Biology Model Paper 2025

The Bihar Board Class 12 Biology Model Paper 2025 is an ideal resource for students preparing for their 2026 board exams. This model paper contains important questions based on the latest syllabus, including both objective and subjective types, helping you improve your speed and accuracy. Designed according to the Bihar Board exam pattern, it aims to boost your confidence and ensure effective preparation for your Biology exam.

Table of Contents

Class 12 – Board Examination Pattern

Maximum Marks: 100
Time Allowed: 3 Hours

General Instructions:

All questions are compulsory.
The question paper consists of three sections A, B, and C.
Marks for each question are indicated against it.
Use of calculators is not permitted.
Draw diagrams wherever necessary.
Answer must be written clearly and neatly.

Section A – Objective Type Questions

(70 Questions × 1 mark each = 70 marks)

Attempt all questions. Choose the correct option.

Who is regarded as the “Father of Genetics”?
a) Charles Darwin
b) Gregor Mendel
c) Hugo de Vries
d) Thomas Hunt Morgan
The functional unit of kidney is:
a) Nephron
b) Alveoli
c) Neuron
d) Glomerulus
Which organelle is called the “Powerhouse of the cell”?
a) Ribosome
b) Nucleus
c) Mitochondria
d) Golgi body
The universal donor blood group is:
a) A
b) B
c) AB
d) O
Which pigment is responsible for photosynthesis?
a) Carotene
b) Xanthophyll
c) Chlorophyll
d) Anthocyanin
Insulin is secreted by:
a) Liver
b) Pancreas
c) Thyroid
d) Adrenal gland
Which vitamin is synthesized in the skin in presence of sunlight?
a) Vitamin A
b) Vitamin C
c) Vitamin D
d) Vitamin K
Which part of the brain controls balance and posture?
a) Cerebrum
b) Cerebellum
c) Medulla
d) Pons
The smallest unit of life is:
a) Atom
b) Cell
c) Tissue
d) Organ
Which blood vessels carry blood away from the heart?
a) Veins
b) Arteries
c) Capillaries
d) Lymph vessels
Sex in humans is determined by:
a) XX–XY mechanism
b) XO mechanism
c) ZW–ZZ mechanism
d) Environmental factors
DNA replication is:
a) Conservative
b) Semi-conservative
c) Dispersive
d) None of these
Which of the following is a connecting link between plants and animals?
a) Euglena
b) Paramecium
c) Amoeba
d) Plasmodium
Which tissue transports water in plants?
a) Phloem
b) Xylem
c) Cambium
d) Epidermis
The site of protein synthesis is:
a) Nucleus
b) Ribosome
c) Mitochondria
d) Lysosome
Which of the following is a vector-borne disease?
a) AIDS
b) Tuberculosis
c) Malaria
d) Pneumonia
The longest bone in human body is:
a) Tibia
b) Femur
c) Humerus
d) Radius
The contractile unit of muscle is:
a) Nephron
b) Sarcomere
c) Myosin
d) Axon
Which is known as the suicide bag of the cell?
a) Nucleus
b) Lysosome
c) Ribosome
d) Golgi body
Which organ is affected in Hepatitis?
a) Heart
b) Kidney
c) Liver
d) Lungs
Pasteurization of milk was introduced by:
a) Robert Koch
b) Louis Pasteur
c) Alexander Fleming
d) Edward Jenner
The exchange of gases in human lungs takes place in:
a) Bronchi
b) Bronchioles
c) Alveoli
d) Trachea
The genetic material in retrovirus is:
a) DNA
b) RNA
c) Protein
d) Carbohydrate
Sickle-cell anemia is caused by:
a) Bacterial infection
b) Mutation in haemoglobin gene
c) Vitamin deficiency
d) Lack of iron
The mode of nutrition in fungi is:
a) Autotrophic
b) Holozoic
c) Saprophytic
d) Parasitic
Green revolution in India is associated with:
a) Dr. B. P. Pal
b) Norman Borlaug
c) M. S. Swaminathan
d) Watson
Darwin proposed the theory of:
a) Mutation
b) Natural selection
c) Germ plasm
d) Inheritance of acquired characters
The main excretory product in human beings is:
a) Ammonia
b) Urea
c) Uric acid
d) Carbon dioxide
The unit of classification is:
a) Genus
b) Family
c) Species
d) Order
Which plant hormone is responsible for cell elongation?
a) Auxin
b) Cytokinin
c) Gibberellin
d) Ethylene
The site of glycolysis is:
a) Nucleus
b) Mitochondria
c) Cytoplasm
d) Chloroplast
Which organ is known as the “Graveyard of RBCs”?
a) Liver
b) Kidney
c) Spleen
d) Pancreas
Which blood group is universal recipient?
a) A
b) B
c) AB
d) O
DNA fingerprinting was developed by:
a) Watson
b) Alec Jeffreys
c) Mendel
d) Rosalind Franklin

Biology Model Paper 2025
AIDS is caused by:
a) Virus
b) Bacteria
c) Protozoa
d) Fungus
Which is the structural and functional unit of nervous system?
a) Axon
b) Dendrite
c) Neuron
d) Synapse
Endocrine glands are:
a) Duct glands
b) Ductless glands
c) Both
d) None
Which vitamin deficiency causes rickets?
a) Vitamin A
b) Vitamin B
c) Vitamin C
d) Vitamin D
The study of fossils is called:
a) Anthropology
b) Paleontology
c) Ecology
d) Geology
The process of formation of gametes is called:
a) Fertilization
b) Gametogenesis
c) Pollination
d) Mitosis
The outermost layer of the skin is:
a) Epidermis
b) Dermis
c) Hypodermis
d) Endodermis
Ciliary muscles are found in:
a) Ear
b) Eye
c) Heart
d) Kidney
Who discovered the structure of DNA?
a) Darwin
b) Mendel
c) Watson and Crick
d) Lamarck
The largest gland in the human body is:
a) Pancreas
b) Liver
c) Thyroid
d) Kidney
In which part of the flower is pollen produced?
a) Stigma
b) Ovary
c) Anther
d) Sepal
Energy currency of the cell is:
a) DNA
b) RNA
c) ATP
d) ADP
Who proposed the Binomial nomenclature system?
a) Darwin
b) Carolus Linnaeus
c) Aristotle
d) Haeckel
The monomers of proteins are:
a) Nucleotides
b) Amino acids
c) Fatty acids
d) Monosaccharides
The term “survival of the fittest” was given by:
a) Darwin
b) Spencer
c) Lamarck
d) Wallace
Which part of the plant absorbs water?
a) Leaf
b) Stem
c) Root hair
d) Flower
The process of conversion of milk into curd is due to:
a) Yeast
b) Lactobacillus
c) Virus
d) Fungi
Which blood cells help in blood clotting?
a) RBC
b) WBC
c) Platelets
d) Plasma
The site of Krebs cycle is:
a) Cytoplasm
b) Nucleus
c) Mitochondrial matrix
d) Chloroplast
The element essential for chlorophyll synthesis is:
a) Iron
b) Magnesium
c) Potassium
d) Calcium
The protein coat of virus is called:
a) Capsid
b) Capsule
c) Cell wall
d) Envelope
The process of loss of water from plants is called:
a) Transpiration
b) Respiration
c) Guttation
d) Excretion
Which scientist is associated with “Germ theory of disease”?
a) Koch
b) Darwin
c) Mendel
d) Harvey
Which organ secretes bile?
a) Pancreas
b) Liver
c) Gall bladder
d) Kidney
In plants, male gametes are produced in:
a) Ovary
b) Anther
c) Style
d) Carpel
Which disease is caused by Plasmodium?
a) Typhoid
b) Cholera
c) Malaria
d) Influenza
The enzyme responsible for DNA replication is:
a) DNA polymerase
b) Ligase
c) Helicase
d) RNA polymerase
The mode of nutrition in Amoeba is:
a) Autotrophic
b) Holozoic
c) Saprophytic
d) Parasitic
Who discovered blood circulation?
a) Mendel
b) William Harvey
c) Pasteur
d) Watson
Which type of RNA carries amino acids?
a) mRNA
b) tRNA
c) rRNA
d) hnRNA
Which part of the ear maintains balance?
a) Cochlea
b) Semicircular canals
c) Pinna
d) Ear drum
The largest muscle in human body is:
a) Biceps
b) Triceps
c) Gluteus maximus
d) Diaphragm
Blood pressure is measured by:
a) Hygrometer
b) Sphygmomanometer
c) Barometer
d) Thermometer
The functional unit of nervous system is:
a) Axon
b) Neuron
c) Dendrite
d) Ganglion
The storage form of carbohydrate in animals is:
a) Starch
b) Glycogen
c) Cellulose
d) Maltose
The covering of the brain is called:
a) Peritoneum
b) Pleura
c) Meninges
d) Pericardium

Section B – Short Answer Questions

(20 Questions × 2 marks each = 40 marks)

Answer any 20 questions. Each question carries 2 marks.
1. Differentiate between Mitosis and Meiosis (any two points).
2. What is the function of ribosomes?
3. Define ecosystem with two examples.
4. Mention two sexually transmitted diseases.
5. Write two differences between Monocot and Dicot plants.
6. Define Biotechnology.
7. What is double fertilization?
8. Define genetic drift.
9. Write two functions of haemoglobin.
10. Name two scientists who proposed cell theory.
11. Differentiate between exocrine and endocrine glands.
12. What are fossils?
13. State Mendel’s Law of Segregation.
14. Write two differences between DNA and RNA.
15. What is tissue culture?
16. Mention two adaptations in xerophytes.
17. Define transpiration.
18. What are plasmids?
19. Name two respiratory diseases caused by smoking.
20. Write the function of xylem and phloem.
Section C – Long Answer Questions

Biology Model Paper 2025

(5 Questions × 5 marks each = 25 marks)

Answer any 5 questions. Each question carries 5 marks.
1. Describe the structure and functioning of the human heart with a neat labelled diagram.
2. Explain Mendel’s experiments on pea plants and his three laws of inheritance.
3. Describe the process of photosynthesis and explain factors affecting it.
4. Write in detail about the human digestive system with the help of a labelled diagram.
5. Explain the structure of DNA and the process of replication.

Conclusion

By practicing with the Biology Model Paper 2025, you can enhance your preparation and gain better command over challenging topics. Regular practice will help you manage exam pressure easily and increase your chances of scoring well. Don’t wait—download the model paper now and start your exam preparation on the right track!

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