SECOND YEAR HIGHER SECONDARY
EXAMINATION, MARCH 2024
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PART A: BOTANY
I. Answer any 3 questions from 1 to 4. Each carries 1 score. (3 x 1=3)
In grasses the monocot embryo contains single cotyledons named ______
(Plumule, Radicle, Scutellum, Coleorhiza)
(a) Plasmid
(b) Probe
(c) Clone
(d) Vector
II. Answer any 9 questions from 5 to 15. Each carries 2 scores. (9 X 2 = 18)
(a) Identify the cell 'A' and 'B'.
(b) Write the two features of 'A'.
(a) A: Vegetative cell.
B: Generative cell.
(b) It is bigger in size and has abundant food reserve. It possesses a large, irregularly shaped nucleus.
Name: Filiform apparatus.
Function: It guides the entry of the pollen tube into the synergid.
Genetic Engineering: Techniques to alter the chemistry of genetic material (DNA and RNA) to introduce these into host organisms.
Bioprocess Engineering: Maintenance of sterile ambience in chemical engineering processes to enable growth of only the desired microbe/eukaryotic cell.
• Micro-injection: In this method, recombinant DNA is directly injected into the nucleus of an animal cell.
• Biolistics (Gene Gun): Cells are bombarded with high-velocity micro-particles of gold or tungsten coated with DNA; this method is commonly used for plants.
Cow Name: Rosie.
Protein Found: Human alpha-lactalbumin.
| A | B |
|---|---|
| 1. Biopiracy | A. ADA deficiency |
| 2. Gene Therapy | B. Basmati Rice |
| 3. RNA Interference | C. Cry gene |
| 4. Bacillus thuringiensis | D. Meloidogyne incognita |
| A | B |
|---|---|
| 1. Biopiracy | B. Basmati Rice |
| 2. Gene Therapy | A. ADA deficiency |
| 3. RNA Interference | D. Meloidogyne incognita |
| 4. Bacillus thuringiensis | C. Cry gene |
(1) Name the growth curve 'a' & 'b'.
(2) What does 'K' stands for?
(1) a: Exponential growth curve.
b: Logistic growth curve.
(2) Carrying Capacity.
• Loss of unnecessary sense organs.
• Presence of adhesive organs or suckers to cling on to the host.
• Loss of digestive system.
• High reproductive capacity.
(a) Pyramid of energy is always upright, can never be inverted. Justify.
(b) Which are the other two ecological pyramids?
(a) The energy pyramid is always upright because energy is lost as heat at each trophic level, with only about 10% transferred to the next level.
(b) Pyramid of Number and the Pyramid of Biomass.
(Phytoplankton, Man, Fish, Zooplankton)
1หขแต Trophic Level (Producers): Phytoplankton
2โฟแต Trophic Level (Primary Consumers): Zooplankton
3สณแต Trophic Level (Secondary Consumers): Fish
4แตสฐ Trophic Level (Tertiary Consumers): Man
(a) Expand GPP & NPP.
(b) Write the equation relating GPP with NPP.
(a) GPP: Gross Primary Productivity,
NPP: Net Primary Productivity
(b) NPP = GPP - R
III. Answer any 3 questions from 16 to 19. Each carries 3 scores. (3 X 3 = 9)
(1) Label 'a', 'b', 'c' and 'd'.
(2) Name the diploid cell found in embryo sac.
(1) a - Antipodals, b - Polar nuclei, c - Synergids, d – Egg
(2) Central cell (Secondary nucleus/Diploid cell after fusion of polar nuclei).
• Made crops more tolerant to abiotic stresses such as cold, drought, salt, and heat.
• Reduced reliance on chemical pesticides (pest-resistant crops).
• Enhanced nutritional value of food, such as Vitamin ‘A’ enriched rice (Golden rice).
(1) Fill in the blanks a, b, & c in the figure.
(2) Write the name of this process.
(3) What is the name of thermostable DNA polymerase enzyme used in this technique?
(1) a - Denaturation, b - Annealing, c - Extension
(2) PCR (Polymerase Chain Reaction).
(3) Taq polymerase.
(a) Cattle egret and grazing cattle
(b) Fig tree and wasp
(c) Cuscuta growing on hedge plants.
(a) Commensalism — An interaction where one species benefits and the other is neither harmed nor benefited.
(b) Mutualism — An interaction that confers benefits on both the interacting species.
(c) Parasitism — An interaction where one species (parasite) benefits at the expense of the other (host).
PART B: ZOOLOGY
I. Answer any 3 questions from 1 to 5. Each carries 1 score. (3 x 1=3)
II. Answer any 9 questions from 6 to 16. Each carries 2 scores. (9 X 2 = 18)
• Homologous organs: Organs that are similar in anatomical structure and origin but perform different functions (e.g., Forelimbs of whale, bat, cheetah, and human).
• Analogous organs: Organs that are different in anatomical structure but perform similar functions (e.g., Wings of butterfly and birds).
A - Vas deferens
B - Urethra
C - Epididymis
D - Rete testis
(a) Name any two STIs.
(b) Suggest any two methods to prevent STIs.
(a) Gonorrhoea and Syphilis (or Genital herpes, Chlamydiasis, AIDS).
(b) Avoid sex with unknown partners or multiple partners. Always use condoms during coitus.
| Chromosomal Disorder | Karyotype | Symptoms |
|---|---|---|
| A | Trisomy 21 | Palm is broad, Short statured |
| B | C | Gynaecomastia |
| Turner's Syndrome | 44+XO | D |
A - Down's Syndrome
B - Klinefelter's Syndrome
C - 44 + XXY
D - Sterile females with rudimentary ovaries.
• Physical barriers: Skin or mucus coating.
• Physiological barriers: Acid in the stomach, saliva in the mouth.
• Cellular barriers: Leucocytes (WBC) like PMNL-neutrophils and Monocytes.
• Cytokine barriers: Interferons produced by virus-infected cells.
Dryopithecus → A → Australopithecines → B → C → Neanderthal man → D
A - Ramapithecus
B - Homo habilis
C - Homo erectus
D - Homo sapiens
(a) Name two surgical methods advised for male and female partner as a terminal method.
(b) Give two examples for copper releasing IUDs.
(a) Vasectomy (males) and Tubectomy (females).
(b) CuT, Cu7, or Multiload 375.
(a) Name the inheritance pattern.
(b) F1 was self-pollinated and F2 was obtained. What is the genotypic ratio and phenotypic ratio of F2.
(c) Mention a plant which shows this inheritance.
(a) Incomplete dominance.
(b) Phenotypic ratio - 1:2:1, Genotypic ratio - 1:2:1
(c) Snapdragon (Antirrhinum sp.)
A - Transcription, B - Translation
| A | B |
|---|---|
| Clostridium butylicum | Acetic acid |
| Aspergillus niger | Lactic acid |
| Acetobacter aceti | Butyric acid |
| Lactobacillus | Citric acid |
| A | B |
|---|---|
| Clostridium butylicum | Butyric acid |
| Aspergillus niger | Citric acid |
| Acetobacter aceti | Acetic acid |
| Lactobacillus | Lactic acid |
(a) Do you agree with that statement?
(b) Name the clinical test used to diagnose AIDS.
(c) How do HIV infect human body?
(a) No. AIDS spreads through body fluids.
(b) ELISA (Enzyme-Linked Immuno-Sorbent Assay).
(c) HIV enters helper T-lymphocytes (TH), replicates, and produces progeny viruses, decreasing the number of helper T-lymphocytes.
III. Answer any 3 questions from 17 to 20. Each carries 3 scores. (3 X 3 = 9)
(a) Identify 'A' and 'B' in graph.
(b) Identify the structure 'C' and write its function.
(c) Which pituitary hormone is secreted in its maximum level during the time of ovulation?
(a) A - Estrogen, B - Progesterone.
(b) C - Corpus luteum. It secretes progesterone essential for maintaining the endometrium.
(c) LH (Luteinizing Hormone).
• Isolation of DNA.
• Digestion of DNA by restriction endonucleases.
• Separation of DNA fragments by electrophoresis.
• Transferring (blotting) of separated DNA fragments to synthetic membranes.
• Hybridisation using labelled VNTR probe.
• Detection of hybridised DNA fragments by autoradiography.
(a) Which are the four major causes of biodiversity losses?
(b) Name two different methods of biodiversity conservation.
(c) What is so special about tropics that might account for their greater biological diversity?
(a) Habitat loss and fragmentation, Over-exploitation, Alien species invasions, and Co-extinctions.
(b) In-situ conservation (National parks) and Ex-situ conservation (Zoological parks).
(c) Tropics had more evolutionary time, relatively constant environment, and receive more solar energy.
(a) Identify the trait represented as A and B.
(b) Which is the symbol for consanguineous mating used in pedigree analysis?
(c) What do you mean by pedigree analysis?
(a) A - Autosomal dominant trait
B - Autosomal recessive trait.
(b) ▢=◯
(c) The study of the inheritance of a particular trait over several generations within a family tree.