| gyanpankh.com/ |
| CBSE Class 11 Biology Half Yearly |
| Sample Paper |
| CLASS – XI Year: 2025-2026 |
| SUBJECT – Biology (044) |
General Instructions: CBSE Class 11 Biology Half Yearly Paper
Please read the following instructions very carefully and strictly follow them: CBSE Class 11 Biology Half Yearly Paper
(i) This question paper contains 33 questions. All questions are compulsory.CBSE Class 11 Biology Half Yearly Paper
(ii) The question paper is divided into five sections – Sections A, B, C, D, and E. CBSE Class 11 Biology Half Yearly Paper
(iii) Section A – questions number 1 to 12 are multiple-choice type questions. Each question carries 1 mark. For Questions number 13 to 16, two statements are given – one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer from the codes (A), (B), (C), and (D) as given below.
(iv) Section B – questions number 17 to 21 are very short answer-type questions. Each question carries 2 marks. CBSE Class 11 Biology Half Yearly Paper
(v) Section C – questions number 22 to 28 are short-answer type questions. Each question carries 3 marks. CBSE Class 11 Biology Half Yearly Paper
(vi) Section D – questions number 29 and 30 are case-based questions. Each question carries 4 marks. CBSE Class 11 Biology Half Yearly Paper
(vii) Section E – questions number 31 to 33 are long-answer type questions. Each question carries 5 marks. CBSE Class 11 Biology Half Yearly Paper
Section A
This section comprises 12 Multiple Choice Questions (MCQs) of 1 mark each. 12x 1=12
1. A taxonomist intends to assign a scientific name to a newly discovered organism, ensuring global recognition. The most appropriate system for this purpose would be:
| A. Polynomial Nomenclature | B. Binomial Nomenclature | C. Vernacular Naming | D. Hierarchical Classification |
2. In a water sample, an organism is observed that shows characteristics of both plants and animals. This organism most likely belongs to the group:
| A. Protista | B. Monera | C. Fungi | D. Plantae |
3. A plant specimen is observed to have a life cycle showing a dominant, independent gametophyte stage. The plant group it represents is:
| A. Gymnosperms | B. Angiosperms | C. Bryophytes | D. Pteridophytes |
4. The presence of a notochord at some stage of life classifies an animal into the phylum:
| A. Porifera | B. Cnidaria | C. Chordata | D. Echinodermata |
5. A student observes the floral formula ⚥ K(5) C(5) A5 G(2). The nature of the ovary in this flower is:
| A. Superior | B. Half-inferior | C. Inferior | D. Cannot be determined |
6. The tissue responsible for the increase in girth of a dicot stem is identified as:
| A. Apical Meristem | B. Intercalary Meristem | C. Lateral Meristem | D. Parenchyma |
7. In the dissection of an earthworm, the excretory units observed segmentally would be:
| A. Flame Cells | B. Nephridia | C. Malpighian Tubules | D. Kidneys |
8. The organelle primarily involved in packaging materials for transport inside and outside the cell is the:
| A. Endoplasmic Reticulum | B. Lysosome | C. Golgi Apparatus | D. Mitochondria |
9. A biomolecule, upon analysis, is found to be a long-chain polymer of amino acids. This molecule functions primarily as:
| A. An energy source | B. A genetic material | C. A structural component and catalyst | D. A storage product |
10. The phase of the cell cycle where DNA replication occurs is:
| A. G1 phase | B. S phase | C. G2 phase | D. M phase |
11. A cell is observed to have a well-defined nucleus and membrane-bound organelles. Its category is:
| A. Prokaryotic Cell | B. Eukaryotic Cell | C. Virus | D. Bacteriophage |
12. The most abundant chemical in the animal body, serving as the universal solvent, is:
| A. Protein | B. Lipid | C. Water | D. Carbohydrate |
Assertion-Reason based
For Questions 13 to 16, two statements are given – one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer from the codes (A), (B), (C) and (D) as given below. CBSE Class 11 Biology Half Yearly Paper
(A) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of the Assertion (A).
(B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
(C) Assertion (A) is true, but Reason (R) is false.
(D) Assertion (A) is false, but Reason (R) is true.
13. Assertion (A): The cell wall of fungi is composed of chitin.
Reason (R): Chitin, a complex polysaccharide, provides structural strength and rigidity.
14. Assertion (A): In a dorsiventral leaf, palisade parenchyma is located adaxially.
Reason (R): The primary function of palisade parenchyma is the storage of water.
15. Assertion (A): Cockroaches are known to be vectors for several diseases.
Reason (R): Cockroaches frequent and feed upon waste and unhygienic materials.
16. Assertion (A): The inner membrane of mitochondria is deeply folded into cristae.
Reason (R): Cristae increase the surface area for ATP-generating chemical reactions. CBSE Class 11 Biology Half Yearly Paper
SECTION B
17. A botanist observes two flowering plants—one displaying floral parts in multiples of three, the other in fours or fives. Which structural feature of their vascular bundles distinguishes these two groups, and how does it support their classification into monocots and dicots?
18. A newly discovered microorganism exhibits autotrophic behaviour in sunlight but switches to heterotrophy in darkness. To which group of Protista does it likely belong, and what are two defining characteristics of this group that explain its dual mode of nutrition?
19. When comparing the internal anatomy of a roundworm and a cockroach, a key difference emerges in their coelomic cavities. What type of coelom is present in each organism, and how does this reflect their evolutionary complexity
20. The Biuret test reveals the presence of peptide bonds through a distinct colour change. What molecular groups are linked by these bonds, and how are they formed during protein synthesis?
21. A cell undergoing synapsis and crossing over is observed under the microscope. Which type of cell division is this, and why are these processes biologically significant for genetic variation in organisms?
SECTION C
22. An alga is classified under Phaeophyceae based on its unique pigment profile and food storage strategy. Which pigments dominate in this group, and what is the primary stored food product that confirms its identity?
23. In certain plant species, adventitious roots evolve beyond their typical roles of absorption and anchorage. Identify one such structural modification and explain its specialised function in the plant’s survival or adaptation.
24. A double-membraned organelle with its own DNA is often dubbed the “powerhouse of the cell.” What is the name of this organelle, and how does it contribute to the synthesis of the cell’s energy currency?
25. The plasma membrane’s dynamic nature is captured in a specific structural model. What is the name of this model, and which lipid forms the foundational bilayer that enables membrane fluidity and selective permeability?
26. Gamete formation in sexually reproducing organisms involves a critical reduction in chromosome number. During which phase of cell division does this reduction occur, and why is it essential for maintaining genetic stability across generations?
27. The DNA molecule’s architecture allows for precise strand interaction through its sugar-phosphate backbone and nitrogenous bases. What is the term for this strand-to-strand interaction, and what rule governs the pairing of its nitrogenous bases?
28. Discuss, “The respiratory pathway is amphibolic”.
SECTION D
29. Case Study 1
A farmer observes two different types of flowering plants in his field. Plant A has a taproot system, and its leaves exhibit reticulate venation. Plant B has a fibrous root system, and its leaves show parallel venation. CBSE Class 11 Biology Half Yearly Paper
(a) Based on root and venation patterns, identify the class (Monocot/Dicot) for Plant A and Plant B.
(b) State one difference in the number of cotyledons between the seeds of these two plant classes. (c) The floral parts of these plants also show a difference in number. Mention the nature of this difference.
OR
The stem of one of these classes shows secondary growth. Identify the class and the meristem responsible for this growth.
30. Case Study 2
A solution containing a biological polymer, when treated with iodine, gives a blue-black colour. Another polymer, when treated with Benedict’s reagent after hydrolysis, gives a brick-red precipitate.
(a) Identify the two polymers (Biomolecules) based on the colour tests mentioned.
(b) Name the monomeric unit of the polymer that gave a positive test with iodine.
(c) State one structural difference between the two polymers identified.
OR
The brick-red precipitate indicates the presence of a specific chemical group. Name the group and the type of bond that was broken during hydrolysis to release it. CBSE Class 11 Biology Half Yearly Paper
SECTION E
31. A comparative analysis of the Animal Kingdom reveals distinct body plans and complexity levels.
(a) Prepare a comparison between the Phylum Annelida and the Phylum Arthropoda based on:
(i) Type of body cavity (Coelom)
(ii) Circulatory system
(iii) Body segmentation (b) The presence of a notochord defines a specific phylum. Name the phylum and list any two of its fundamental characteristics.
Or
The anatomical study of a frog reveals adaptations for its amphibious life.
(a) Draw a well-labelled diagram of the digestive system of a frog.
(b) Mention the specific role of any two associated digestive glands in the process of digestion.
32. The structural details of a cell provide insights into its function.
(a) Draw a well-labelled diagram of a chloroplast as seen under an electron microscope.
(b) Differentiate between a prokaryotic cell and a eukaryotic cell based on:
(i) Nuclear membrane
(ii) Membrane-bound organelles
(iii) Chromosome type
OR
The diverse roles of proteins are a consequence of their complex structure.
(a) Illustrate the structure of a generic amino acid.
(b) Differentiate between essential and non-essential amino acids.
(c) Justify the statement: “The function of a protein is dictated by its three-dimensional structure.”
33. The process of photosynthesis is central to life on Earth.
(a) The internal structure of a C4 plant leaf shows a distinctive feature known as ‘Kranz Anatomy’. Identify the two types of cells involved in this anatomy and their specific roles.
(b) List two key differences between the C3 and C4 pathways of carbon fixation.
OR
Energy transfer within the cell involves specific cycles.
(a) Differentiate between cyclic and non-cyclic photophosphorylation based on:
(i) Pathway of electrons
(ii) Photolysis of water
(iii) End products (b) The final stage of aerobic respiration involves the synthesis of the maximum ATP. Name the metabolic pathway and its location in the cell.