Class 11 Biology Paper - Final exam 2026

 

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?

 

Allen's Rule

Image : Arctic foxes having shorter ears and limbs compared to desert-dwelling foxes

Allen's Rule Endothermic animals (warm-blooded animals like mammals and birds) living in colder climates tend to have shorter limbs, ears, and other appendages to minimize heat loss. In contrast, animals living in warmer climates tend to have longer limbs, ears, and other appendages to increase heat loss and help regulate their body temperature. This adaptation helps animals conserve heat in cold environments and dissipate heat in warm environments, improving their overall survival and fitness. Examples include: 

Arctic foxes having shorter ears and limbs compared to desert-dwelling foxes. (See Image)

Polar bears having smaller ears and shorter limbs compared to tropical bears.

The Living World. (NCERT based MCQs)

 The Living World.

(By. Ashwani  Kumar)

1. How many species are known and described approximately?

A) 1 million

B) 2.5 million

C) 1.7-1.8 million —

D) 0.5 million

Ans. C

2. What does ICBN stand for?

A) International Council for Biological Names

B) Indian Code for Botanical Nomenclature

C) International Code for Botanical Nomenclature —

D) International Committee for Biological Naming

Ans: C

3. Which code is used by animal taxonomists for naming animals?

A) ICZN 

B) ICBN

C) IBSC

D) NCERT

Ans A.

4. What does ICZN stand for?

A) International Community of Zoological Nomenclature

B) International Code of Zoological Nomenclature —

C) International Committee for Zonal Names

D) Indian Code for Zoological Naming

Ans: B

5. What is the main advantage of scientific names?

A) They are in English

B) They help in memorising faster

C) Each organism has only one universally accepted name —

D) They are easy to pronounce

Ans. C

6.. The system of giving names with two components is called —

A) Monomial nomenclature

B) Trinomial nomenclature

C) Binomial nomenclature —

D) Dual taxonomy

Ans: C

9. Who introduced the binomial system of nomenclature?

A) Charles Darwin

B) Gregor Mendel

C) Carolus Linnaeus —

D) Aristotle

Ans: C

10. In the scientific name Mangifera indica, what does "Mangifera" represent?

A) Species

B) Family

C) Order

D) Genus —

Ans: D

11. In Mangifera indica, what does "indica" represent?

A) Family name

B) Genus

C) Specific epithet —

D) Class

Ans: C

12. Biological names are generally in which language?

A) English

B) Sanskrit

C) Greek

D) Latin 

Ans: D

13. How are biological names written when handwritten?

A) In bold

B) In capital letters

C) Underlined separately —

D) With dots between words

Ans: C

14. How are biological names printed to indicate Latin origin?

A) Bold

B) Underlined

C) Capitalized

D) Italicised —

Ans: D

15. What is the process of giving standard names to organisms called?

A) Classification

B) Nomenclature —

C) Evolution

D) Observation

Ans: B

16. What is the first step before naming an organism scientifically?

A) Reading a textbook

B) Describing and identifying the organism —

C) Photographing it

D) Coloring it

Ans: B

17. Who developed the binomial system of nomenclature?

A) Charles Darwin

B) Gregor Mendel

C) Carolus Linnaeus 

D) Aristotle

Ans: C

18. In a scientific name, which part starts with a capital letter?

A) Specific epithet

B) Genus —

C) Family

D) Species

Ans: B

19.. In a biological name, which part begins with a small letter?

A) Genus

B) Phylum

C) Specific epithet —

D) Kingdom

Ans: C

20. What does the author’s name after the specific epithet indicate?

A) Who named the genus

B) The current scientist studying it

C) The person who first described the species —

D) The one who classified it

Ans: C

21.. What is the process of grouping organisms into categories called?

A) Nomenclature

B) Evolution

C) Classification —

D) Adaptation

Ans: C

22.. What is the scientific term for the process of classifying organisms into taxa?

A) Ecology

B) Taxonomy —

C) Morphology

D) Physiology

Ans: B

23. Early classifications of organisms were based on —

A) Scientific rules

B) Uses of organisms 

C) Size of organisms

D) Ecosystems

Ans: B

24. Which of the following is the correct sequence of steps in taxonomy?

A) Identification → Nomenclature → Characterisation → Classification

B) Classification → Characterisation → Nomenclature → Identification

C) Characterisation → Identification → Classification → Nomenclature —

D) Nomenclature → Classification → Identification → Characterisation

Ans C

25. What is the first step in the process of taxonomy?

A) Nomenclature

B) Characterisation —

C) Identification

D) Classification

Ans: B

26. Identifying to which group an organism belongs is known as —

A) Nomenclature

B) Classification

C) Systematics

D) Identification —

Ans: D

27. Systematics includes which of the following?

A) Only classification

B) Only naming

C) Identification, classification, nomenclature, and study of relationships —

D) Evolutionary study only

Ans: C

28. Which of the following best explains the role of systematics in biology?

A) It helps in digestion

B) It helps in naming organisms

C) It helps understand evolutionary links between species —

D) It explains photosynthesis

Ans. C

29. Who authored the work titled Systema Naturae as part of his classification efforts?

A) Charles Darwin

B) Aristotle

C) Carolus Linnaeus 

D) Gregor Mendel

Ans: C

30. What is the correct term for each rank or step in the taxonomic hierarchy?

A) Species

B) Category 

C) Class

D) Genus

Ans: B

31. What is the lowest taxonomic category in both plants and animals?

A) Genus

B) Species 

C) Order

D) Family

Ans: B

32. What is the correct scientific name for human beings?

A) Homo Sapiens

B) Homo sapiens 

C) homo sapiens

D) Sapiens Homo

Ans: B

33. Which of these pairs belong to the same family Felidae?

A) Lion and cat —

B) Cat and dog

C) Dog and wolf

D) Leopard and wolf

Ans. A

34. The family Canidae includes which of the following?

A) Cats

B) Dogs 

C) Tigers

D) Leopards

Ans: B

35. In plants, which genera belong to the family Solanaceae?

A) Rosa, Nelumbo, Hibiscus

B) Solanum, Petunia, Datura —

C) Zea, Oryza, Triticum

D) Mango, Guava, Jamun

Ans: B

36. Which order includes families like Felidae and Canidae?

A) Primata

B) Solanaceae

C) Carnivora —

D) Polymoniales

Ans: C

37. What category includes families like Solanaceae and Convolvulaceae based on floral characters?

A) Class

B) Order 

C) Genus

D) Species

Ans: B

38. The class Mammalia includes which of the following orders?

A) Solanaceae and Convolvulaceae

B) Carnivora and Primata —

C) Felidae and Canidae

D) Poaceae and Fabaceae

Ans: B

39. What is the next higher category after Class in the animal kingdom?

A) Order

B) Genus

C) Phylum 

D) Species

Ans: C

40. Which of the following classes belong to the same phylum?

A) Mammals and Birds —

B) Amphibians and Algae

C) Reptiles and Ferns

D) Birds and Insects

Ans: A

41. In the animal kingdom classification system, the highest taxonomic category is:

A) Phylum

B) Class

C) Order

D) Kingdom

Ans: D

42. In plants, similar classes are grouped under which higher category?

A) Phylum

B) Order

C) Division

D) Kingdom

Ans: C) Division

43. As we move from species to kingdom, the number of common characteristics among organisms:

A) Increases

B) Remains constant

C) Decreases

D) First increases then decreases

Ans. C 

44. Which of the following statements is TRUE regarding lower taxonomic categories?

A) Fewer characteristics are shared

B) More characteristics are shared

C) They are broader categories

D) They are harder to classify

Ans: B) 

45. The classification problem becomes more complex at:

A) Species level

B) Genus level

C) Kingdom level

D) Family level

Ans: C

46. Mangifera indica (Mango) belongs to which Family?

A. Poaceae

B. Muscidae

C. Anacardiaceae

D. Hominidae

Ans: C.

47. What is the Class of Mangifera indica (Mango)?

A. Dicotyledonae

B. Monocotyledonae

C. Insecta

D. Mammalia

Ans: A.

48. The Division of Mangifera indica is:

A. Chordata

B. Arthropoda

C. Angiospermae

D. Monocotyledonae

Ans: C. 

49. The Order of Homo sapiens is:

A. Mammalia

B. Hominidae

C. Primata

D. Chordata

Ans: C. 

50. . Triticum aestivum belongs to which Order?

A. Sapindales

B. Poales

C. Primata

D. Diptera

Ans: B. 

51. What is the Order of Musca domestica (Housefly)?

A. Primata

B. Diptera

C. Insecta

D. Muscidae

Ans: B. 

52. The Class of Triticum aestivum (Wheat) is:

A. Dicotyledonae

B. Insecta

C. Monocotyledonae

D. Mammalia

Ans C. 

Q. By switching the position of promotor with terminator the definition of coding and template strand could be reversed. How.

 Q. By switching the position of promotor with terminator the definition of coding and template  strand could be reversed. How.

Ans. Switching the position of the promoter and terminator in a DNA sequence would reverse the direction of transcription, which in turn would change which strand serves as the template for mRNA synthesis. Normally, the promoter region is where RNA polymerase binds to initiate transcription, and the terminator signals the end of transcription. 

If you switch their positions, the RNA polymerase would bind at what was previously the terminator and transcribe in the opposite direction, using what was previously the coding (non-template) strand as the template for mRNA synthesis. Consequently, the strand that was previously the coding (non-template) strand would become the template strand, and vice versa, effectively reversing their roles.

Pneumonics for Kreb's Cycle

Number of ATP per mole of Glucose

 To calculate the number of ATP produced by one mole of glucose, we need to multiply the number of ATP produced by one molecule by Avogadro's number, which is 6.022 x 10^23. So, the number of ATP produced by one mole of glucose is 38 x 6.022 x 10^23 = 2.29 x 10^24.