e.g. lippes loop.

b. Copper-releasing IUDs, e.g. Cu-T, Cu-7, multiload 375.

c. Hormone-releasing IUDs, e.g. progestasert, LNG 20.

IUDs prevent contraception in the following ways:

a. Increase phagocytosis of sperms within the uterus.

66

b. Some IUDs suppress sperm motility and fertilizing ability of sperm by releasing
copper ions.

(c)The hormone releasing IUDs make uterus unsuitable for
implantation and make the cervix hostile to sperms. IUDs are
ideal contraceptives for females who want to delay pregnancy. It
is one of most widely accepted contraception method in India.

(iv). Oral contraceptives are hormonal preparations in the form of pills.

(a)Pills are small doses of either progestogens or
progesterone- estrogen combinations.

(b) Oral pills alter/inhibit ovulation and implantation
and also modify the quality of cervical mucus to
prevent/retard entry of sperms.
c. Oral pills have to be taken daily for a period of 21 days

starting within the first five days of menstrual cycle.
 Saheli an example of oral contraceptive developed by scientists at Central

Drug Research Institute (CDRI) Lucknow, contains a non-steroid called
centchroman. It is a once-a-week pill, with very few side effects.

(v)Replants or injections are effective for longer period, although their
mode of action is similar to oral contraceptives. Progesterone alone or in
combination with estrogen is used by females as injections or implants under the
skin.

(vi) Emergency contraceptives included administration of
progesterone or progestogen-oestrogen combinations or IUDs within
72 hours of coitus. It has been found to be very effective to avoid
possible pregnancy due to rape or casual unprotected intercourse.
(vii)Sterilisation or surgical methods are used by male/female partner as a
terminal method to prevent any more pregnancies. These methods block the
transport of gametes and prevent contraception.
a. Vasectomy is applied in case of males. In this method, a small portion of vas
deferens is removed or tied up through an incision on the scrotum.
b. Tubectomy is applied in females, where a small part of Fallopian tubes is
removed or tied up through a small incision in the abdomen or through vagina.

Both of these techniques are highly effective but poorly reversible.
Medical Termination of Pregnancy (MTP) or induced
abortion is intentional or voluntary termination of pregnancy
before full term.

 The Government of India had legalized MTP in 1971 with some strict
conditions to avoid its misuse. These are important to check

67

indiscriminate and illegal female foeticides which are reported to be
high in India.
 MTPs are done in certain cases where pregnancy can be harmful and
even fatal either to the mother or the foetus or both, or duets failure
of contraceptive used during coitus or rapes.
 MTPs are considered relatively safe during the first trimester (up to 12
weeks) of pregnancy.
 During second trimester, MTPs are unsafe and could be fatal too.
 About 45-50 million MTPs are carried out in a year all over the
world. It has significant role in decreasing population though it
is not meant for that purpose.

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PRACTICE QUESTIONS

MCQ
1.RCH stands for

(a) Reproductive and complete health
(b) Regional and central health care
(c) Reproductive and child health care
(d) None of above
2. Which out of the following STDs does not affect organs?
(a) Gonorrhea
(b) Genital warts
(c) AIDS
(d) Syphilis

3. Which surgical method out of the following is used for contraception
(a) Castration
(b) Vasectomy
(c) Ovariectomy
(d) Hysterectomy

4. A contraceptive pill contains
(a) Combination of progesterone and estrogen
(b) Spermicidal salt
(c) Chemicals to prevent fertilisation
(d) Chemicals t0 abort embryo

5. In test tube baby program test tube babies are produced
(a) Inside a test tube
(b) Without fertilisation
(c) In vivo fertilisation
(d) In vitro fertilisation

6. Increase in IMR and decrease in MMR in a population will cause
(a) rapid increase in growth rate
(b) fall in growth rate
(c) no significant change in growth rate
(d) population explosion

7. Which out of the following contraceptives involve role of hormones
(a) Pills, Emergency contraceptives, Condoms
(b) Cu T, emergency contraceptives, pills
(c) Pills, emergency contraceptives, lactational amenorrhea
(d) Condoms, lactational amenorrhea, pills

8. Which of the following is a mechanical barrier used for birth control
(a) Copper-T
(b) Diaphragm
(c) Lippeloop
(d) Pills

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9.In contraceptive pills progesterone is responsible for
(a) Preventive fertilization
(b) Preventing Implantation
(c) Preventing clevage
(d) Preventing ovulation

10.Which of the following techniques is used in test tube baby programme
(a) Intra uterine insemination
(b) Gamete intrafallopian tranfer
(c) Intracytoplasmic sperm injection
(d) zygote intra fallopian transfer.

11.Which of the following is a copper releasing IUD?
(a) Diaphragm
(b) Multiload 375
(c) LNG-20
(d) Saheli

12.Oral contraceptive generally prevent pregnancy by
(a) Preventing implantation
(b) Preventing ovulation
(c) Killing of ovum
(d) Preventing fertilization

13.Which of the following is a hormone releasing intrauterine device
(a) Diaphragm
(b) Multiload 375
(c) LNG-20
(d) Saheli

14.Which statement is correct about ZIFT.
(a) Zygote is collected from a female donor and transferred to a fallopian tube
(b) Ovum is collected from a female donor and transferred to fallopian tube

(c) Zygote is collected from a female donor and transferred to a uterus

(d)Ovum is collected from a female donor and transferred to uterus

15.Emergency contraceptives are effective if used within
(a)72 hours of ovulation
(b)72 hours of implantation
(c) 72 hours of coitus
(d)72 hours of menstrual flow

16.Condoms are one of the most popular contraceptive because
(a) They do not interfere in coitus
(b) They prevent STD’s
(c) They are effective barriers for insemination
(d) All of the above

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17.In copper releasing IUD’s the role of copper ions is
(a) They prevent gametogenisis
(b) They suppress sperm motility and fertilizing capacity of sperm.
(c) They inhabit ovulation
(d) They inhabit implantation

18.If a couple is unable to have a child because male is having very low sperm
count.Which of the following technique will be suitable for him.

(a) Intrauterine tranfer
(b) GIFT
(c) ICSI
(d) Artificial insemination

19.Oral contraceptive pills function by inhibiting

(a) Reproduction
(b) Ovulation
(c) Implantation
(d) Fertilization

20.In invitro fertilization technique which of the following stage is transferred to the
fallopian tube

(a) Zygote or early embryo up to 8 celled stage
(b) Only Zygote
(c) Embryo up to 32 celled stage
(d) None of the above

21. Which ART method can help a lady to conceive if both her fallopian tubes are
blocked?

(a) SUJI
(b) IVF
(c) ZIFT
(d) GIFT

22. Which one of the following is not a copper releasing IUDs?
(a) LNG 20
(b) Cu T
(c) Lippes loop
(d) a and c both

23. Which of the following is not shown by an ideal contraceptive?
(a) irreversible
(b) easily available
(c) user friendly
(d) effective with least side effects

24. Which part of the female reproductive system remains blocked after tubectomy?
(a) Fallopian tube

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(b) Oviduct
(c) Cervix
(d) Uterine cavity

25. In IVF technique zygote or early embryo is transferred into
(a) Cervical canal
(b) Uterus
(c) Fallopian tube
(d) Vagina

ANSWERS
1. (c) Reproductive and child health care
2. (c) AIDS
3. (b) Vasectomy
4. (a) Combination of progesterone and estrogen
5. (c) Invitro fertilization
6. (c) No significant change in growth rate
7. (c) Pills, emergency contraceptives, lactational amenorrhea
8. (b) Diaphragm
9. (d) Preventing ovulation
10. (d) zygote intra fallopian transfer.
11. (b) Multiload 375
12. (b) Preventing ovulation
13 . (c) LNG-20
14. (a) Zygote is collected from a female donor and transferred to a fallopian tube
15. (c) 72 hours of coitus
16. (d) All of the above
17. (b) They suppress sperm motility and fertilizing capacity of sperm.
18. (d) Artificial insemination
19. (b) Ovulation
20. (a) Zygote or early embryo upto 8 celled stage
21. (b) IVF
22. (d) a and c both
23. (a) Irreversible
24. (a) Fallopian tube
25. (c) Fallopian tube

ASSERTION REASON QUESTIONS
1.Assertion: A person should be considered as reproductively healthy if
he/she has a healthy reproductive system although he/she is emotionally
imbalanced.

Reason: Above statement about reproductive health was given by WHO.
A. If both assertion and reason are true and reason is correct explanation of
assertion.
B. If both assertion and reason are true and reason is not correct explanation of
assertion.
C. If assertion is true but reason is false
D. If both assertion and reason are false

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2. Assertion: Test tube baby program has raised several legal problems.

Reason: It involves in vitro fertilization followed by embryo transfer.

A. If both assertion and reason are true and reason is correct explanation of
assertion

B. If both assertion and reason are true and reason is not
correct explanation of assertion
C. If assertion is true but reason is false

D. If both assertion and reason are false.

3.Assertion: Coper – T is an effective contraceptive device in human females.

Reason: Coper- T prevents passage of sperms from vagina upwards into
fallopian tubes.

A.If both assertion and reason are true and reason is correct explanation
of assertion

B.If both assertion and reason are true and reason is not correct explanation
of assertion

C.If assertion is true but reason is false

D.If both assertion and reason are false
4.Assertion: Test tube baby has raised several legal problems

Reason: It involves in vitro fertilization followed by embryo transfer

A.If both assertion and reason are true and reason is correct explanation of
assertion

B.If both assertion and reason are true and reason is not correct
explanation of assertion

C.If assertion is true but reason is false

D.If both assertion and reason are false.

5.Assertion: Saheli is an oral contraceptive pill which is to be taken once in a
week and it shows few side effects.

Reason: Saheli is a non - steroid combination.

A.If both assertion and reason are true and reason is correct explanation of
assertion

B.If both assertion and reason are true and reason is not correct
explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false.

6.Assertion: During active lactation period generally a woman does not
conceive.

Reason: In women prolactin is responsible for initiation and maintenance of
lactation.

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A.If both assertion and reason are true and reason is correct explanation of
assertion

B.If both assertion and reason are true and reason
is not correct explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false.

7.Assertion: Amniocentesis is an effective method to detect genetic
abnormalities in foetus.
Reason: This method can also be used to detect the sex of foetus.

A.If both assertion and reason are true and reason is correct explanation of
assertion

B.If both assertion and reason are true and reason
is not correct explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false.
8.Assertion: Hepatitis – B , Gonorrhea and syphilis are called as STDs.

Reason: These diseases are trtansmitted through sexual contact.

A.If both assertion and reason are true and reason is correct explanation of
assertion

B.If both assertion and reason are true and reason
is not correct explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false.

9.Assertion: Surgical method of contraception prevents gamete formation .
Reason: Castration is a method of contraception.

A.If both assertion and reason are true and reason is correct explanation of
assertion

B.If both assertion and reason are true and reason
is not correct explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false.

10. Assertion: ICSI technique is used for invitro development of embryo.

Reason: In ICSI ,sperm is directly injected to ovum.

A.If both assertion and reason are true and reason is correct explanation of
assertion

B.If both assertion and reason are true and reason
is not correct explanation of assertion
C.If assertion is true but reason is false

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D.If both assertion and reason are false

11.Assertion: Diaphragms are contraceptive devices which are used by males .

Reason: These devices are inserted in the genital track of male.

A.If both assertion and reason are true and reason is correct explanation
of assertion

B.If both assertion and reason are true and
reason is not correct explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false

12. Assertion: Tubectomy is cutting of vas deference.

Reason: Tubectomy prevents the movements of sperm to reach the place of
fertilization.

A.If both assertion and reason are true and reason is correct explanation
of assertion

B.If both assertion and reason are true and
reason is not correct explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false

13. Assertion: Now a days a large number of couples who are unable to produce
children adopt ART .

Reason:ART is an easy way of producing children without any risk to life at
the time of delivery.

A.If both assertion and reason are true and reason is correct explanation
of assertion

B.If both assertion and reason are true and
reason is not correct explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false

14. Assertion:MTP is an intentional termination of pregnancy before full term.

Reason: MTP is done to prevent unwanted pregnancy due to unprotected
intercourse or failure of contraceptives or rapes etc.

A.If both assertion and reason are true and reason is correct explanation
of assertion

B.If both assertion and reason are true and
reason is not correct explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false

15. Assertion: In GIFT,gamets are transferred to fallopian tube .

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Reason:Fallopian tube provides suitable environment for development of
embryo.

A.If both assertion and reason are true and reason is correct explanation
of assertion

B.If both assertion and reason are true and
reason is not correct explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false
16. Assertion: Implants are inserted subdermal for providing a long

term contraception.

Reason: Implants are hormone containing inserted under the skin in upper arm.

A.If both assertion and reason are true and reason is correct explanation
of assertion

B.If both assertion and reason are true and
reason is not correct explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false
17. Assertion: Condom is a tubular latex sheath which is rolled over male copulatory

organ during coitus.

Reason: Barrier methods of contraception prevent STDs as they prevent body
fluids male and female to come in contact.

A.If both assertion and reason are true and reason is correct explanation
of assertion

B.If both assertion and reason are true and
reason is not correct explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false

18. Assertion: Reproductive and Child Healthcare Programmes is for reproduction
related areas.

Reason: It deals with creating awareness among various reproduction related
aspects.

A.If both assertion and reason are true and reason is correct explanation of
assertion

B.If both assertion and reason are true and reason
is not correct explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false
19. Assertion: In tubectomy fallopian tube is cut and tied.

Reason: Vasectomy is the permanent contraception method of males.

A.If both assertion and reason are true and reason is correct explanation of
assertion

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B.If both assertion and reason are true and reason
is not correct explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false

20. Assertion: Amniocentesis is prenatal technique of studying the health of
foetus with the help of X rays.

Reason: Amniocentesis can be easily done in our country.

A.If both assertion and reason are true and reason is correct explanation of
assertion

B.If both assertion and reason are true and reason is not correct
explanation of assertion
C.If assertion is true but reason is false

D.If both assertion and reason are false

Question Numbers Answers
1D
2A
3A
4A
5A
6B
7B
8A
9D
10 A
11 D
12 D
13 C
14 A
15 C
16 A
17 A
18 A
19 B
20 D

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Case Based Questions
1.Read the following paragraph and answer the questions from (i) to (vi)

STD’s are transferred from one person to another person through sexual contacts
.Infections may be transmitted through blood transfusion , breast feeding , sharing of
needles etc. Gonorrhea, syphilis, genital herpes, genital warts, hepatitis-B, AIDS are
some STD’s. Early symptoms of most of these diseases include during sex or
urination, discharge from genital openings, pain in lower abdomen etc. These
diseases are major threat for the health of society that’s why under reproductive
health care program the prevention and cure of these diseases is of prime
consideration .To avoid STD’s one should escape sexual contact with unknown or
multiple partners ,always use condoms.To prevent STD’s and unwanted pregnancy.

1.Which of the following STD’s are not caused by bacteria.?

a. Chlamydia
b. Syphilis
c. Gonorrhea
d. Genital warts

2.Which of the following reduces risk of STD’s

a. Barrier contraceptive method
b. Oral contraceptive method
c. Implants
d. IUD’s

3.STD’s are considered as self invited diseases. One can protect himself/herself from
these diseases by

a. Regular exercise
b. Taking healthy diet
c. Avoiding sex with multiple partners
d. Taking proper medicines

4.Assertion : AIDS is transferred from one to another person by contact of body
fluid..

Reason : One should use condoms always during coitus to prevent AIDS .
a. A and R both are correct and R is the correct explanation of A.
b. A and R both are correct and R is not the correct explanation of A.
c. A if true and R is false.
d. A and R both are false.

5.Which of the following is a venereal disease, caused by a virus, which also gets
transmitted by blood contact?
a. Gonorrhea
b. Syphilis
c. Trichomoniasis
d. Hepatitis B
6.AIDS is caused by HIV. Its transmitted by

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a. Handshake
b. Blood contact
c. Sexual contact
d. Both B & C

2. Read the following and answer the questions from (i) to (ii).
If small doses of progesterone or progesterone- estrogen combination it acts as
an effective contraceptive method and it’s commonly used by females. These
are available in markets in form of pills and taken for 21 days except the days of
menstruation. They inhibit the process of implantation and ovulation and alter
the quality of cervical mucus to stop or retard entry of sperms. A new oral
contraceptive for females is Saheli which contains non – steroidal preparation.
It’s a once a week pill with less side effects and high efficiency. These pills can’t
prevent STDs. These are effective and easy contraceptive methods but they
come with a number of side effects as nausea, bleeding on unexpected bleeding
etc. that’s why consultation of doctor is necessary about the risks of using
contraceptive pills.

1.The hormones present in contraceptive pills are
a. Androgens and adrenalin
b. Progesteron and estrogen
c. hCG and lactin
d. LTH and relaxin

2.Emergency pills are affective if used within …… hours of ………….
a. 72, ovulation
b. 72, coitus
c. 72, menstruation
d. 72, implantation

3.Which of the following is not a side effect of oral pills in females?
a. Increased sex drive
b. Breast tenderness
c. Nausea
d. Abnormal bleeding

4.Contraceptive pills should be taken without consultation of doctors
a. Always
b. Some times
c. Never
d. Depends upon type of pill

5.Which is the odd statement?
a. Oral contraceptives retar the entry of sperms.
b. Contraceptive pills inhibit ovulation and implantation
c. Oral contraceptives with progesterone- estrogen combination can be used by
males also
d. Oral pills can alter the quality of cervical mucus.

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3. A couple married for 5 years is facing problem in bearing a child even if they are
not practicing any birth control method. Upon consultation, doctor advised them an
assisted reproductive technology involving transfer of gametes into oviducts.
Identify the technique adopted by the couple.
a. ZIFT
b. IUI
c. ICSI
d. GIFT

4.A 23 year old man has been diagnosed with a bacterial infection of
reproductive tract .The symptoms appear were burning sensation during
urination, pus-containing discharge and pain around genitalia. His infection has
incubation period of 2-5 days and is curable.
Then what can be the disease the man is suffering from?
a. Chlamydiosis
b. Gonorrhoea
c. Herpes
d. Syphilis

5. Read the following case and answer the question given below:
Over population causes many family problems. Strategies like birth control methods
help to control population explosion. The Natural methods of birth control do not
involve medications or devices to prevent pregnancy but rather these involve
behavioural practices and making observations about menstrual cycle, Then
Which method do you think helps in contraception by temporary absence of sex?
a. Withdrawal method
b. Rhythm method
c. Lactational amenorrhea
d. Coitus interrupts

ANSWER KEY

1. (i) – (d) 1. (ii) – (a) 1. (iii) – (c) 1. (iv) – (b) 1. (v) – (d)
2. (iii) – (a) 2. (iv) – (c) 2. (v) – (c)
2. (i) – (b) 2. (ii) – (b) 5. (b)

3. (d) 4. (b)

CHECK YOUR GRASP

Time: 90 minute Maximum Marks: 30

General Instructions:

i.All questions are compulsory.

ii.The question paper has three sections: Section A- MCQ, Section B -Assertion –
Reason type questions and Section C- Case study base questions. There are 27
questions in the question paper, Section–A has 15 questions of 1 mark each and.
Section–B has 05 questions of 1 mark each and Section–C has 2 questions of 5 marks
each.

iii.There is no overall choice.

Section-A

1.Which fluid is required for the process of amniocentesis?
(a)Chorionic fluid

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(b)Amniotic
(c)Pleural
(d)cerebrospinal

2. Choose the correct statement out of the following
(a) IUDs can be inserted by user.
(b) IUDs can suppress gametogenesis process.
(c) IUDs increase process of phagocytosis in uterus
(d) IUD if inserted can’t be replaced

3. Which out of the following is an STD?
(a) Syphilis
(b) Genital herpes
(c) Gonorrhoea
(d) All of the above

4. Name the surgical sterilization in which a small part of oviduct is removed or
tied up.

(a) Tubectomy
(b) Falloptomy
(c) Vasectomy
(d) Castration

5. ICSI stands for
(a) Internal cytoplasic semen injection
(b) Intra cytoplasmic semen injection
(c) Intra cytoplasmic sperm injection
(d) Intra cell sperm injection

6. Abortion may happen spontaneously also, state if the statement is
(a) True
(b) False
(c) Sometimes it may happen
(d) It never happens.

7. Choose the correct statement
(a) All STDs are fully curable.
(b) In embryo transfer technique embryo is transferred to uterus always.
(c) By surgical methods of contraception gamete formation is prevented.
(d) IUDs are very popular contraceptives in India.

8.Various techniques are available to assist infertile couples still its benefits are
limited what can be the possible reason?

(a) These techniques are available in few centers only.
(b) These are expensive techniques which require special instruments
and specialists.
(c) Various emotional and social issues are related to these techniques.
(d) All of the above.

9.In in vivo fertilization
(a) Embryo is produced by fusion of gametes in test tube

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(b) Embryo development occurs in test tube.
(c) Fusion of gametes occurs within the female.
(d) Any of the above

10. Cervical caps and vaults are used as ……… of conception

(a) Barrier method
(b) Chemical method
(c) Surgical method
(d) Oral method

11. The oldest method of birth control is

(a) Oral pills
(b) IUDs
(c) Tubectomy
(d) Coitus interruptus

12. Name the constituents of combined pill.

(a) progesterone only
(b) estrogen only
(c) Progesterone and estrogen
(d) LH and relaxin
13. Copper releasing IUDs are
(a) Lippes loop, CuT, Multiload 375
(b) Progestaserts, CuT, Multiload 375
(c) Cu T, LNG 20
(d) CuT, Cu , Multiload 375

14.Match the following: Column II

Column I

1. Oral pills (a) Female, Oviduct

2. Tubectomy (b) Acne

3. Adolescents (c) Progesterone and estrogens

4. Vasectomy (d) Coitus interruptus

5. Temporary birth control method (e) Male, vas deferens

(a) 1 – (b), 2- (c), 3- (a), 4- (e), 5-(d)
(b) 1 – (c), 2- (a), 3- (b), 4- (c), 5-(d)
(c) 1 – (e), 2- (b), 3- (a), 4- (c), 5-(d)
(d) 1 – (c), 2- (d), 3- (a), 4- (e), 5-(b)

15. The birth control device not used by women is

(a) Diaphragm

(b) Condoms

(c) Oral pill

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(d) None of above

SECTION B

16. Assertion: Periodic abstinence is a natural method where couples abstain from
coitus.

Reason: Coitus from day 5-10 should be avoided because it’s the time of
ovulation.

(a) Both assertion and reason are true, and reason is correct
explanation of the assertion.

(b) Both assertion and reason are true, but the reason is not the
correct explanation of the assertion.

(c) Assertion is true but reason is false.

(d) Both assertion and reason are false.

17. Assertion: Diaphragms are contraceptive devices which are used by females

Reason: Diaphragms prevent ovulation process in females.

(a)Both assertion and reason are true, and reason is correct explanation of
the assertion.

(b) Both assertion and reason are true, but the reason is not the correct
explanation of the assertion.

(c)Assertion is true but reason is false.

(d)Both assertion and reason are false.

18. Assertion: The oral contraceptive pills alter the ovulatory cycle and suppress
production of ovum.

Reason: These pills are suggested to be used by women for contraception.
(a)Both assertion and reason are true, and reason is correct explanation

of the assertion.

(b)Both assertion and reason are true, but the reason is not the correct
explanation of the assertion.

(c)Assertion is true but reason is false.

(d)Both assertion and reason are false.

19. Assertion: Sterilisation method is used for males only.

Reason: It’s the permanent method of contraception with very good
reversibility.

(a)Both assertion and reason are true, and reason is correct explanation
of the assertion.

(b)Both assertion and reason are true, but the reason is not the correct
explanation of the assertion.

(c)Assertion is true but reason is false.

(d)Both assertion and reason are false.

20. Assertion: All RTIs are STDs but all STDs re not RTIs.

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Reason: Many common STDs are not infection of reproductive tract but
their mode of transmission is sexual contact also.

e. Both assertion and reason are true, and reason is correct
explanation of the assertion.

f. Both assertion and reason are true, but the reason is not the correct
explanation of the assertion.
g. Assertion is true but reason is false.
h. Both assertion and reason are false.

SECTION C
CASE BASE QUESTIONS

21. Manish saw following figure in a book and out of curiosity he read about the
given device and its functions.

1. Which device is shown in given figure?
(a)Condoms
(b) Cervical cap
(c) Cupper T
(d)Inserts

2.How it prevents pregnancy?
(a)By killing ovum

(b)By preventing ovulation
(c) By decreasing sperm motility.
(d) By disturbing menstrual cycle.

3.Above devices are used by
(a)Males
(b)Females
(c)Male or female any
(d) None of above

v. The metal used in above device is

a. Copper
b. Iron
c. Aluminium

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d. Mixed metal

22. At school Rahul saw a poster regarding awareness program on RCH program.

i. Here RCH stands for

a. Reproductive cycle hygiene
b. Reproduction and child health care program
c. Reproductive committee and child health
d. None of the above

ii. How this condition can be attained

a. By decreasing MMR and IMR
b. By increasing MMR and decreasing IMR
c. By decreasing MMR and increasing IMR
d. None of the above

iii. The given program deals with

(a) education of children
(b)reproductive health of women
(c)health of newborn children
(d)Both b and c

iv. Being a biology student what Rahul can do after knowing all this

a. Show interest in sex education for children if reproduction topic is taught
b. Spread awareness about importance of reprodeuctive health.
c. Both of above
d. None of above

ANSWER KEY
Q.NO. ANS Q.NO. ANS Q.NO. ANS Q.NO. ANS Q.NO. ANS

1 B 2 C3 D4 A5 C

6 A 7 D8 D9 C 10 A

11 D 12 C 13 D 14 B 15 D

16 C 17 C 18 A 19 D 20 A

21(i) C 21(ii) C 21(iii) B 21(iv) A 22(i) B

22(ii) A 22(iii) D 22(iv) C

85

CHAPTER-5: Principles of Inheritance and variations

Heredity is the transfer of
character from parents to
their offspring.
These hereditary
characters are present on the chromosomes in the
form of genes. These gene combinations express
characters which may be more similar to one of its
two parents.

Terms Meaning

Locus Address/ location of a gene in a chromosome e.g. T,A.b,d

Gene Structural & functional unit of chromosome.

Allele Allelomorphs= alternative form of a gene e.g. T and t OR A and a
Both alleles of a gene at a locus similar e.g. AA or aa
Homozygous Both alleles of a gene at a locus dissimilar e.g. Aa or Tt
Both alleles of a gene at a locus similar & dominant e.g. AA
Heterozygous
Both alleles of a gene at a locus similar & recessive e.g. aa
Homozygous
Dominant Genetic constituent of an organism
Homozygous Physical appearance
recessive Graphical representation to calculate the probability of all possible
Genotype genotype.
Phenotype
Punnet Square

Why did Mendel selected Garden Pea (Pisum sativum) for his experiment ?

 Pea is a self-pollinated plant & cross pollination is CONTRASTING CHARACTERS

also possible.(bisexual flower)
 Many varieties were available with observable

alternate forms for a trait.
 Short life span.
 Can be easily grown in small place.
 Seeds easy to handle.

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Working method: Mendel’s success was also due to his meticulous planning and method of work –

 He studied only one character at a time.
 He used all available techniques to avoid cross pollination by undesirable pollen grains.
 He applied mathematics and statistics to analyse the results obtained by him.

Mendel’s work and results:
The results obtained by Mendel were studied and on their basis he proposed certain laws known as “Laws
of heredity”. These laws are discussed below:

1) Law of dominance: This law states that when two
contrasting genes for a character come together in an organism,
only one is expressed externally and shows visible effect. It is
called dominant and the other gene of the pair which does not
express and remains hidden is called recessive.
Explanation:

 Characters are controlled by discrete units called factors
(genes).

 Factors occur in pairs.
 In a dissimilar pair of factors one member of the pair

dominates (dominant) the other (recessive).
The law of dominance is used to explain the expression of
only one of the parental characters in a monohybrid cross in
the F 1and the expression of both in the F2. It also explains
the proportion of 3:1 obtained at the F2.

2) Law of segregation or Purity of gametes:
The two alleles received, one from each parent, segregate

independently in gamete
formation, so that each
gamete receives one or
the other with equal
probability. (Can be explained by monohybrid cross).

3) Law of Independent assortment:Two characters determined
by two unlinked genes are recombined at random in gamete
formation, so that they segregate independently of each other,
each according to the first law (note that recombination here is not
used to mean crossing-over in meiosis). (Can be explained by
dihybrid cross)
DIHYBRID CROSS

He crossed homozygous dominant smooth and yellow seeded
(YYRR) with homozygous recessive wrinkled and green seeded
(yyrr) plants. The F1 hybrid was self pollinated and F2 generation
was obtained with the phenotypic ratio of 9:3:3:1 and genotypic
ratio of 1:2:1:2:4:2:1:2:1.

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TEST CROSS:

A cross between F1 hybrid (DD/Dd) and its homozygous
recessive parent (dd) is called Test Cross. This cross is
called test cross because it helps to find out whether the
given dominant phenotype is homozygous(DD) or
heterozygous(Dd)

INCOMPLETE DOMINANCE:

(Snapdragon – Antirhinnum majus)
If neither of the alleles of a character is completely dominant over the
other and the F1 hybrid is intermediate between the two parents, the
phenomenon is called incomplete dominance.

Homozygous red (RR) flowered variety was crossed with white (rr)
flowered variety. F1 offspring had pink flowers (Rr). The phenotypic ratio
and genotypic ratio in F2 generation in case of incomplete dominance
is 1:2:1.

Multiple Allelism / Codominance:
When a gene exists in more than two allelic forms, it shows the phenomenon of multiple allelism.

A well known example is the inheritance of A, B and O blood groups in human being. The gene for blood
group occurs in three allelic forms IA, IB and i. A person carries any two of these alleles. The gene IA
produces glycoprotein (sugar) A and the blood group is A. The gene IB produces glycoprotein B and the
blood group is B. The gene ‘i’ is unable to produce any glycoprotein and so the person homozygous for it ,
has O group blood. The genes IA and IB are dominant over ‘i’. When IA and IB are present together,
both are equally dominant and produce glycoproteins A and B and the blood group is AB. They are called
codominant alleles.

A IAIA / IA IO
B IBIB / IB IO
AB IAIB
O IOIO

DOMINANCE CODOMINANCE INCOMPLETE DOMINANCE
It is a phenomenon in which
It is a phenomenon in which when when two contrasting alleles are It is a phenomenon in which
two contrasting alleles are presenttogether, both of the when two contrasting alleles are
presenttogether, only one expresses alleles express themselves. present together neither of the
itself and is called dominant whereas alleles is dominant over other
the other which does not express Blood group in Human where and the phenotype formedis
itself is called recessive. presence of IA IB expressed as intermediate of the two alleles.
Mendelian inheritance of Pea plant AB Antirhinnum majus where Red
traits and white flower crossed to give
intermediate Pink.

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POLYGENIC INHERITANCE :

 Galton in 1883 suggested that many instances of continuous variation are heritable like height, mental
capabilities.

 The character is determined by more than one geneeach with
the same but cumulative phenotypic effect.

 Quantitative characters like plant height, yield of crops (size,
shape and number of seeds and fruits per plant), intelligence in
human beings and milk yield in animals determined by many
genes in cumulative.

Skin colour determine by 3 genes ( 6 allels)

(i) Few individuals fall into parental categories;

(ii) The expression level of the phenotype is dependent upon the
number of contributive alleles and is hence more quantitative.

Polygenic inheritance also shows by kernel colour in wheat and
inheritance of cob length in maize. It is generally believed that during
evolution there was duplication of chromosome or chromosome parts
thereby leading to multiple copies of the same gene. A large
number of characters are controlled by polygenes in which alleles
contribute additively to a phenotype. This results in polygenic
inheritance.

Pleiotropy is the phenomenon in which a single gene exhibits multiple phenotypic expression. The
pleiotropic gene affects the metabolic pathways, resulting in different phenotypes. For example,
phenylketonuria is caused by mutation in the gene coding the enzyme phenylalanine hydroxylase which
converts Phenyl alanine into tyrosine. Its deficiency results in conversion of Phenyl alanine into Phenyl
pyruvic acid that accumulated in Brain. It results in Mental retardation,
hypopigmentation.

CHROMOSOME THEORY OF INHERITANCE: W Sutton T Boveri
Chromosome theory of inheritance was proposed by Sutton and Boveri
independently in 1902. The two workers found a close similarity between the
transmission of hereditary characters and behavior of chromosomes while
passing from the one generation to the next through agency of
gametes.

SALIENT FEATURES OF CHROMOSOME THEORY:

 Both chromosomes as well as genes occur in
pairs in the somatic or diploid cells.

 A gamete contains only one chromosome of a
type and only one of the two alleles of a
character.

 The paired condition of both chromosomes as
well as Mendelian factors is restored during
fertilization.

LINKAGE AND RECOMBINATION:
Linkage is the phenomenon, where two or more linked
genes are always inherited together and their
recombination frequency in a test cross progeny is less

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than 50%.

A pair of genes may be identified as linked, if their recombination frequency in a test cross progeny is lower
than 50 percent. All the genes present on one chromosome form a linkage group and an organism
possesses as many linkage groups as its haploid number of chromosomes. If the two genes are fully
linked, their recombination frequency will be 0%.

Morgan saw that when the two genes in a dihybrid cross were situated on the same chromosome, the
proportion of parental gene combinations were much higher than the non-parental type. Morgan attributed
this due to physical association or linkage of two genes and coined the term linkage to describe this
physical association of genes on a chromosome and the term recombination to describe the generation of
non-parental gene combinations.

SEX DETERMINATION BY CHROMOSOMES:

Those chromosomes which are involved in the determination of sex
of an individual are called sex chromosomes while the other
chromosomes are called autosomes.x body was discovered by
Henking in 1891.

 Sex chromosome : the chromosomes determine the sex of living.
 Autosomal chromosomes : they determine the characters other
than sex of living.

Name of Living Male Female TYPE
Human XY XX Male Heterogamety
Drosophila XY XX Male Heterogamety
Insect XO XX
Bird ZZ ZW Female Heterogamety
Honey Bee XM (Drone), XM XM (Male) XX Haplodiploidy

PEDIGREE

AUTOSOMAL DOMINANT AUTOSOMAL RECESSIVE X-LINKED

Vertical inheritance seen Horizontal pattern of inheritance Criss Cross inheritance.
(No skipping of generation seen Mothers are carriers and
seen) sons affected.
Male ad females have equal Male ad females have equal Females are least affected,
chance of Inheritence chance of Inheritence. Both males are affected.
parents can be carrier.
Myotonic dystrophy, Phenyl ketonuria, sickle cell Colour Blindness(detected
anemia(Qualitative disorder),
Marfan Syndrome(disorder Thalassemia(Quantitative using ishithara chart),
disorder) Cystica Fibrosis,
of connective tissue) Haemophilia (sex linked

recessive)

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Mendelian Disorder Chromosomal Disorder

1 This disorder is mainly due to This disorder is caused due to absence

alteration or mutation in the single or excess or abnormal arrangement of

gene. one or more chromosomes.

2 This follows Mendel’s principles of This does not follow Mendel’s

inheritance. principles

of inheritance.

3 This may be recessive or dominant in This is always dominant in nature.

nature

4 For example, haemophilia, sickle-cell For example, Turner’s

anaemia.

MENDELIAN DISORDER

Disorder Reason Symptoms
Haemophilia Non stop bleeding, no blood
Sickle Cell Sex linked recessive disease (X). Females are clotting.
Anaemia unaffected carrier. Oxygen carry capacity
Autosomal recessive trait on chromosome 11. reduced.
Phenylketonuria Sickle shape RBC due to replace the glutamic acid
by valine at the sixth position of β-chain of Mental retardation, presence of
Colour haemoglobin. The disease is controlled by a single phenyl pyruvate in urine.
Blindness pair of allele, HbA HbA (normal) ; HbA HbS Unable to differentiate green
(carrier) and HbS HbS (diseased). The patient has and red colour
sickle shaped RBCs with defective
haemoglobin. They are destroyed more rapidly than
normal RBCs.

Autosomal recessive trait on chromosome 12.
Mutation in phenyl alanine hydroxylase enzyme
results in accumulation of phenyl pyruvate.
Sex linked recessive disorder (X).

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Thalassaemia : it is caused by deletion (mutation) in globin chain of haemoglobin. It reduced
or absence the synthesis of globin in excess of others. Excess globins are insoluble &
accumulate in RBC, it precipitate and lysis the RBC, cause anaemia.

Alpha thalassaemia : Involve two gene HBA1 & HBA2 (4 loci) located on 16th chromosomes. Due to
deletion, decrease the synthesis of alpha globin & enhance beta globin. Excess beta globin in adult &
new born babies, unstable the tetramer of globin results in abnormal oxygen carring capacity.

Beta thalassaemia : Involve one gene HBB on chromosome 11. Due to deletion, increase the
synthesis of alpha globin & decrease the beta globin. Excess alpha globin bind to RBC membrane &
damage them results in anaemia.

CHROMOSOMAL DISORDER

Name of Disorder Reason Symptoms
Down’s Syndrome Trisomy of 21 Short statured with small round head, furrowed tongue &
partially open mouth, flat back, broad flat face, slanting eyes,
Chromosome broad palms with palm crease, many loops on finger,
congenital heart disease, physical, psychomotor & mental
Klinefelter’s 47 (XXY) retardation.
Syndrome In male (XXY): tall stature, feminine physique, breast
development (gynaecomastia), female type pubic hair pattern
Turner’s Syndrome 45 (XO) & poor beard development and sterile.
Short stature, rudimentary ovaries (sterile), breast poor
developed lack of secondary sexual characters.

KNOWLEDGE BASED QUESTION

1. Which one of the following is an example of polygenic inheritance?

(a) Skin colour in humans. (b) Flower color in Mirabilis jalapa

(c) Production of male honey bee. (d) Pod shape in garden pea.

2. Test cross involves

(a) Crossing between two genotypes with dominant trait

(b) Crossing between two genotypes with recessive trait

(c) Crossing between two F1 hybrids

(d) Crossing the F1 hybrid with a double recessive genotype.

3. If a colour blind woman marries a normal visioned man, their sons will be

(a) all colour blind (b) all normal visioned

(c) one-half colour blind and one-half normal

(d) three-fourths colour blind and one-fourth normal

4. Study the pedigree chart given below. What does it show?

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(a) Inheritance of a condition like phenylketonuria as an autosomal recessive trait.

(b) The pedigree chart is wrong as this is not possible.

(c) Inheritance of a recessive sex-linked disease like haemophilia.

(d) Inheritance of a sex-linked inborn error of metabolism like phenylketonuria.

5. All genes located on the same chromosome

(a) form different groups depending upon their relative distance

(b) form one linkage group

(c) will not from any linkage groups

(d) form interactive groups that affect the phenotype

6. Conditions of a karyotype 2n + 1, 2n -1 and 2n + 2, 2n - 2 are called

(a) aneuploidy (b) polyploidy

(c) allopolyploidy (d) monosomy

7. Distance between the genes and percentage of recombination shows

(a) a direct relationship (b) an inverse relationship

(c) a parallel relationship (d) no relationship

8. If a plant heterozygous for tallness is selfed, the F2 generation has both tall and dwarf plants.

It proves the principle of

(a) Dominance (b) segregation

(c) Independent assortment (d) incomplete dominance

9. A human female with Turner’s syndrome has

(a) Karyotype 45+X0 (b) an additional chromosome

(c) Trisomy of X chromosomes (d) Male characteristics

10. In sickle cell anaemia glutamic acid is replaced by valine, which one of the following triplets codes

for valine?

(a) GGG (b) AAG

(c) GAA (a) GUG

11. ZZ/ZW type of sex determination is seen in

(a) Platypus (b) snails

(c) Cockroach (d) peacock

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12. A cross between two tall plants resulted in offspring having few dwarf plants. What would be the

genotypes of both the parents?

(a) TT and Tt (b) Tt and Tt

(c) TT and TT (d) Tt and tt

13. In a dihybrid cross, if you get 9:3:3:1 ratio it denotes that

(a) The alleles of two genes are interacting with each other

(b) it is a multigenic inheritance

(c) it is a case of multiple allelism

(d) The alleles of two genes are segregating independently.

14. Which of the following will not result in variations among siblings?

(a) Independent assortment of genes (b) Crossing over

(c) Linkage (d) Mutation

15. What will never be father's blood group if the mother has blood group B and child blood group O?

(a) A (b) B

(c) AB (d) O

16. Occasionally, a single gene may express more than one effect. The phenomenon is called

(a) Multiple allelism (b) mosaicism

(c) Pleiotropy (d) polygeny

17. In a certain taxon of insects some have 17 chromosomes and the others have 18 chromosomes.

The 17 and 18 chromosome bearing organisms are

(a) Males and females, respectively (b) females and males, respectively

(c) All males (d) all females

18. The inheritance pattern of a gene over generations among humans is studied by the pedigree

analysis. Character studied in the pedigree analysis is equivalent to

(a) Quantitative trait (b) Mendelian trait

(c) Polygenic trait (d) maternal trait

19. It is said that Mendel proposed that the factor controlling any character is discrete and

independent. His proposition was based on the

(a) Results of F3 generation of a cross:

(b) Observations that the offspring of a cross made between the plants having two contrasting

characters shows only one character without any blending

(c) Self pollination of F1 offsprings

(d) Cross pollination of F1 generation with recessive parent

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20. Two genes 'A' and 'B' are linked. In a dihybrid cross involving these two genes, the F1

heterozygote is crossed with homozygous recessive parental type (aa bb). What would be ratio of

offspring in the next generation?

(a) 1:1:1:1 (b) 9:3:3:1 (c) 3: 1 (d) 1:1

Q. No. ANSWER Q. No. ANSWER Q. No. ANSWER Q. No. ANSWER

1 a6A 11 D 16 c
a
2d7 A 12 B 17 b
b
3 a8B 13 D 18 d

4 a9A 14 C 19

5 b 10 D 15 C 20

ASSERTION- REASON BASED QUESTIONS [1 mark]

In the following questions a statement of assertion followed by a statement of reason is given.
Choose the correct answer out of the following choices.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion .
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
1. Assertion: The law of independent assortment can be studied through dihybrid cross.

Reason: Only those genes show independent assortment which are linked.
2. Assertion: Mendel successfully conducted his hybridisation experiments.

Reason: Garden pea was an ideal experimental material.
3. Assertion: In a monohybrid cross, only dominant characters exhibit themselves in the F1

generation.
Reason: Dominant trait is expressed only in the heterozygous condition.
4. Assertion: ABO blood group system is a good example of pleiotropic genes.
Reason: In ABO blood group system, when IA and IB alleles are present together, both express
themselves.
5. Assertion: In birds, females are heterogametic and males are homogametic.
Reason: In birds, females have ZW sex chromosomes and males have ZZ sex chromosomes.
6. Assertion: The maximum frequency of recombination that results from crossing over of linked
genes is 50 percent.
Reason: If distance between linked genes is longer, they show higher frequency of crossing over.
7. Assertion: Down's syndrome is caused due to absence of either X or Y sex chromosome
Reason: Such individuals show mental retardation and broad head with characteristic features.
8. Assertion: Sickle cell anemia is an autosome- linked recessive disorder.
Reason: It appears only in human male which can be transferred to their grandson through carrier
daughter.
9. Assertion: Hemophilia never occurs in women.
Reason: Gene for hemophilia is located on X chromosome.
10. Assertion: The genetic complement of an organism is called genotype.
Reason: Genotype is the type of hereditary properties of an organism.
11. Assertion: Human skin colour show polygenic inheritance.
Reason: Each allele of human skin colour gene shows participation and the phenotype is controlled
by many genes.
12. Assertion: The genes on a chromosome are physically linked.
Reason: The number of linkage groups in an organism is equal to their haploid number of
chromosomes.

13. Assertion: Phenylalanine reductase is needed to breakdown the amino acid phenylalanine

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Reason: Phenylketonuria is an inborn error of metabolism.

Q. No. ANSWER - ASSERTION- Q. No. ANSWER - ASSERTION-
REASON BASED QUESTIONS
REASON BASED QUESTIONS
C
1C 8 C

2B 9 A

3C 10 A
B
4D 11
D
5A 12

6B 13

7D

Case-based/Source-based Questions
1. Study the figures given below and answer the questions that follow.

(i) In a dihybrid cross, when would the proportion of parental gene combinations be much
higher than non-parental types, as experimentally shown by Morgan and his group?

(ii) If two genes are located far apart from each other on a chromosome, how the frequency of
recombination will get affected?

(iii) What are 'true breeding lines that are used to study inheritance pattern of traits in plants?

2. Study the flowchart given below and answer the questions that follow.

(i)What is a mutagen? Name a physical factor that can be mutagen.
(ii) What is point mutation? Give one example.

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(iii)Mention two causes of frame-shift mutation.
3. A relevant portion of Beta-chain of haemoglobin of a normal human is given below:

The codon for the sixth amino acid is GAG. The sixth codon GAG mutates to GAA as a result of
mutation 'A' and into GUG as a result of mutation B'. Haemoglobin structure did not change as a
result of mutation 'A' whereas haemoglobin structure changed because of mutation 'B' leading
to sickle shaped RBCs.

(i) Explain giving reasons how mutation ‘B’ could change the haemoglobin structure and not
mutation 'A'.

(iii) Write the genotype of (a) an individual who is carrier of sickle cell anaemia gene but
apparently unaffected, and (b) an individual affected with the disease.

Q. No. ANSWER - Case-based/Source-based Questions
1
2 (i) When the genes are linked.

3 (ii) Frequency of recombination will be higher.

(iii) Plants which have undergone continuous self pollination for several

generations. These are homozygous for traits.

(i) All the physical and chemical factors that induce mutation are called mutagens.

UV radiation and X-rays are physical mutagens.

(ii) Mutation arising due to change in a single base pair of DNA is called point

mutation. Ex - Sickle cell anemia

(iii) Insertion and deletion of three bases or multiples of three bases cause frame-

shift mutation because the reading frame remains unaltered from that point

onwards.

(i) Due to mutation 'A', GAG mutates to GAA. But both GAG and GAA code for

glutamic acid and hence there is no change in RBCs. Whereas GUG formed due to

mutation 'B' codes for valine and so the RBCs become sickle-shaped.

(ii) (a) HbA HbS (b) HbS HbS

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Chapter 6: Molecular Basis of Inheritance

The DNA

DNA (deoxyribonucleic acid) is double helical structure that was cracked by Watson and Crick based
on the X-ray crystallography results. Each strand of a DNA helix is composed of repeating units of
nucleotides. Nucleotide consists of 3 components: ribose or deoxyribose sugar, nitrogenous base
(purines or pyrimidines) and phosphate.

Fig.1. Structure of nucleotide

There are two types of purines- adenine and guanine. Pyrimidines are of three types- thymine,
cytosine, and uracil. All nucleotides are common in DNA and RNA. But uracil is found in RNA and
thymine is present only in DNA. DNA is negatively charged due to the presence of negatively charged
phosphate groups. A nitrogenous base is linked to the pentose sugar through the N-glycosidic linkage.
Two nucleotides are linked through 3'-5' phosphodiester linkage to form a dinucleotide. A polymer
formed in such a manner has a free phosphate group at 5'-end of ribose sugar, which is referred to as
5’-end of polynucleotide chain. The other end of the polymer has a free 3'-OH group of the ribose
sugar. This is referred to as 3'end of the polynucleotide chain. The bonding between sugar and
phosphates forms the backbone of a polynucleotide chain. The nitrogenous bases are linked to sugar
moiety and project from the backbone.

The salient features of the double helix structure of DNA are as follows-

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• Two polynucleotides chains wrap around each other, where the backbone is constituted by
sugar-phosphate, and bases project inside.

• The two DNA chains are antiparallel to each other. It means, if one chain has the polarity 5'-3',
the other has 3'-5'.

• The bases in the two strands are paired through hydrogen bonding forming base pairs. Adenine
forms two hydrogen bonds with thymine whereas cytosine form three hydrogen bond with
guanine.

• The two strands are coiled in right handed pattern.
• The plane of one base pair stacks over the other in double helix. This, in addition to H-bonds,

confers stability of the helical structure.

Packaging of DNA helix
Positively charged basic proteins that surround the DNA is known as histones. Histones are rich in
basic amino acids such as lysine and arginine. Histones are organized to form a unit of eight molecules
called as histone octamer. The DNA is negatively charged and is packaged by wrapping around the
positively charged histone octamer. This forms a structure called nucleosome. A nucleosome typically
contains 200 base pairs of DNA helix. Nucleosomes form the repeating unit of a structure called
chromatin in nucleus. Chromatin is thread-like stained bodies seen in nucleus. The nucleosomes in
chromatin appear as ‘beads-on-string’ structure when viewed under electron microscope (EM). The
beads-on-string structure in chromatin is packaged to form chromatin fibers that are further coiled
and condensed at metaphase stage of cell division to form chromosomes. At higher levels chromatin
packaging requires additional proteins. These proteins are the Non-Histone Chromosomal (NHC)
proteins. In a typical nucleus, loosely packed region of chromatin stains light and are referred to as
euchromatin. The densely chromatin stains dark are called as Heterochromatin. Euchromatin is
said tobe transcriptionally active chromatin, whereas heterochromatin is inactive.

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Fig.2. Packaging of DNA helix

Fig.3. Griffith experiment
DNA as a genetic material
Griffith performed an experiment known as transforming experiment. He used two strains of
Pneumococcus. These two different strains were used to infect the mice. The two strains used were
type III-S (smooth), that contains outer capsule made up of polysaccharide and type II-R (rough)
strain do not contain capsule. The capsule protects the bacteria from the host immune system.
The Griffith experiment is explained below-

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