Biology (Class 12) Term 2 Question Paper 2023
SECTION-A
1. At which stage during evolution did human use hides to protect their bodies 1 and buried their dead?
(a) Homo habilis
(b) Neanderthal man
(c) Java man
(d) Homo erectus
2. Given below are Column A with a list of certain Assisted Reproductive 2. Technologies (ART) and in Column B the procedures followed during ART:
| Column A | Column B | ||
| S. No. | Names of ART | S. No. | Procedures |
| (A) | GIFT | (i) | Transfer of ovum from a donor into the (A) GIFT fallopian tube of another female. |
| (B) | ICSI | (ii) | Transfer of semen from the donor into the vagina of the female. |
| (C) | ZIFT | (iii) | Injecting sperms directly into the ovum. |
| (D) | IUI | (iv) | Transfer of early embryos into the fallopian tube. |
Choose the option where ART correctly matches with the procedure.
| (a) | (A)- (i), | (B)-(i), | (C)-(iii), | (D)- (iv) |
| (b) | (A)- (iv), | (B)- (i), | (C)- (ii), | (D)- (iii) |
| (c) | (A)- (iv), | (B)- (ii), | (C)- (i), | (D)- (ii) |
| (d) | (A)- (i), | (B)- (ii), | (C)- (iv), | (D)- (ii) |
3. The decrease in the T lymphocytes count in human blood will result in:
(a) Decrease in antigens
(b) Decrease in antibodies
(c) Increase in antibodies
(d) Increase in antigens
8. Given below is the restriction site of a restriction endonuclease Pst-I and the cleavage sites on a DNA molecule.
5’C-T-G-C-A G 3′
3′ G A-C-G-T-c5
Choose the option that gives the correct resultant fragments by the action of the enzyme Pst-I.
9. The IUCN Red Data List (2004) in the last 500 years documents the 9. 1 extinction of nearly 784 species including:
(a) 330 invertebrates
(b) 338 invertebrates 14
(c) 359 invertebrates
(d) 362 invertebrates
10. Given below are the list of the commercially important products and their source organisms. Select the option that gives the correct matches.
| List A | List B | ||
| S. No. | Bioactive Products | S. No. | Microbes (Source Organism) |
| (A) | Cyclosporin A | (i) | Streptococcus |
| (B) | Statins | (ii) | Tricoderma polysporum |
| (C) | Streptokinase | (iii) | Penicillium notatum |
| (D) | Penicillin | (iv) | MonascuS purpureus |
Options:
| (A)-(i), | (B)-(ii), | (C)-(iii), | (D)-(iv) | |
| (A)-(iii), | (B)-(iv), | (C)- (ii), | (D)-(i) | |
| (A)-(iv), | (B)-(iii), | (C)-(ii), | (D)-(i) | |
| (A)-(ii), | (B)-(iv), | (C)- (i), | (D)-(iii) |
11. Important attributes belonging to a population but not to an individual are:
(i) Birth rate and death rate
(ii) Male and female
(iii) Birth and death
(iv) Sex-ratio
Select the correct option from the given options:
(a) (i) only
(b) (ii) only
(c) (i) and (ii)
(d) (i) and (iv)
12. Select the option that shows the correctly identified U’, X, Y and Z’ in a 1 developing dicot embryo.
(a) X Plumule (2n), Y Suspensor (n), Z Cotyledon (2n), U Radicle (2n).
(b) X Plumule (2n), Y Suspensor (2n), Z Radicle (2n), U Cotyledon (2n).
(c) X Suspensor (2n), Y -Cotyledon (2n), Z Radicle (2n), U Plumule (2n).
(d) X-Cotyledon (2n), Y -Radicle (n), Z-Plumule (n), U Suspensor (n).
Question Nos. 13 to 16 consists of two statements, Assertion (A) and reaso (R). Answer these questions selecting the appropriate option given below
(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 the correct explanation ot (A)
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.
13. Assertion (A) : Determining the sex of an unborn child followed by MTP is an illegal practice.
Reason (R): Amniocentesis is a practice to test the presence of genetic disorders also.
14. Assertion (A) : Synthetic oligonucleotide polymers are used during Annealing in a PCR. Reason
(R): The primers bind to the double stranded DNA at their 1 complementary regions.
15. Assertion (A) : Decomposition process is slower if detritus is rich in lignin and cutin. 1 Reason (R) : Decomposition is largely an oxygen requiring process.
16. Assertion (A) : In Thalassemia an abnormal myoglobin chain is synthesized due to a gene defect.
Reason (R) : a-Thalassemia is controlled by genes HBA1 and HBA2 on chromosomé 16.
SECTION -B
17. The graph given below shows the numher of nrimordial follicles per ovary 17. women at ditterent ages. Study the graph and answer the questo follow.
(a) What is the average age of the women at the onset of menopause?
(b) At what age are maximum primordial follicles present in the ovary, according to the given graph ?
18. “Cattle and goats do not browse the Calotropis plant.” Justify the statement giving reasons.
19. By using Punnett square depict the genotypes and phenotypes of test crosses (where green pod colour (G) is dominant over yellow pod colour (g)) in Garden pea with unknown genotype.
20. (a) (i) Give an example of a genus of virus used as narrow spectrum insecticidal biocontrol agent.
(ii) How does its use serve as an aid in overall integrated pest 2 r management programme?
OR
b) Why a malignant tumour considered to be more damaging than a 2 benign tumour? Explain.
21. (a) Write the scientific name of the source organism of the thermostabie DNA polymerase used in PCR.
(b) State the advantage of using Thermostable DNA polymerase.
SECTION -C
22. Name and explain a surgical contraceptive method that can be adopted by. the male partner of a couple.
23. Human Genome Project (HGP) was a mega project launched in the year 1990 23 with some important goals.
(a) Enlist any four prime goals of HGP.
(b) Name any one common non-human animal model organism which has also been sequenced thereafter.
24. Industrial melanism in England after 1850 is an excellent example of Natural selection. Explain how?
25. One of the major approaches of crop improvement programme is Artificial 25. Hybridisation. Explain the steps involved in making sure that only the desired pollen grain pollinate the stigma of a bisexual tlower by a plant 3 breeder.
26. (a) “Plasmodium protozoan needs both a mosquito and a human host for its continuity.” Explain.
OR
(b) We all must work towards maintaining sood health beeause ‘health is wealth’. Enlist any six ways of achieving good health.
27. On apraying Bacillus thuringienas on an infected cotton crop field the pesta are killed by the toxin, however the toxin although produced by the bactera does not affect it. Explain giving reason.
28. “Biodiversity plays a major role in many ecosystem services that nature provides.”
(a) Describe any two broadly utilatarian arguments to justify the given statement.
(b) State one ethical reason of conserving biodiversity.
SECTION-D
Q. Nos. 29 and 80 are case based questions. Each question has subparta with internal choice in one subpart.
29. When a microorganism invades a host, a definite sequence of events usually occur leading to infection and disease, causing suffering to the host. This process is called pathogenesis. Once a microorganism overcomes the defense system of the host, development of the disease follows a certain sequence of events as shown in the graph. Study the graph given below for the sequence of events leading to appearance of a disease and answer the questions that follow :
