ANNUAL EXAMINATION – February 2026
CLASS: XI
SUBJECT: BIOLOGY
SET: B
Maximum Marks: 70
Time: 3 Hours
General Instructions:
All questions are compulsory.
This question paper has four sections.
Read the questions carefully before answering.
Section A has 12 questions of 1 mark each.
Wherever necessary, neat and properly labelled diagrams must be drawn.
Section – A
Q. No. 1 to 12 are multiple choice questions. Choose and write the correct answer.
1.Which fungus is edible?
(A) Puccinia
(B) Agaricus
(C) Ustilago
(D) Rhizopus
2.Pteridophytes reproduce by
(A) Seeds
(B) Spores
(C) Vegetative buds
(D) Cones
3.Flame cells are associated with
(A) Annelida
(B) Platyhelminthes
(C) Mollusca
(D) Arthropoda
4.Hypogynous flower has
(A) Inferior ovary
(B) Superior ovary
(C) Half inferior ovary
(D) No ovary
5. Bundle sheath surrounds
(A) Xylem
(B) Vascular bundle
(C) Phloem
(D) Pith
6. Phosphodiester bond links
(A) Sugars
(B) Amino acids
(C) Nucleotides
(D) Fatty acids
7. Centromere divides during
(A) Anaphase I
(B) Anaphase II
(C) Metaphase I
(D) Telophase I
8. Seed dormancy is broken by
(A) ABA
(B) GA
(C) Ethylene
(D) Cytokinin
9. Asthma is caused due to
(A) Alveolar damage
(B) Inflammation of bronchi
(C) Fluid in lungs
(D) Infection of pleura
10. Valve between left atrium and ventricle is
(A) Tricuspid
(B) Bicuspid
(C) Semilunar
(D) Coronary
11. Nodes of Ranvier are gaps in
(A) Axon
(B) Dendrite
(C) Myelin sheath
(D) Cell body
12. Counter-current mechanism operates in
(A) PCT and DCT
(B) Loop of Henle and vasa recta
(C) Bowman's capsule
(D) Collecting duct only
Questions No. 13 to 16 consist of two statements – Assertion (A) and Reason (R).
Choose the correct option.
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 of A.
C. A is true but R is false.
D. A is false but R is true.
13.Assertion: Frogs are cold-blooded animals.
Reason: Body temperature of frogs depends on the environment.
14.Assertion: Plasma membrane is selectively permeable.
Reason: Plasma membrane provides mechanical support to the cell.
15.Assertion: Skeletal muscles are striated.
Reason: Striations are due to arrangement of actin and myosin filaments.
16.Assertion: ADH regulates water balance in the body.
Reason: ADH is secreted by adrenal cortex.
Section – B
17.(A) Housefly belongs to which family?
(B) Write the order of wheat.
18. Write two features of spores of slime moulds.
19. How are cnidoblasts helpful?
20. Why does emphysema reduce breathing efficiency?
21. How do synaptic vesicles work?
Section – C
22. Name the structure that gives rise to the leafy stage of moss. Also, mention any four important features of the leafy stage.
23. (A) How are bulliform cells formed?
(B) State the position of cambium in a dicot stem.
24. Draw a neat and well-labelled diagram of the human female reproductive system.
25. (A) Write the chemical structure of adenosine.
(B) Write the chemical formula of serine.
26.(A) In which phase of meiosis does the synaptonemal complex dissolve?
(B) In which phase of meiosis does termination of chiasmata occur?
(C) Write the significance of meiosis.
27. (A) Write the function of melatonin.
(B) Name the peptide hormone secreted by the juxtaglomerular cells of the kidney.
(C) Name the hormone secreted by corpus luteum.
28. Draw a neat and labelled diagram of the TCA cycle.
Section – D
29.Certain animal cells showed active movement and frequent changes in shape. Microscopic observation revealed a network of protein filaments extending throughout the cytoplasm. Disruption of this network resulted in loss of these intracellular transport.
(A) What is this network of protein filaments called?
(B) Which protein forms microfilaments?
(C) Which cytoskeletal component is tubular in structure?
(D) Which cell organelle helps in the formation of cilia and flagella?
30. A nephron is observed under a microscope. Blood enters the glomerulus where filtration occurs. Useful substances like glucose, salts, and water are reabsorbed in the renal tubules. Waste products remain in the filtrate and are passed to the collecting ducts for elimination. The nephron plays an important role in maintaining homeostasis.
(A) Identify the parts labelled C and D.
(B) Which structure filters blood in a nephron?
(C) Where does reabsorption of useful substances occur?
(D) Where does the final urine collect before excretion?
Section – E
31.(A) Draw a cycle showing ATP synthesis through chemiosmosis.
(B) Name the enzyme located on the stroma side of the thylakoid membrane.
(C) What is the absorption maximum of Photosystem I (PS I)?
32. (A) Define stroke volume.
(B) What is joint diastole?
(C) Explain the QRS complex of an electrocardiogram (ECG).
33. (A) Draw a well-labelled diagram of the human skull.
(B) What is the neural canal?
