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CBSE 12th Standard Biology Sexual Reproduction in Flowering Plants Sample Question Papers Study Material - QB365

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Questions:

Generic 2

5 x 2 = 10

Give a scientific term for the following sentences.
(i) A surgical procedure performed on males in which the vas deferens are cut and tied is known as .....
(ii) A contraceptive device consisting of a small thimble-shaped cup that is placed over the uterus to prevent the entrance of spermatozoa ..........
(ii) Voluntary termination of pregnancy before its full term.

A mother gives birth to a baby. Soon after delivery, the mother-in-law insists of giving water and honey to the new born. But the father of the baby opposed this decision and took the baby to the mother of the newborn, so that the baby gets the first milk.
a) What is the milk called which comes out of the mammary gland of the mother during the initial days of lactation? What is its significance?
b) What value can you find in the father of the baby?
c) Name the hormones which influence lactation.

Lable the following.

Mention the names and the characteristics of different uterine wall layers in humans.Which one of them undergoes cyclic changes during menstrual cycle?

Geitonogamous flowering plants are genetically autogamous, but functionally cross-pollinated. Justify.

Generic 3

7 x 3 = 21

A couple where both husband and wife are producing functional gametes, but the wife is still unable to conceive, is seeking medical aid.
Describe any one method that you can suggest to this couple to become happy parents.

In the diagram given below, identify the parts of the flower and mention the post-fertilisation changes shown in the parts

Given reasons for the following statements:
(a) Parturition is also termed labour.
(b) Early secretions from mammary glands of mother are very useful to newly born baby.
(c) Testes in males are lodged in the scrotum so as lie outside the abdominal cavity.

Which one of the following is responsible for nourishment to the developing embryo? Answer giving reasons.

10.

A little child girl, Ruchika of five years had curiosity, asked her mother.Why did not she possess the moustaches and beard like her daddy.
(i) Name the hormone responsible for the development of moustaches and beard.
(ii) Name the cells and their location which secrete this hormone.
(iii) Name the cells and their location which secrete the hormone responsible for the development of female characteristics in a female.Are there additional structures in the female reproductive system which secrete hormones? Name them.

11.

(a) Mention the exact location or the site in a flowering plant, where the following developments take place:
(i) Deposition of sporopollenin
(ii) Triple fusion
(iii) Release of male gametes
(iv) Megasporogenesis.
(b) Draw a labelled diagram of a male gametophyte of an angiosperm.

12.

What is tubectomy?Represent it diagramatically

Generic 5

3 x 5 = 15

13.

In case of polyembryony, if one embryo develops from the synergid and another from the nucellus, which one is haploid and which is diploid? Describe polyembryony and also mention how can it be commercially exploited.

14.

The graph given below shows the variation in the levels of ovarian hormones during various phases of menstrual cycle :

(a) Identify 'A' and 'B'.
(b) Specify the source of the hormone marked in the diagram.
(c) Reason: out why A peaks before B.
(d) Compare the role of A and B.
(e) Under which condition will the level of B continue to remain high on the 28th day?

15.

Discuss the mode of action and advantages/disadvantages of hormonal contraceptives.

Multiple Choice Question

12 x 1 = 12

16.

The disease in which painful ulcers are formed on external genitalia and perianal region is

(a)

Genital warts

(b)

Syphilis

(c)

Genital herpes

(d)

Gonorrhoea

17.

RCH stands for

(a)

routine check up for health

(b)

reproduction cum hygrine

(c)

reversible contraceptive threads

(d)

reproductive and child health care

18.

Identify the correct statement(s) from the following
I) A single female gamete is formed in the female gametophyte of an angiosperm
II) A single female gametophyte is formed in the ovule of an angiosperm
III) A single ovule may be forined in the ovary of an angiosperm
IV) Seven haploid cells are formed in the polygonum type of embryosac of an angiosperm

(a)

I, II only

(b)

II, II only

(c)

I, II, III & IV

(d)

IV only.

19.

Choose the correct labellings for the parts X, Y and Z in the given figure of the stages in embryo development in a dicot.

(a)

X is suspensor, Y is radicle and Z is cotyledon

(b)

X is radicle, Y is cotyledon and Z is suspensor

(c)

X is cotyledon, Y is suspensor and Z is radicle

(d)

X is zygote, Y is radicle and Z is cotyledon

20.

Identify the disease which is not a sexually transmitted disease.

(a)

Gonorrhoea

(b)

Syphilis

(c)

Amoebiasis

(d)

Chlamydiasis

21.

In the human female, menstruation can be deferred by the administration of

(a)

Combination of FSH and LH

(b)

Combination of estrogen and progesterone

(c)

FSH only

(d)

LH only

22.

Which one of the following is the most likely root cause why menstruation is not taking place in the regularly cycling human female?

(a)

retention of well-developed corpus luteum

(b)

fertilization of the ovum

(c)

maintenance of the hypertrophical endometrial lining

(d)

maintenance of high conc. of sex hormones in the blood stream

23.

Foetal ejection reflex in human female is induced by

(a)

differentiation of mammary glands

(b)

the pressure exerted by amniotic fluid

(c)

the release of oxytocin from pituitary

(d)

fully developed foetus and placenta

24.

What is the figure given below showing in particular?

(a)

Ovarian cancer

(b)

Uterine cancer

(c)

Tubectomy

(d)

Vasectomy

25.

Anthesis is a phenomenon which refers to

(a)

Formation of pollen

(b)

Development of anther

(c)

the opening of a flower bud

(d)

Reception of pollen by stigma

26.

In a flowering plant, archesporium gives rise to

(a)

only the wall of the sporangium

(b)

both wall and the sporogenous cells

(c)

wall and the tapetum

(d)

Only tapetum and sporogenous cells

27.

In angiosperms, pollen tubes liberate their male gametes into the

(a)

Central cell

(b)

Antipodal cell

(c)

Egg cell

(d)

Synergids

Case Study Questions

2 x 4 = 8

28.

Oral administration of small doses of either progestogens or progestogen-estrogen combinations is another contraceptive method used by the females. They are used in the form of tablets and hence are popularly called the pills. Pills have to be taken daily for a period of 21 days starting preferably within the first five days of menstrual cycle. After a gap of 7 days during which menstruation occurs, it has to be repeated in the same pattern till the female desires to prevent conception. They inhibit ovulation and implantation as well as alter the quality of cervical mucus to prevent/ retard entry of sperms. Pills are very effective with lesser side effects and are well accepted by the females. Saheli the new oral contraceptive for the females contains a non-steroidal preparation called centchroman. It is a 'once a week' pill with very few side effects and high contraceptive value.
1.The present population of the world is estimated to be
A) 500 million
B) 100 billion
C) 8 billion
D) 15 trillion
2. "Saheli", a new oral contraceptive for the female was developed by scientists at
A) CDRI, Lucknow
B) IISc. Bangalore
C) CSIR, New Delhi
D) ICMR, New Delhi
3.Oral contraceptive pill is composed of
A) estrogen and progesterone
B) estrogen and testosterone
C) progesterone and testosterone
D) estrogen and growth hormone
4.Oral contraceptives are prescribed in females to check :
A) Ovulation
B) Fertilization
C) Implantation
D) Entry of sperms in vagina

29.

(a) Name the human embryonic stage shown above.
(b) Identify 'a' and 'b' in it.
(c) Where are stem cells located in it?
(d) Mention the role of 'b'.

Assertion and reason

4 x 1 = 4

30.

Assertion (A): Hepatitis Bis als0 considered a sexually transmítted dísease.
Reason (R) :It can be spread through sexual contact
Codes:
A) Both (A) and (R) are true and (R) is the correctexplanation of (A)
B) Both (A) and (R) are true and (R) is not thecorrect explanation of (A)
C) (A) is true but (R)is false
D) (A) is false but (R) is true

31.

Assertion (A) Lactational amenorrhea is the natural method of contraception.
Reason (R) It increases the phagocytosis of sperm.
(a) If both A and R are true and R is the correct explanation of the A
(b) If both A and R are true, but R is not the correct explanation of the A
(c) If A is true, but R is false.
(d) If A is false, but R is true

32.

Assertion: In mammals the female secondary sexual characters are developed by gonadotropins.
Reason: Gonadotropins are secreted by Graafian follicle.
(a) Both assertion and reason are true and reason is the correct explanation of assertion.
(b) Both assertion and reason are true but reason is not the correct explanation of assertion.
(c) Assertion is true butreason is false.
(d) Both assertion and reason are false.

33.

Assertion: Perisperm is protective covering of seed and helps in dispersal and nutrition.
Reason: Pericarp is covering of fruit which is non-functional.
Codes :
(a) Both assertion and reason are true and reason is the correct explanation of assertion
(b) Both assertion and reason are true but reason is not the correct explanation of assertion
(c) Assertion is true but reason is false
(d) Both assertion and reason are false

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Answers Key:

Generic 2

5 x 2 = 10

(i) vasectomy
(ii) cervical cap
(ii) Medical Termination of Pregnoncy (MTP)

a) Colostrum. It contains several antibodies needed to develop resistance in the newborn.
b) The father is well informed, aware and caring.
c) Prolactin, oxytocin and progesterone.

The external thin membranous,perimetrium.
The middle,thick layer of smooth muscles,myometrium.
The inner glandular layer lining the uterine cavity,endometrium.Endometrium undergoes cyclic changes.

1. Since geitonogamy involves two different flowers of the same plant, it is genetically similar to autogamy; both autogamy and geitonogamy do not result in genetic variation in the progeny.
2. Geitonogamy and cross-pollination involve different flowers and a pollinating agent.

Generic 3

7 x 3 = 21

Suggested methods for this couple include IVF, ZIFT, and AI.

Parts	Post-fertilisation change
A-Stigma B-Style	Both degenerate
C-Ovary	Fruit
D-Ovule	Seed
E-Integuments	Seed coat

(a) Parturition (childbirth) involves a very hard muscular work at the expense of considerable energy by the mother. It is, therefore, also called labour.
(b) Early secretions from the mammary glands of mother are termed as colostrum. It brings antibodies from mother to combat infections in the newly born baby who till has to build up its own antibodies.
(c) In males, testes are lodged in the scrotum and lie outside the abdominal cavity because the temperature in the scrotum is about 2⁰C lower than that in the abdominal cavity. It is ideal for the development and survival of spermatozoa.

The part responsible for supplying nourishment to the developing embryo is (B) Endosperm because embryo development occurs in the endosperm which is specially meant food to the developing embryo. Cotyledons are the parts of mature embryo which supply food during seed germination.

10.

(i) Androgens, mainly testosterone, secreted by testes and adrenal gland.
(ii) Interstitial cells or Leydig cells, present in the interstitial spaces between the seminiferous tubules.
(iii) Estrogens secreted by ovary.Progesterone hormone is secreted by corpus luteum of ovary and placenta during pregnancy.

11.

(a) (i) On the exine of pollen grains while in the microsporangia.
(ii) In the central cell of embryo sac of the ovule.
(iii) From the pollen sacs.
(iv) In the ovule.

12.

Tubectomy is the sterilisation procedure in females involving ligation of fallopian tube.

Generic 5

3 x 5 = 15

13.

1.Embryo developed from the synergid is haploid as the ploidy level of the synergid is haploid.
2.Embryo developed from the nucellus is diploid as the ploidy of the nucellus is diploid.
3.Presence of more than one embryo in a seed is called polyembryony, e.g. lemon, groundnut, etc.
4.Polyembryony plays an important role in plant breeding and horticulture. The plantlets obtained from these embryos are virus-free and have more vigour. Hybrid varieties of several food and vegetable crops are being extensively cultivated and these hybrid cultivars possess high productivity.

14.

(a) (A) Estrogen
(B) Progesterone
(b) (A) Maturing ovarian follicle/Graafian follicle
(B) Corpus luteum
(c) Formation of Graaffian follicle (releases estrogen) is followed by the formation of corpus luteum (releases progesterone)
(d) Role of A (Estrogen)-Leads to changes in the ovary and uterus/regeneration of endometrium through proliferation
Role of B (Progesterone)-Maintenance of endometrium for implantation of the fertilized ovum/maintenance of other events of pregnancy.
(e) In case of pregnancy.

15.

(i) Mode of Action.   Oestrogen inhibits ovulation by preventing FSH production.
(ii) Advantages.   Hormonal contraceptives are super devices to prevent conception.
(iii) Disadvantages.   They disturb the menstrual cycles.

Multiple Choice Question

12 x 1 = 12

16.

17.

(d)
reproductive and child health care

18.

19.

20.

21.

(b)
Combination of estrogen and progesterone

22.

(d)
maintenance of high conc. of sex hormones in the blood stream

23.

(d)
fully developed foetus and placenta

24.

25.

26.

(b)
both wall and the sporogenous cells

27.

(d)
Synergids

Case Study Questions

2 x 4 = 8

28.

1.C) 8 billion
2.A) CDRI, Lucknow
3.A) estrogen and progesterone
4.A) Ovulation

29.

(a) It is a blastocyst.
(b) 'a' is inner cell mass.
'b' is trophoblast.
(c) Stem cells are present in the inner cell mass.
(d) Role of Trophoblast.
(i) It becomes attached to the endometrium for implantation.
(ii) The chorionic villi appearing on it form the foetal part of placenta.

Assertion and reason

4 x 1 = 4

30.

A) Both (A) and (R) are true and (R) is the correctexplanation of (A)

31.

32.

(d): The female secondary sexual characters are developed by estrogen. Estrogens are steroid hormones secreted by growing ovarian follicles. This hormone is responsible for the development of female secondary sexual and accessory characters. In humans, it is also formed in the adrenal cortex, testis and fetoplacental unit.
Gonadotrophic hormones (LH and FSH) are secreted by the anterior lobe of pituitary gland. LH is responsible for ovulation and transforms Graafian follicle into corpus luteum and FSH stimulates spermatogenesis, maturation of Graafian follicle and secretion of estrogen in ovaries.

33.

(d) Perisperm is unused nucellus in the seed. It is often non-functional for seed. Pericarp is the covering of fruit that develops from ovary wall. It is protective covering and also helps in dispersal and nutrition.