NODIA APP Sample Paper 19 Page 1

RAMSAKHI RAMNIWAS CONVENT SCHOOL

Bharauli, Gorakhpur
Class XII 2024-25
Biology (044)
Time: 3 Hours Max. Marks: 70
General Instructions:
1. All questions are compulsory.
2. The question paper has five sections and 33 questions. All questions are compulsory.
3. Section—A has 16 questions of 1 mark each; Section—B has 5 questions of 2 marks each; Section—C
has 7 questions of 3 marks each: Section—D has 2 case-based questions of 4 marks each; and Section—E
has 3 questions of 5 marks each.
4. There is no overall choice. However, internal choices have been provided in some questions. A student
has to attempt only one of the alternatives in such questions.
5. Wherever necessary, neat and properly labeled diagrams should be drawn.

SECTION - A

Q. No. 1 to 12 are multiple choice questions. Only one of the choices is correct. Select and write the correct
choice as well as the answer to these questions.

1. Egg apparatus consists of

(a) egg cell and two synergids. b) egg cell and central cell.
(c) egg cell and antipodal cells. (d) egg cell and one synergid.

2. Person having genotype IA IB would show the blood group as AB. This is because of
(a) Pleiotropy (b) incomplete dominance
(c) segregation (d) Codominance

3. The given figures (A, B and C) are types of gametes of different organisms. Identify gametes (A, B and
C) respectively.

(a) Heterogametes, isogametes, Homogametes

(b) Homo/Isogametes, heterogametes, heterogametes
(c) Homogametes, isogametes, heterogametes
(d) Isogametes, homogametes, heterogametes

4. The ratio of phenotypes in F2 of a monohybrid cross is

(a) 9 : 3 : 3 : 1 (b) 1 : 2 : 1
(c) 3 : 1 (d) 2 : 1
Page 2 Sample Paper 19 CBSE Biology Class 12

5. The feature of some structures of male reproductive system is given below. Identify the structure on the
basis of the characteristics which surrounds the primary sex organ of male reproductive system.
(a) It is responsible for maintaining the low temperature by about 2 - 2.5° C from normal body temperature
to mature sperm.
(b) It travels through the penis and carry semen as well as urine.
(c) Its enlarged end is called glans penis.
(d) Stores sperms prior to ejaculation.

6. Progestogens in the contraceptive pill

(a) checks attachment of zygote endometrium (b) inhibits estrogen
(c) prevents ovulation (d) All of the above

7. Which of the following crosses will give tall and dwarf pea plants in same proportions?
(a) TT × tt (b) tt × tt
(c) TT × Tt (d) Tt × tt

8. What is meant by the term Darwin fitness?

(a) Healthy appearance (b) High aggressiveness
(c) The ability to survive and reproduce (d) Physical straight

9. Which of the following is a plasmid?

(a) Sal I (b) Barn HI
(c) pBR322 (d) Eco RI

10. The given figures show the members of fungi and simple plants such as algae which undergo asexual
reproduction. Identify the correct asexual reproductive structures found in the members A, B, C and
D.

(a) A-Zoogamete, B-Conidia, C-Bud, D-Gemmule

(b) A-Aplanospore, B-Conidia, C-Bud, D-Gemmule
(c) A-Zoospore, B-Conidiosporangium, C-Bud, D-Gemmule
(d) A-Zoospore, B-Conidia, C-Bud, D-Gemmule

Continue on next page.....

NODIA APP Sample Paper 19 Page 3

11. Amniocentesis technique is used for the

(a) Sex determination of foetus
(b) Determination of any genetic abnormality in the embryo
(c) Determination of errors in amino acid metabolism in embryo.
(d) Both (b) and (c)

12. Dark coloured Peppered Moth is able to survive in industrial areas as compared to light coloured form
because of
(a) Natural selection in smoky environment
(b) Mimicry
(c) High fecundity
(d) Lethal mutation

13. Assertion : Pyramid of energy maybe upright or inverted.

Reason : Only 10% of energy goes to next trophic level.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true and R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is False but R is true.

14. Assertion : UAA, UAG and UGA terminate protein synthesis.

Reason : They are not recognised by tRNA.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true and R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is False but R is true.

15. Assertion : Bt cotton is resistant to insects.

Reason : Butterfly feeding on Bt cotton will die.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true and R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is False but R is true.

16. Assertion : Jave Ape man, Peking man and Heidelberg man are the fossils of Homo erectus.
Reason : Homo erectus evolved from Homo habilis.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true and R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is False but R is true.

Continue on next page.....

Page 4 Sample Paper 19 CBSE Biology Class 12

SECTION-B
17. In the adjacent figure of a typical dicot embryo, label the parts (1), (2) and (3). State the function of each
of the labelled part.

18. How is genetic engineering used in molecular diagnosis of disease ?

19. What does S-shaped pattern of population growth represent ? How is J-shaped pattern different from it
and why ?

O
Explain symbiosis or mutualism by giving one example.

20. In humans, insulin is synthesised as a pro-hormone that needs to be processed before it becomes a fully
mature and functional hormone. How is this challenge for production of insulin using rDNA techniques
overcome for getting insulin assembled into a mature form? Explain the steps using flow chart.

21. What do you mean by gametogenesis ? Describe the structure of a human sperm.

O
Where are the Leydig cell present? What is their role in reproduction?

Continue on next page.....

NODIA APP Sample Paper 19 Page 5

SECTION-C
22. (i) Name any two copper releasing IUDs.
(ii) Explain how do they act as effective contraceptives in human females.

23. Gregor Mendel conducted hybridisation experiments on garden peas and proposed the laws of inheritance
in living organisms. For his experiments, Mendel
(i) conducted artificial pollination experiments using several true-breeding pea lines which were similar
except for one character with contrasting traits.
(ii) applied statistical analysis and mathematical logic to problems in biology
(a) What are true-breeding lines? Explain with the help of an example.
(b) Why did Mendel use true-breeding lines for his hybridisation experiments?
(c) Name one mathematical logic used by Mendel. Which other method can be used for the
same?

24. A person is suffering from ringworm disease. Mention the pathogen. Give the symptoms of the disease
along with the mode of transmission.

25. Observe the diagram of gel electrophoresis and answer the questions which follow:

(i) Name the substance used as a medium/matrix in gel electrophoresis along with its source.
(ii) Why does DNA move towards the anode in gel electrophoresis?
(iii) How one can observe DNA in the gel after electrophoresis?

26. A decade ago, there was abundance of Abingdon tortoise in Galapagos Island but now this species has
become extinct?
(i) Why have they become extinct?
(ii) What can you say about such a relation?


O
Name and describe different hierarchial levels of biological diversity

Continue on next page.....

Page 6 Sample Paper 19 CBSE Biology Class 12

27. The diagram below shows embryo sac after fertilisation. Observe it and answer the following questions.

(i) Give the names of the structures which develop from parts labelled as A and B in the above
diagram.
(ii) How is the structure developed from part ‘13’ different from perisperm?
(iii) Meiocyte of onion has 16 chromosomes. What will be the number of chromosomes in the structures
developing from parts ‘A’ and `13’ ?

28. (i) Francis Crick.

(ii)

Clovel leaf structure of tRNA

(iii) The actual structure of tRNA looks like inverted L.

Continue on next page.....

NODIA APP Sample Paper 19 Page 7

SECTION-D
29. Read the following and answer any four questions from 29 (i) to 29 (iv) given below:
The cytological observations made in a number of insects led to the development of the concept of
genetic/chromosomal basis of sex-determination. Henking (1891) could trace a specific nuclear structure
all through spermatogenesis in a few insects, and it was also observed by him that 50 per cent of the
sperm received this structure after spermatogenesis, whereas the other 50 per cent sperm did not receive
it. Henking gave a name to this structure as the X body but he could not explain its significance.
Further investigations by other scientists led to the conclusion that the ‘X body’ of Henking was in fact
a chromosome and that is why it was given the name X-chromosome. It was also observed that in a large
number of insects the mechanism of sex determination is of the XO type, i.e., all eggs bear an additional
X-chromosome besides the other chromosomes (autosomes). On the other hand, some of the sperms
bear the X-chromosome whereas some do not. Eggs ertilised by sperm having an X-chromosome become
females and, those fertilised by sperms that do not have an X-chromosome become males. Grasshopper is
an example of X0 type of sex determination in which the males have only one X-choromosome besides the
autosomes, whereas females have a pair of X-chromosomes. insects and mammals including man, XY type
of sex determination is seen where both male and female have same number of chromosomes.
Among the males an X-chromosome is present but its counterpart is distinctly smaller and called the
Y-chromosome. Females, however, have a pair of X-chromosomes. Both males and females bear same
number of autosomes. Hence, the males have autosomes plus XY, while female have autosomes plus XX.
In human beings and in Drosophila the males have one X and one Y chromosome, whereas females have a
pair of X chromosomes besides autosomes. males produce two different types of gametes, (a) either with
or without X-chromosome or (b) some gametes with X-chromosome and some with Y-chromosome. Such
types of sex determination mechanism are designated to be the example of male heterogamety. Organisms,
e.g., birds a different mechanism of sex determination is observed. In this case the total number of
chromosome is same in both males and females. But two different types of gametes in terms of the sex
chromosomes are produced by females, i.e., female heterogamety. In order to have a distinction with the
mechanism of sex determination described earlier, the two different sex chromosomes of a female bird has
been designated to be the Z and W chromosomes. In these organisms the females have one Z and one W
chromosome, whereas males have a pair of Z-chromosomes besides the autosomes.
(i) Organism that have XO type of sex-determination?
(ii) What factors determines a human child’s sex?
(iii) Which type of sex chromosome found in female bird?


O
(iv) Name the gametes produces by males?

30. Read the following and answer any four questions from 30 (i) to 30 (iv) given below:
Acquired immunity, on the other hand, is pathogen specific. It is characterised by memory. This means
that our body when it encounters a pathogen for the first time produces a response called primary
response which is of low intensity. Subsequent encounter with the same pathogen elicits a highly intensified
secondary or anamnestic response. This is ascribed to the fact that our body appears to have memory
of the first encounter. The primary and secondary immune responses are carried out with the help of
two special types of lymphocytes present in our blood, i.e., B-lymphocytes and T- lymphocytes. The
B-lymphocytes produce an army of proteins in response to pathogens into our blood to fight with them.
These proteins are called antibodies. The T-cells themselves do not secrete antibodies but help B cells
produce them. Each antibody molecule has four peptide chains, two small called light chains and two
longer called heavy chains. Hence, an antibody is represented as H2L2. Different types of antibodies are
produced in our body. IgA, IgM, IgE, IgG are some of them. Because these antibodies are found in the
blood, the response is also called as humoral immune response. This is one of the two types of our acquired
immune response - antibody mediated. The second type is called cell-mediated immune response or cell-
mediated immunity (CMI). The T-lymphocytes mediate CMI. Grafts from just any source - an animal,
another primate, or any human beings cannot be made since the grafts would be rejected sooner or later.
Page 8 Sample Paper 19 CBSE Biology Class 12

Tissue matching, blood group matching are essential before undertaking any graft/transplant and even
after this the patient has to take immuno-suppresants all his/her life. The body is able to differentiate
‘self’ and ‘non-self and the cell-mediated immune response is responsible for the graft rejection.
(i) What type of response mediated by antibodies?
(ii) Which cell is responsible for cell mediated immunity?
(iii) Which molecules are most responsible for rejection of transplant?
(iv) Which immunoglobulin does constitute the largest percentage in human milk?

SECTION-E
31. Blood samples from a crime scene was collected and DNA analysis for the same was done. Given below
are the marker profiles collected at the crime scene of the victim and a suspect.

(i) What will you conclude on the basis of above observation?

(ii) Discuss how this technique helps in determining that the blood samples picked up from the crime
scene belong to a single person or two different persons.
(iii) How can be the maternal and paternal identity disputes sorted out using the technique used above?


O

(i) Select the homologous structures from the combinations given below :
(a) Forelimbs of whales and bats
(b) Tuber of potato and sweet potato
(c) Eyes of octopus and mammals
(d) Thorns of Bougainvillea and tendrils of Cucurbita.
(ii) State the kind of evolution represent by the homologous structures.
(iii) What are analogous structures? How are they different from homologous structures? Provide one
example for each.

32. Many plant and animal species are on the verge of their extinction because of loss of forest land by
indiscriminate use by the humans.
(i) Why there is a need to conserve biodiversity?
(ii) Mention a method that you would suggest to protect such threatened species from getting extinct.
(iii) Alien species are highly invasive and are a threat to indigenous species. Substantiate this statement
with any two examples.


O
NODIA APP Sample Paper 19 Page 9

Refer the table given below and answer the following questions.
Table : Types of Interaction

Species A Species B Name of Interaction

÷ + P
— — Q
+ — R
+ — S
+ 0 T
— 0 U
(i) Identify P, Q, R, S, T and U.
(ii)
(a) An orchid growing as an epiphyte on a mango branch is an example of which interaction?
(b) Name the type of interaction seen between wasp and fig tree.
(iii) Give one example of interaction ‘P’.

33. DNA is a hydrophilic molecule so it cannot pass through cell membranes. In order to force host bacteria
to take up the plasmid, the bacterial cells must first be made ‘competent’. How are bacterial cells made
competent? Summarise the steps that are performed to introduce alien DNA into competent bacterial
cells? How can alien DNA be introduced into plant and animal host cells?


O
Given below is the schematic diagram of a cloning vector pBR322. Observe the diagram and answer the
following questions.

(i) Write the term for segment C of the vector. Why is it important?
(ii) Segments A and B of the vector have restriction sites for many endonucleases, each of which is
represented by letters followed by Roman numeral. Explain the naming of any one restriction
enzyme.
(iii) A foreign DNA has been inserted in the segment B. How one can identify E. coli cells with
recombinant plasmids from cells with no plasmid or with non-recombinant plasmids?

******