Plus 1 Biology Question Paper (PDF) with Answers | 2025 February Model Exam

+1 Biology Model Exam 2025

FIRST YEAR HIGHER SECONDARY
MODEL EXAMINATION, FEBRUARY 2025

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PART-A: BOTANY

I. Answer any 3 questions from 1 to 5. Each question carries 1 score. (3x1=3)

01) Viruses are covered by a protein coat, what is its name?
✅ Capsid.
02) In most of the higher plants, the growing apical bud inhibit the growth of lateral buds. This phenomenon is called ________.
✅ Apical dominance.
03) In which stage of Mitosis, chromatids are separated and moving to opposite poles?

(a) Prophase     (b) Metaphase    

(c) Anaphase     (d) Telophase

✅ (c) Anaphase.
04) The fusion between one large non-motile female gamete and a small motile male gamete is called ________.
✅ Oogamy.
05) Observe the relation between the first pair and fill in the blanks.

Outer layer of seed coat: Testa;

Inner layer of seed coat: ________.

✅ Tegmen.

II. Answer any 9 questions from 6 to 16. Each question carries 2 score. (9x2=18)

06) Plants can get along without respiratory organs. Write two peculiarities that helps plants to do so.
Answer:

• Each plant part takes care of its own gas-exchange needs; there is very little transport of gases from one plant part to another.

• Plants do not present great demands for gas exchange.

07) Write two characteristics features of the vascular bundle of Dicot stem.
Answer:

• Vascular bundles are arranged in a ring.

• They are conjoint, open, and with endarch protoxylem.

08) Match the following.
AB
a) Anabaenai) Pellicle
b) Gonyaulaxii) Heterocyst
c) Euglenaiii) Plasmodium
d) Slime mouldsiv) Red tide
Answer:
AB
a) Anabaenaii) Heterocyst
b) Gonyaulaxiv) Red tide
c) Euglenai) Pellicle
d) Slime mouldsiii) Plasmodium
09) a) Who discovered ribosomes?

b) Which are the chemical components of Ribosomes?

Answer:

a) George Palade.

b) RNA and proteins.

10) Write the peculiarities of cells seen at the Meristematic phase of growth.
Answer:

• Cells are rich in protoplasm.

• Cell walls are thin.

• Cells divide constantly.

11) A chromatographic separation of leaf pigments shows that leaf consist 4 pigments. Write the name and colour of each pigment.
Answer:

Chlorophyll a: Bright or blue green.

Chlorophyll b: Yellow green.

Xanthophylls: Yellow.

• Carotenoids: Yellow to yellow-orange.

12) The spread of living Pteridophytes is limited and restricted to narrow geographical regions. Why?
Answer:

This is because the gametophytes (prothallus) require cool, damp, and shady places to grow and also need water for fertilization.

13) Characteristic features of Dorsi-ventral leaf and iso-bilateral leaves are given below. Arrange them in appropriate columns.

• Mesophyll is not differentiated.

• Stomata are distributed more at the abaxial epidermis.

• Stomata are equally distributed on both surfaces.

• Mesophyll is differentiated into Palisade and Spongy layers.

Answer:
Dorsi-ventral leaf (Dicot)Iso-bilateral leaf (Monocot)
Stomata are distributed more at the abaxial epidermisStomata are equally distributed on both surfaces
Mesophyll is differentiated into Palisade and Spongy layers.Mesophyll is not differentiated.
14) a) Observe the diagram of Mitochondria and label the parts marked as A and B.

b) What is the role of Mitochondria in a cell?

Answer:

a) A-Matrix, B-Crista.

b) They are the sites of aerobic respiration and produce cellular energy in the form of ATP ("Powerhouses of the cell").

15) According to Chemi-osmotic hypothesis, proton gradient formed in a membrane is required for the synthesis of ATP. Write two reasons for the development of proton gradient in thylakoid of Chloroplast.
Answer:

• Photolysis (splitting) of water takes place on the inner side of the membrane, releasing protons into the lumen.

• As electrons move through the photosystems, protons are transported across the membrane.

16) a) What is respiratory climatic?

b) Which plant hormone is responsible for this?

Answer:

a) It is the sudden rise in the rate of respiration during the ripening of fruits.

b) Ethylene.

17) a) It is better to consider respiratory pathway as an amphibolic pathway rather than as a catabolic one. Why?

b) Observe the amphibolic pathway and write names of A, B, C and D.

Answer:

a) Because it involves both catabolism (breakdown) and anabolism (synthesis) of molecules.

b) A-Fats, B-Carbohydrates, C-Proteins, D-Pyruvic acid.

18) Observe the given floral diagram of solanaceae and answer the following questions:

a) Identify the aestivation of corolla.

b) In this diagram, petals are seen attached to Stamens. Write the name of this condition.

c) Write two features of gynoecium.

Answer:

a) Valvate aestivation.

b) Epipetalous.

c) Bicarpellary, syncarpous; ovary superior; placenta swollen with many ovules.

19) a) Write the name of substage of Prophase I in which the following events takes place:

i) Synapsis     ii) Terminalisation of Chiasma.

b) Name the enzyme that catalyse crossing over.

c) What is the significance of crossing over.

Answer:

a) i) Zygotene , ii) Diakinesis.

b) Recombinase.

c) It leads to variations in the genetic material of offspring.

20) Write three differences between Cyclic and Non-cyclic photophosphorylation.
Answer:

• Cyclic: Only PS I is involved; only ATP is produced; electrons circulate within the photosystem.

• Non-cyclic: Both PS I and PS II are involved; both ATP and NADPH are produced; photolysis of water occurs.

PART-B: ZOOLOGY

I. Answer any 3 questions from 1 to 5. Each question carries 1 score. (3x1=3)

01) Write one word for the following:

a) Red coloured oxygen storing pigment in muscle.

b) Inflammation of joints.

Answer:

a) Myoglobin    b) Arthritis.

02) Protein part of the enzyme is called ________.
Answer: Apoenzyme.
03) An endocrine organ that degenerates with age.
Answer: Thymus.
04) Select the generic name and specific epithet from the table and write scientific name of housefly.
Generic nameSpecific epithet
Mangiferadomestica
Muscaindica
Answer: Musca domestica.
05) CO₂ + H₂O ⇌ H₂CO₃. Name the enzyme which catalyse this reaction.
Answer: Carbonic anhydrase.

II. Answer any 9 questions from 6 to 16. Each question carries 2 score. (9x2=18)

06) Diagrammatic representation of a standard ECG is given below.

a) What does P and T wave denote?

b) Mention the clinical significance of ECG.

Answer:

a) P-wave: Depolarisation of the atria. T-wave: Repolarisation of the ventricles.

b) Any deviation from the standard ECG shape indicates a possible heart abnormality or disease.

07) Observe the relationship between first pair of words and write a suitable word for the second word pair.

a) Hyperglycaemic hormone: Glucagon;

Hypoglycaemic hormone: ________.

b) Hyposecretion of growth hormone: Dwarfism;

Hypersecretion of growth hormone: ________.

Answer:

a) Insulin

b) Gigantism

08) a) Identify the cell.

b) Mention any 2 functions.

Answer:

a) Cnidoblast (Stinging cell).

b) Anchorage, defense, and capture of prey.

09) Co-factors are essential for enzyme activity.

a) Name any two co-factors.

b) What happens to the catalytic activity of enzyme when co-factor is removed from it?

Answer:

a) Prosthetic groups, Co-enzymes, Metal ions (any two).

b) The catalytic activity of the enzyme is lost.

10) Match the following.
Column AColumn B
PlatyhelminthesGills
AnnelidaMalpighian tubules
ArthropodaFlame cells
MolluscaNephridia
Lungs
Answer:
Column AColumn B
PlatyhelminthesFlame cells
AnnelidaNephridia
ArthropodaMalpighian tubules
MolluscaGills
11) a) Identify the diagram.

b) Label the parts marked as A and B.

Answer:

a) Female reproductive system of Frog.

b) A-Oviduct, B-Ovary.

12) Complete the table using hints given: (Transferase, Ligase, Oxido-reductase, Lyase, Isomerase)
A B
……(a)…… Catalyse oxidoreduction between two substrates S and S′
……(b)…… Catalyse the transfer of a group G (other than H) between S and S′
……(c)…… Catalyse interconversion of isomers
……(d)…… Catalyse the linking together of two compounds
Answer:

(a) Oxidoreductase

(b) Transferase

(c) Isomerase

(d) Ligase.

13) Name the following:

a) Accumulation of urea in blood.

b) Stones crystallised salts formed in Kidney.

c) Inflammation of glomeruli.

d) Process used to remove urea from those patients, whose kidneys do not function properly.

Answer:

a) Uraemia

b) Renal calculi

c) Glomerulonephritis

d) Haemodialysis

14) The functioning of heart is regulated and maintained by nodal tissues and conducting system.

a) Identify any three components/parts of the conducting system of human heart from the diagram. (Hint: Parts marked as A, B and C)

b) Which is the nodal tissue that initiate heartbeat?

Answer:

a) A- SA Node

    B- AV Node

    C- Bundle of His.

b) SA Node (Sino-atrial node).

15) Special features of four different phyla are given. Identify the phylum.

a) Ciliated comb plates.

b) Chitinous exoskeleton.

c) Water vascular system.

d) File-like rasping organ.

Answer:

a) Ctenophora

b) Arthropoda

c) Echinodermata

d) Mollusca.

16) Contraction of a muscle fibre takes place by the sliding of thin filament over the thick filaments.

a) Which theory explains the process of muscle contraction?

b) Name two contractile proteins seen in muscles.

Answer:

a) Sliding filament theory.

b) Actin and Myosin.

III. Answer any 3 questions from 17 to 20. Each question carries 3 score. (3x3=9)

17) Synapse is the junction between two neurons.

a) What are the two types of synapses?

b) How do they differ from each other?

Answer:

a) Electrical synapse and Chemical synapse.

b) In electrical synapses, neurons are in very close proximity and impulse transmission is very fast; in chemical synapses, there is a gap (synaptic cleft) and neurotransmitters are involved.

18) Some cnidarians exhibit two body forms as shown in figure.

a) Name the body forms 'A' and 'B'.

b) Write any two differences between them.

Answer:

a) A-Medusa, B-Polyp.

b) Medusa is umbrella-shaped and free-swimming. Polyp is cylindrical and sessile.

19) a) Observe the graph and identify the sigmoid curve.

b) Mention the factors which favour the formation of oxyhaemoglobin in alveoli.

c) How many O₂ molecules can a haemoglobin molecule carry?

Answer:

a) Oxygen dissociation curve.

b) High pO₂, low pCO₂, lesser H⁺ concentration, and lower temperature.

c) Four O₂ molecules.

20) Given below is the picture of a renal corpuscle.

a) Name the parts marked as A, B and C.

b) Write the three main steps/processes in urine formation.

Answer:

a) A-Afferent arteriole, B-Efferent arteriole, C-Bowman's capsule.

b) Glomerular filtration, Reabsorption, and Secretion.

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