ISC Class 11 Biology Half Yearly Sample Paper 2025: Download Free PDF

Question No.

SECTION A – 20 MARKS

1

Answer the following questions briefly.

(i) Name the phylum whose organisms have comb plates. [1]

(ii) Assertion: In nematodes, body cavity is pseudocoel. [1]

Reason: It is a spacious cavity lined with endoderm.

(a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion

(b) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.

(c) Assertion is true but Reason is false.

(d) Both Assertion and Reason are false.

(iii) Differentiate between Ureotelic and Ammonotelic animals [1]

(iv) Book lungs is one of the respiratory organs of: [1]

(a) Molluscans 

(b) Echinoderms 

(c) Arthropoda 

(d) Annelida

(v) Give a reason for each of the following: [2]

(a) Bryophytes are termed as Amphibians of Plant kingdom.

(b) Life span of Red Blood corpuscles is 120 days.

(vi) Name the special cell of Cnidarians which is shown below and also write its function. [2]

(vii) Give a term for the following: [2]

(a) Volume of air inspired or expired during a normal respiration.

(b) Expulsion of urine from the urinary bladder.

(viii) What causes emphysema in humans? [1]

(ix)  Answer the following questions: [2]

(a) Protein factory was discovered by which scientist ?

(b) Expand FRC.

(x) Define Growth rate [1]

(xi) During a cell cycle, the DNA synthesis occurs how many times ? [1]

(xii) Which of the following is not an influence of Auxin ? [1]

(a) Apical dominance 

(b) Parthenocarpy 

(c) Tropic movements 

(d) Bolting

(xiii) Metaphase chromosomes have two sister chromatids. (True/False) [1]

(xiv) Atrial Natriuretic factor is produced by : [1]

(a) Kidney 

(b) Heart 

(c) Duodenum 

(d) Thyroid gland

(xv) Members of which phylum is known as sponges? [1]

(xvi) Name a Pteridophyte which exhibits heterospory . [1]

SECTION B – 14 MARKS(7x2)

2

Describe Anaphase and Telophase of Mitosis with the help of diagrams.

3

Differentiate between Chlorophyceae and Rhodophyceae based on:

1) Nature of pigments 

2) Composition of cell wall

4

(a) Name the phylum which exhibits following characteristics:

1. Metameric segmentation

2. Water vascular system

3. Soft bodied animal

4. Canal system 

OR

(b) Enlist any four distinguishing characteristics of phylum Arthropoda.

5

John loved eating junk food like chips, burgers and French fries since his child hood. At the age of 40,he started feeling radiating pain in his left arm. According to you, why he felt so ? What suggestions can you give him to improve his overall health?

6

Observe the diagram and answer the following questions:

i) Label A &B and discuss its role in the above process.

ii) Name and explain the process which is carried by this structure.

7

i) Avi had grown cabbage in his farm. He found out that few cabbage plants exhibited long

internodes. Which chemical was responsible for this condition ? Give its two role.

ii)  From the market, Risha bought ripe yellow mangoes. While eating she found out that the fruits

were sour in taste. According to you, which chemical was used by the fruit vendor to ripe

mangoes artificially ? Give two role of that chemical apart from ripening the fruits.

8

SECTION C – 21 MARKS(7x3)

9

Observe the diagram given below and answe the following questions:

i) Name the phylum.

ii) Enlist four distinguishing characters of the phylum mentioned in (ii)

iii)  Identify the organism.

10

Study the table give below:

i) In dengue fever which element of blood decreases in count?

ii) Identify the correct statement from below:

a) They have red colour copper containing pigment

b) RBCs are devoid of nucleus in most of the mammals

c) They are biconvex in shape

d) RBCs are least abundant blood cells

iii) Choose the odd one out with respect to secretions of Basophils.

iv) Give the terms for B, C and D.

11

i) Draw a well labelled diagram of an Auxanometer

ii) Describe the phases of growth in meristems.

12

i) Explain the counter current mechanism briefly.

ii) Redraw the diagram of L.S of Kidney, name and label the parts based on features given below:

1) It transports more of urea and oxygenated blood.

2) The extended part of cortex in medullary area.

3) Area where freshly prepared urine is collected.

13

(a) i) Write a brief note on Clotting of Blood.

ii) Identify the correct statement from below:

a) RBCs are least abundant blood cells

b) They have red colour copper containing pigment

c) RBCs are devoid of nucleus in most of the mammals

d) They are biconvex in shape

iii) In dengue fever which element of blood decreases in count ?

(iv) Give any three differences between an artery and a vein.

OR

(b) Describe various phases of Cardiac cycle.

14

i) Expand RAAS. How it controls blood pressure? Discuss briefly.

ii) Draw a well labelled diagram of a uriniferous tubule.

15

Observe the diagram of Funaria below and answer the following questions :

i) Label the parts D & E.

ii) Describe the life cycle of Funaria.

SECTION D – 15 MARKS (5 X3)

16

Explain Prophase 1 of Meiosis with the help of diagrams.

17

(a) i) Observe the graph given below and answer the following questions:

ii) Explain the mechanism of Breathing showing role of diaphragm and intercostal muscles with the help of diagrams.

OR

(b) Explain chloride shift.

ii) Expand ERV.

iii) Describe the mechanism of transport of carbon dioxide from tissue to lungs.

Diagram

a) Identify the given graph.

b) Locate left ventricle, pulmonary vein and vena cava in the given graph with respect to positions 1,2

and 3.

18

Draw a well labelled diagram of internal structure of a Human heart.

CHECK: ISC Class 11 Half Yearly Biology Sample Paper 2025; Download Free PDF