Mission Examination : सीबीएसई कक्षा 12वीं के छात्र BIOLOGY का माडल पेपर हल कर आंसर की से करें मिलान

SAMPLE PAPER SUBJECT – BIOLOGY

TIME: 90 Mins. CLASS – XII M.M – 35

General Instructions:

1. This question paper contains three sections.

2. Section A has 24 questions. Attempt any 20 questions.

3. Section B contains 24 questions. Attempt any 20 questions.

4. Section C has 12 questions. Attempt any 10 questions.

5. All questions carry equal marks.

6. There is no negative marking.

SECTION – A

Directions: (Q no. 1 – 24): Section A consist of 24 questions. Attempt

any 20 questions from this section. In case more than desirable no. of

questions are attempted, only first 20 will be considered for

evaluation.

1. Choose the correct statement from the following:

a. Cleistogamous flowers always exhibit autogamy.

b. Chasmogamous flowers always exhibit Geitonogamy.

c. Cleistogamous flowers exhibit both autogamy and Geitonogamy.

d. Chasmogamous flowers never exhibit autogamy.

2. Identify A – E in the following diagram:

3. Mega sporangium along with its protective integuments is called:

a. Ovary

b. Ovule

c. Funicle

d. Chalaza.

4. Plants with ovaries having only one or a few ovules are generally

pollinated by:

a. Bees

b. Butterflies

c. Birds

d. Wind

5. Observe the diagram given below depicting the reproductive structure

of Papaver and identify X and Y.

X Y

a. Syncarpous ovary Stigma

b. Stigma Syncarpous ovary

c. Thalamus Apocarpous ovary

d. Apocarpous ovary Thalamus

6. Match the items in column I with those in column II and choose the

correct answer:

Column I

Column II

A. Funicle

1. Small opening of ovule.

B. Integuments

2. Stalk of ovule

C. Chalaza

3. Protective envelopes of ovule.

D. Hilum

4. Junction part of the ovule.

E. Micropyle

5. Basal part of the ovule.

Options:

A B C D E

a. 2 3 5 4 1

b. 1 3 2 4 5

c. 2 3 1 4 5

d. 2 4 5 1 3

e. 3 4 5 1 2

7. There are 20 flowers in one individual plant of Portulacca. In each

microsporangium of every stamen of all the flowers there are 60

microspore mother cells. How many pollen grains are formed from that

plant?

(a) 12,000 (b) 24,000 (c) 96,000 (d)

48,000

8. The immature male germ cell undergoes division to produce sperms by

the process of spermatogenesis. Choose the correct one with reference

to above.

a. Spermatogonia have 46 chromosomes and always undergo meiotic cell

division.

b. Primary spermatocytes divide by mitotic cell division.

c. Secondary spermatocytes have 23 chromosomes and undergo second

meiotic division.

d. Spermatozoa are transformed into spermatids.

9. Match between the following representing parts of the sperm and

their functions and choose the correct option.

Column I

Column II

A. Head

(i) Enzymes

B. Middle piece

(ii) Sperm motility

C. Acrosome

(iii) Energy

D. Tail

(iv) Genetic material.

a. A – (ii), B – (iv), C – (i), D – (iii)

b. A – (iv), B- (iii), C – (i), D – (ii)

c. A – (iv), B- (i), C – (ii), D – (iii)

d. A – (ii), B – (i), C – (iii), D – (iv)

10. Match each function below with the associated part or parts of the

human male reproductive system shown in the figure.

i. Produces sperms.

ii. Conducts the sperm through the penis to the outside of the body

iii. Produces seminal fluid

iv. Connects the epididymis with the urethra.

a. (i) – G, (ii) – E, (iii) – A, C, D, (iv) – B

b. (i) – A, B, (ii) – E, (iii) C, D, (iv) – G

c. (i) – G, (ii) – F, (iii) – A, B, C, (iv) – E

d. (i) – F, (ii) – E, (iii) – A, B, D, (iv) – C

11. The interstitium surrounding the mammalian ovary is/ are:

a. Smooth muscles

b. Membranes

c. Connective tissues

d. None of these.

12. Diaphragms are contraceptive devices used by the females. Choose

the correct option from the statements given below.

i. They are introduced into the uterus.

ii. They are placed to cover the cervical region.

iii. They act as physical barriers for sperm entry.

iv. They act as spermicidal agents.

a. (i) and (ii)

b. (i) and (iii)

c. (ii) and (iii)

d. (iii) and (iv)

13. Assisted reproductive technologies (ART)-

a. Include social awareness programmes to educate people about

reproductive health and diseases.

b. Include research organisation working to produce new and more

effective contraceptives for birth control.

c. Include a number of special techniques which assist infertile

couples to have children.

d. Both b and c

14. Inflammation of the seminiferous tubules could interfere with the

ability to:

(a) make semen alkaline (b) secrete testosterone

(c) produce spermatozoa (d) eliminate urine from the bladder

15. Milk secreted from the cells of alveoli of mammary lobes reaches

nipple through lactiferous duct (L), mammary duct (M), mammary tubule

(T) and mammary ampulla (A) in the following order -

(a) TMAL (b) MTLA (c) MTAL (d) ATML

16. What is the probability of production of dwarf off springs in a

cross between two heterozygous tall pea plants?

a. Zero

b. 50%

c. 25%

d. 100%

17. In the F2 generation of a Mendelian dihybrid cross, the number of

phenotypes and genotypes are-

a. Phenotypes – 4; Genotypes – 16

b. Phenotypes – 9; Genotypes – 4

c. Phenotypes – 4; Genotypes – 8

d. Phenotypes – 4; Genotypes – 9

18. Which of the following are the reasons for Mendel’s success?

i. Usage of pure lines or pure breeding varieties.

ii. Consideration of one character at a time.

iii. Maintenance of the statistical records of experiments.

iv. Knowledge of linkage and incomplete dominance.

a. (i) and (ii)

b. (i), (ii) and (iii).

c. (i) and (iv)

d. (ii), (iii) and (iv)

19. Given pedigree chart depicts the inheritance of attached ear lobes,

an autosomal recessive trait.

Which of the following conclusions drawn is correct?

a. Parents are heterozygous.

b. Parents are homozygous dominant

c. Parents are homozygous recessive

d. None of the above.

20. If both parents are carriers for thalassemia, which is an autosomal

recessive disorder, what are the chances of pregnancy resulting in an

affected child?

a. 25%

b. 100%

c. No chance

d. 50%

21. The net electric charge on DNA and Histones is:

a. Both positive

b. Both negative

c. Negative and positive respectively

d. Zero

22. Refer to the given figure

Select the option which identifies polarity X and Y and DNA sequence

coding for serine (P) and the anticodon for the same amino acid (Q).

X Y P Q

a. 3’ 5’ TCA UCA

b. 5’ 3’ UUG TCA

c. 3’ 5’ UCA TCA

d. 5’ 3’ TCA UCA

23. Negatively regulatory proteins are known as-

a. Repressor

b. Accessory proteins

c. Catalytic proteins

d. Both a and c

24. Consider the following statements:

I. Structural genes produce mRNA when operator gene is turned on by the

inducer.

II. Promoter gene base sequence determines which strand of DNA acts as

a template.

Choose the correct option:

a. Statement I is correct but II is incorrect.

b. Statement I is incorrect but II is correct.

c. Both statements I and II are correct.

d. Both statements I and II are incorrect.

SECTION – B

Directions: (Q .No 25 – 48) Section B consist of 24 questions. Attempt

any 20 questions from this section. In case more than desirable number

of questions are attempted only first 20 will be considered for

evaluation.

Q. 25 to 28 consist of two statements, Assertion (A) and Reason (R).

Answer these questions selecting the appropriate option given below.

(a) Both A and R are correct and R is the correct

explanation of A.

(b) Both A and R are correct and R is not the correct

explanation of A.

(c) A is true but R is false.

(d) Both A and R are false.

25. Assertion – Mendel conducted artificial pollination experiments for

his genetic studies using true breeding pea lines.

Reason – A true breeding line shows the stable trait inheritance and

expression for several generations.

a. If both Assertion and Reason are true and Reason is the correct

explanation of Assertion.

b. If both Assertion and Reason are true and Reason is not the correct

explanation of Assertion.

c. If Assertion is true but Reason is false.

d. If both Assertion and Reason are false

26. Assertion – Generally a woman does not conceive during the

lactation period.

Reason – The hormone prolactin initiates and maintains lactation in a

postpartum woman.

a. If both Assertion and Reason are true and Reason is the correct

explanation of Assertion.

b. If both Assertion and Reason are true and Reason is not the correct

explanation of Assertion.

c. If Assertion is true but Reason is false.

d. If both Assertion and Reason are false.

27. Assertion - tRNA recognises its corresponding codon in mRNA.

Reason - for each codon, there is an individual tRNA.

a. If both Assertion and Reason are true and Reason is the correct

explanation of Assertion.

b. If both Assertion and Reason are true and Reason is not the correct

explanation of Assertion.

c. If Assertion is true but Reason is false.

d. If both Assertion and Reason are false.

28. Assertion – Ubisch bodies are produced by glandular tapetum.

Reason – Ubisch bodies participated in the thickening of exine.

a. If both Assertion and Reason are true and Reason is the correct

explanation of Assertion.

b. If both Assertion and Reason are true and Reason is not the correct

explanation of Assertion.

c. If Assertion is true but Reason is false.

d. If both Assertion and Reason are false.

29. The given figure is of human female reproductive system. Identify the parts labelled as A, B, C and D and select the correct option.

a. A- Oviduct, B- Uterus. C – Ovarian ligament, D – ovary.

b. A – cervix, B- uterus, C – ovary, D – Tumour

c. A – Uterus, B – Uterine cavity, C – Oviducal funnel, D – Ovary.

d. A – Cervix, B- Uterine cavity, C – Fallopian tube, D – ovary.

30. How many meiotic divisions are necessary to produce 100 pollen

grains?

a. 100

b. 50

c. 25

d. 20

31. Which one of the following events is correctly matched with the

time period in the menstrual cycle?

a. Release of egg: 5th day

b. Endometrium regenerates: 5-10 days.

c. Endometrium secretes nutrients for implantation: 11- 18days.

d. Rise in progesterone level: 1-15 days.

32. What would happen if in a gene encoding a polypeptide of 50 amino

acids, 25th (UAC) is mutated to UAA?

a. A polypeptide of 49 amino acids will be formed.

b. A polypeptide of 25 amino acids will be formed.

c. A polypeptide of 24 amino acids will be formed.

d. Two polypeptides of 24 and 25 amino acids will be formed.

33. Read the given statements and select the correct option.

I. Percentage of homozygous dominant individuals obtained by selfing Aa

individual is 25%.

II. Types of genetically different gametes produced by genotype AABbcc

are 2.

III. Phenotypic ratio of monohybrid F2 progeny in case of Mirabilis

jalapa is 3:1.

a. All statements are true.

b. Statements I and II are true but statement III is false.

c. Statements I and III are true but statement II is false.

d. Statements II and III are true but statement I is false.

37. Diaphragms are contraceptive devices used by the females. Choose

the correct option from the statement given below

(i) They are introduced into the uterus

(ii) They are placed to cover the cervical region

(iii) They act as physical barriers for sperm entry

(iv) They act as spermicidal agents

(a) (i) and (ii) (b) (i) and (iii)

(c) (ii) and (iii) (d) (iii) and (iv)

38. Consider the following statements and select the option stating

which ones are True (T) and which ones are false (F).

(i) Emigration is the movement of individuals out of a place or country

(ii) Combined contraceptive pills contain synthetic

progesterone and Estrogen to check

ovulation

(iii) Depo-Provera are Estrogen derivative injections

(iv) The scientific study of human population is called

demography.

(a) T T F T (b) T F T F

(c) T F F T (d) T F T T

39. In a monohybrid cross between two heterozygous individuals,

percentage of pure homozygous individuals obtained in F1 generation

will be:

(a) 25% (b) 50% (c) 75% (d) 100%

40. Monocistronic transcriptional unit codes for

(a) Single polypeptide (b) Double polypeptide

(c) no polypeptide (d) triple polypeptide

41. Refer to the given statements –

(i) Both wind and water pollinated flowers are not very colourful and

do not produce nectar

(ii) Entomophilous flowers are large, colourful, fragrant and rich in

nectar

(iii) Sausage tree has an insect pollinated flower (sausage tree)

(iv) Sxual reproduction in Volvox is isogamous

Which of the above statements is/are incorrect?

(a) (i) only (b) (ii) only (c) (iii) only (d) (i), (ii) and (iii)

44. In four o'clock plants, the gene for red flower colour (R) is

incompletely dominant over the gene for white flower colour (r), hence

the plants heterozygous for flower colour (Rr) have pink flowers. What

will be the ratio of off springs in a cross between red flowers and

pink flowers?

(a) 75% red flowers, 25% pink flowers

(b) All red flowers

(c) 50% red flowers, 50% pink flowers

(d) Red : Pink : white :: 1 : 2 : 1

46. While analysing the DNA of an organism a total number of 5386

nucleotides were found out of which the proportion of different bases

were : Adenine = 29%, Guanine = 17%, Cytosine = 32%, Thymine = 17%

considering the Chargaff's rule it can be concluded that:

(a) It is a double stranded circular DNA (b) It is a single

stranded circular DNA

(c) It is a double stranded linear DNA (d) No conclusion can be drawn

47. Consider the following statements:

I. New DNA strand is synthesized by the addition of nucleotides at –OH

group

II. DNA synthesis occurs in 5'-3' direction.

Choose the correct option:

(a) Statement I is correct, but II is incorrect (b) Statement I is

incorrect, but II is incorrect

(c) Both statements I and II are correct (d) both statements I

and II are incorrect

48. Match Column I with Column II and select the correct option from

the given codes.

Column – I Column – II

A. Sigma factor (i) 5'-3'

B. Capping (ii) initiation

C. Tailing (iii) Termination

D. Coding Factor (iv) 5' end

(v) 3' end

(a) A-(iii), B-(v), C-(iv), D-(ii) (b) A-(ii), B-(iv), C-

(v), D-(iii)

(c) A-(ii), B-(iv), C-(v), D-(i) (d) A-(iii), B-(v), C-

(iv), D-(i)

SECTION – C

Directions: Section C consist of one case followed by 6 questions

linked to this case (Q. No. 49 to 54). Besides this 6 more questions

are given. Attempt any 10 questions in this section. The first

attempted 10 questions would be evaluated.

Case Study-

Mathew Messelson and Franklin Stahl (1958) performed an experiment to

prove that DNA replication was semi conservative and it was shown in

Escherichia coli and subsequently in higher organisms, such as plants

and human cells. Semi conservative replication means that when the

double stranded DNA helix was allowed to replicate, each of the double

stranded helices consisted of one parental strand and the other newly

synthesised strand formed from the template parental strand following

base complementary rule.

49. Messelson and Stahl used the heavy isotope to prove the

semiconservative nature of DNA replication was

a. 15NH4Cl (b) 14NH3Cl2

c. 13NH2Cl3 (d) all of these.

50. Normal DNA can be differentiated from heavy DNA through

centrifugation method using

a. AgCl density gradient

b. CsCl density gradient

c. CaSO4 density gradient

d. KCl density gradient.

51. Similar experiments like Messelson and Stahl was performed by

Taylor in 1958. The experimental organism of Taylor was:

a. Vicia faba

b. Fungi

c. E. coli

d. Protista

52. Radioisotope used by Taylor in his experiment was:

a. Iron

b. Titanium

c. Thymidine

d. Copper.

53. Which of the following phenomena was experimentally proved by

Messelson and Stahl?

a. Transformation

b. Transduction

c. Semi conservative DNA replication

d. Central Dogma.

55. Observe the diagram based on Hershey and Chase

experiment. If DNA with labelled thymidine was added to a medium where

E. coli is growing, what will happen after five minutes of growth?

a. All the DNA strands of parent as well as daughters will show DNA

with labelled Thymidine.

b. Only parental strands will show thymidine labelled DNA.

c. All the strands of daughters will be having labelled thymidine.

d. Half of the daughter strands will have labelled and half strands

without labelled thymidine.

56. The fast block to Polyspermy develops in response to the:

a. Release of factors.

b. Formation of the fertilisation membrane

c. Spreading of fertilisation cone around egg

d. Opening of Sodium gates in the plasma membrane.

58. In regulation of gene expression in prokaryotes:

I. Lactose acts as a suppressor for the gene expression.

II. Tryptophan act as an inducer for the gene expression.

III. Regulatory gene is the one that produces the repressor molecule.

Choose the correct option containing the correct statements.

a. Only I

b. Only II

c. Only III

d. I and II

59. Read the sequence of nucleotides in the given segment of mRNA and

the respective amino acid sequence in the polypeptide chain.

mRNA AUG UUU AUG CCU GUU UCU UAA

Polypeptide Met- Phe- Met- Pro- Val- Ser

Nucleotide sequence of the DNA strand from which this mRNA was

transcribed is:

a. TAC AAA TAC GGA CAA AGA ATT

b. AUG UUU AUG CCU GUU UCU UAA

c. UAC AAA UAC GGA CAA AGA AUU

d. ATG TTT ATG CCT GTT TCT TAA.

60. Refer to the given diagram and select the incorrect option

regarding X, Y and Z.

a. X and Y are haploid cells whereas Z could be a diploid cell.

b. X is derived from meiotic cell division of microspore mother cell

whereas Y is derived from meiotic cell division of mega spore mother

cell.

c. X is derived from the embryo sac of an angiospermous plant whereas Y

is derived from the pollen grain.

d. X and Y together give rise to a diploid structure whereas Y and Z

together give rise to a triploid structure.

Ms. Geetika Bhatnagar

PGT – BIOLOGY

K.L. International School

Meerut.

निष्कर्ष पर पहुंचने से पहले ध्यान से पढ़ें BIOLOGY का प्रश्न पत्र

मेरठ, जागरण संवाददाता। सीबीएसर्ई टर्म-वन परीक्षा में कक्षा 12वीं बायोलाजी का पेपर शनिवार 18 दिसंबर को है। इस परीक्षा की तैयारी के लिए छात्रों के पास करीब डेढ़ महीने का समय शेष है। मेडिकल क्षेत्र में करियर चुनने वाले और नीट की तैयारी कर रहे छात्रों के लिए बायोलाजी का पेपर बेहद महत्वपूर्ण होता है। इसलिए प्रश्नों को बेहद बारीकी से पढऩे का सुझाव दे रहीं हैं केएल इंटरनेशनल स्कूल की पीजीटी बायोलाजी गीतिका भटनागर। उनके अनुसार किसी निष्कर्ष पर पहुंचने से पहले परीक्षार्थी प्रश्नों को ध्यान से पढ़ लें।

प्रश्नपत्र पढ़ते समय ही लगाएं निशान

परीक्षा में रीडिंग टाइम को बढ़ाकर 20 मिनट कर दिया गया है। छात्रों के लिए बेहतर है कि वह इस समय का सदुपयोग करें और प्रश्नपत्र पढऩे के दौैरान ही संभावित उत्तर पर निशान लगा लें। इससे उत्तर भरते समय दोबारा जांच होगी और उत्तर में गलती की संभावना कम रहेगी। उत्तर गलत होने पर अतिरिक्त गोला ओएमआर में मिलेगा लेकिन कोशिश यह करें कि अतिरिक्त गोले का इस्तेमाल न करना पड़े। जिन प्रश्नों के उत्तर ठीक से आते हैं उन्हें ही पहले हल करें। अतिरिक्त प्रश्नों के उत्तर देने की कोशिश न करें।  ओएमआर के मूल्यांकन में निर्धारित प्रश्न संख्या में पहले दिए गए उत्तर को ही शामिल किया जाएगा। संख्या से अतिरिक्त उत्तर सही होने पर भी मूल्यांकन में नहीं आएगा। एनसीर्ईआरटी की किताबों को बेहद बारीकी से पढ़ें। कोई भी टापिक न छोड़ें। गंभीरता से पढ़ें और रिवीजन भी करते रहें।

प्रश्नपत्र के पैटर्न का भी ध्यान रखें

टर्म-वन एग्जाम में बायोलाजी के पेपर में कुल 60 प्रश्न पूछे जाएंगे। इनमें से 50 प्रश्नों के उत्तर छात्रों को देने होंगे। इन 50 प्रश्नों में सेक्शन ए-बी से 20-20 प्रश्न और सेक्शन-सी से 10 प्रश्नों का उत्तर देना है। हर प्रश्न का उत्तर 0.7 अंक का है। हर तरह के डायग्राम का अध्ययन केवल एनसीर्ईआरटी किताब से ही करें। चैप्टर-छह से कैलकुलेटिव प्रश्न हो सकते हैं जिसे छात्र-छात्राओं को ठीक से अभ्यास  करना चाहिए। निगेटिव मार्किंग नहीं है इसलिए सभी प्रश्नों को हल जरूर करें। यदि किसी छात्र ने 50 से ज्यादा प्रश्नों को के उत्तर दे दिए हैं तो पहले 50 उत्तर को ही मूल्यांकन में शामिल किया जाएगा।

सीबीएसई के कक्षा 12 के BIOLOGY के ऊपर दिए माडल पेपर की उत्तर कुंजी यानि आंसर की नीचे दी गई है।