ICSE Class 7 Biology Sample Paper with Solutions Set 02

Question 1

Choose the correct answer out of the four available choices given below each question. [15]

1. Which of the following are dividing tissues in case of plants? [1 Mark]
(a) Meristematic tissue
(b) Parenchyma
(c) Sclerenchyma
(d) Collenchyma

Answer: (a) Meristematic tissue

Meristematic tissues are made up of actively dividing cells which produce more cells leading to the growth of the plant body.

Teacher's Note:
a) Meristematic tissues are found in the growing regions of plants, such as the tips of roots and shoots.
b) Students must not confuse meristematic tissue with permanent tissues like parenchyma or sclerenchyma which have lost the ability to divide.

2. Which of the following is not true about parenchyma? [1 Mark]
(a) They are thin walled, oval or round cells.
(b) They are found in the stem, leaves and flowers.
(c) They provide mechanical strength.
(d) They contain leucoplasts and store food.

Answer: (c) They provide mechanical strength.

Mechanical strength in plants is primarily provided by tissues such as collenchyma and sclerenchyma, not parenchyma.

Teacher's Note:
a) Parenchyma cells are generalized living plant cells responsible for storage, photosynthesis, and secretion.
b) Pay close attention to negative questions ("is not true") to avoid selecting correct characteristics by mistake.

3. Amoeba moves with the help of [1 Mark]
(a) Cilia
(b) Flagella
(c) Pseudopodia
(d) Webbed feet

Answer: (c) Pseudopodia

Amoeba extends temporary finger-like projections of cytoplasm called pseudopodia for locomotion and capturing food.

Teacher's Note:
a) This type of movement is known as amoeboid movement.
b) Remember that cilia and flagella are microscopic hair-like structures found in organisms like Paramoecium and Euglena respectively.

4. Which of the following is not a characteristic feature of mammals? [1 Mark]
(a) Four-chambered heart
(b) Warm-blooded
(c) Skin covered with scales
(d) Mammary glands

Answer: (c) Skin covered with scales

The skin of mammals is covered with hair or fur, whereas scales are characteristic of reptiles and fish.

Teacher's Note:
a) Mammals are warm-blooded vertebrates possessing mammary glands to feed their young.
b) Always verify all options before answering, as multiple true features are often listed alongside one exception.

5. Which of the following comes under the category of spiny-skinned organisms? [1 Mark]
(a) Sea urchin
(b) Prawn
(c) Pila
(d) Cockroach

Answer: (a) Sea urchin

The body of a sea urchin belongs to Echinodermata, meaning spiny-skinned organisms.

Teacher's Note:
a) Echinoderms are exclusively marine animals with calcareous spicules or spines.
b) Prawn and cockroach belong to Arthropoda, while Pila belongs to Mollusca.

6. How many molecules of ATP are produced during aerobic respiration? [1 Mark]
(a) 36
(b) 34
(c) 38
(d) 2

Answer: (c) 38

Aerobic respiration completely breaks down glucose in the presence of oxygen to release 38 molecules of ATP.

Teacher's Note:
a) Aerobic respiration yields much more energy compared to anaerobic respiration which produces only 2 ATP.
b) Note that carbon dioxide and water are released as by-products along with energy.

7. Tannin is a _________. [1 Mark]
(a) Human respiratory product
(b) Plant excretory product
(c) Human excretory product
(d) Plant respiratory product

Answer: (b) Plant excretory product

Tannin is a plant waste product stored in plant parts like bark and leaves, often used commercially.

Teacher's Note:
a) Plants do not have specialized excretory organs and store wastes in leaves, bark, or fruits that eventually shed off.
b) Other examples of plant excretory products include gums, resins, and latex.

8. Which of the following body areas are used for skin prick test? [1 Mark]
(a) Hand
(b) Forearm and back
(c) Palm
(d) Shoulder

Answer: (b) Forearm and back

In a skin-prick allergy test, common areas chosen for testing include the inside of the forearm and the back.

Teacher's Note:
a) These areas provide a wide, flat surface convenient for applying multiple allergen extracts simultaneously.
b) This diagnostic test helps identify specific substances that trigger allergic reactions in patients.

9. Which of the following are not striated muscles? [1 Mark]
(a) Muscles of the arm
(b) Muscles of the face
(c) Muscles of the legs
(d) Muscles of the urinary bladder

Answer: (d) Muscles of the urinary bladder

Muscles of the urinary bladder are unstriated or smooth muscles which are involuntary and not under the control of one's will.

Teacher's Note:
a) Striated muscles are voluntary skeletal muscles attached to bones in arms, legs, and face.
b) Smooth muscles are found in the walls of internal organs like the stomach, intestines, and urinary bladder.

10. ___________ are dense connective tissues containing only fibroblasts and collagen fibres. [1 Mark]
(a) Bones
(b) Ligaments
(c) Tendons
(d) Cartilage

Answer: (c) Tendons

Tendons are tough, inelastic cords of dense connective tissue containing parallel bundles of collagen fibres and fibroblasts that connect skeletal muscles to bones.

Teacher's Note:
a) Ligaments connect bone to bone and contain both collagen and elastic fibres.
b) Memorize the specific attachment functions: Tendons connect muscle to bone, while ligaments connect bone to bone.

11. The fine branches given out from the cell body of a nerve cell are [1 Mark]
(a) dendrites
(b) cyton
(c) axon
(d) neuron

Answer: (a) dendrites

Dendrites are short, branched extensions of the neuron that receive electrical impulses from other cells and conduct them toward the cell body.

Teacher's Note:
a) The cell body is called the cyton, and the single long fiber that carries impulses away from the cyton is the axon.
b) A neuron is the entire nerve cell, not just its branches.

12. Unicellular organisms with a proper nucleus belong to [1 Mark]
(a) Protista
(b) Monera
(c) Fungi
(d) Algae

Answer: (a) Protista

Kingdom Protista comprises single-celled eukaryotic organisms that possess a well-defined membrane-bound nucleus.

Teacher's Note:
a) Members of Kingdom Monera (like bacteria) are prokaryotic and lack a true nucleus.
b) Amoeba and Paramoecium are classic examples of unicellular protists.

13. Which of the following is not an arthropod? [1 Mark]
(a) Prawn
(b) Butterfly
(c) Earthworm
(d) Spider

Answer: (c) Earthworm

Earthworms belong to Phylum Annelida, characterized by segmented bodies, whereas prawns, butterflies, and spiders are arthropods with jointed appendages.

Teacher's Note:
a) Arthropoda is the largest phylum in the animal kingdom, characterized by chitinous exoskeletons and jointed legs.
b) Annelids have soft, segmented bodies without jointed limbs.

14. Stomata are present on the surface of [1 Mark]
(a) Leaves
(b) Roots
(c) Stem
(d) Flower

Answer: (a) Leaves

Stomata are tiny microscopic pores located primarily on the lower epidermis of leaves for gaseous exchange and transpiration.

Teacher's Note:
a) Each stoma is surrounded by two kidney-shaped guard cells that regulate its opening and closing.
b) While some herbaceous stems may have stomata, leaves are the primary and most abundant site.

15. Which of the following constitutes an organ? [1 Mark]
(a) Tissues
(b) Organism
(c) Organ System
(d) None of the above

Answer: (a) Tissues

Different types of tissues group together structurally and functionally to form an organ (e.g., epithelial, connective, and muscular tissues forming the stomach).

Teacher's Note:
a) The biological hierarchy runs from cell to tissue to organ to organ system to organism.
b) Do not confuse an organ with an organ system, which is a collection of multiple organs working together.

Question 2

A. Name the following. [5]

1. Tissue that transports water and minerals in plants. [1 Mark]

Answer: Xylem

Teacher's Note:
a) Xylem is the complex permanent vascular tissue responsible for upward conduction of water and dissolved minerals from roots to leaves.
b) Students should remember that phloem is responsible for transporting prepared food.

2. Network of hyphae in fungi. [1 Mark]

Answer: Mycelium

Teacher's Note:
a) Hyphae are thread-like filaments that collectively form the vegetative body of a fungus called mycelium.
b) Spell the biological term carefully to avoid spelling deductions.

3. Muscles found only in the heart. [1 Mark]

Answer: Cardiac muscles

Teacher's Note:
a) Cardiac muscles are involuntary, striated muscles that contract rhythmically without getting fatigued throughout life.
b) They possess intercalated discs that allow rapid impulse transmission between cells.

4. Another name for the brain box. [1 Mark]

Answer: Cranium

Teacher's Note:
a) The cranium is the bony structure enclosing and protecting the delicate human brain.
b) It forms the upper and back part of the skull.

5. Substances that cause allergies. [1 Mark]

Answer: Allergens

Teacher's Note:
a) Common allergens include dust, pollen, certain food items, and animal dander.
b) They trigger an abnormal immune response in sensitive individuals releasing chemicals like histamine.

B. Fill in the blanks. [5]

1. The basophils release an inflammatory chemical called ____________ during an allergic reaction. [1 Mark]

Answer: Histamine

Teacher's Note:
a) Basophils are a type of white blood cell involved in inflammatory and allergic responses.
b) Histamine causes blood vessels to dilate and results in allergy symptoms like swelling and itching.

2. __________transmit messages towards the cell body. [1 Mark]

Answer: Dendrites

Teacher's Note:
a) Dendrites act as receptors bringing signals into the cyton.
b) In contrast, axons carry impulses away from the cell body.

3. In a mitochondrion, ________on the inner membrane serve to increase the surface area for the formation of ATP. [1 Mark]

Answer: Cristae

Teacher's Note:
a) Cristae are fold-like projections of the inner mitochondrial membrane.
b) Mitochondria are known as the powerhouse of the cell because they synthesize ATP during cellular respiration.

4. ______________ are called amphibians of plant kingdom. [1 Mark]

Answer: Bryophytes

Teacher's Note:
a) Bryophytes (such as mosses) live on land but require water for fertilization and sexual reproduction, hence called amphibians of the plant kingdom.
b) They lack true vascular tissues (xylem and phloem).

5. The body is said to have _____________ symmetry if it can be divided into two identical halves along any plane. [1 Mark]

Answer: Radial

Teacher's Note:
a) Radial symmetry is typically observed in sessile or slow-moving aquatic animals like hydra and starfish.
b) Bilateral symmetry allows division into identical halves along only one vertical central plane.

Question 3

A. Match the following. [5]

Teacher's Note:
a) Matching questions test broad conceptual linkages across different biological chapters.
b) Ensure correct matching pairs are clearly written out or mapped without ambiguity.

B. Observe the given diagram and answer the following questions: [5]

[Figure: A potted plant leaf partly covered with a black paper strip in the shape of a star (Original), and the same leaf tested with iodine solution after treatment showing blue-black color everywhere except the star-shaped covered region which remains brown.]

(a) Why leaf is covered with black paper strip? [1 &frac{2}{3} Marks]

Answer: Leaf is covered with a black strip so that that specific part of the leaf does not receive sunlight.

Teacher's Note:
a) The black paper blocks light transmission completely.
b) This creates a controlled comparative area to test the necessity of sunlight.

(b) What is the aim of this experiment? [1 &frac{2}{3} Marks]

Answer: The aim of this experiment is to show that sunlight is necessary for photosynthesis.

Teacher's Note:
a) Starch formation occurs only where sunlight is available for photosynthesis.
b) Iodine test turns starch blue-black and leaves unstressed areas brown.

(c) Is destarching of plant necessary before performing this experiment? Why? [1 &frac{1}{3} Marks]

Answer: Yes, destarching is necessary because during this period, all pre-existing starch from the leaves is removed to storage organs so that leaves show no starch initially, ensuring that any starch detected after the experiment is freshly formed under experimental conditions.

Teacher's Note:
a) Destarching is done by keeping the potted plant in a dark room for 24 to 48 hours.
b) This eliminates false positive iodine test results caused by previously stored starch.

Question 4

A. [5]

(a) Classify the following plants as monocots and dicots-Rice, Pea, Grass, Brinjal. [2 Marks]

Answer:
Monocots: Rice, Grass
Dicots: Pea, Brinjal

Teacher's Note:
a) Monocots have seeds with a single cotyledon, parallel leaf venation, and fibrous roots.
b) Dicots have seeds with two cotyledons, reticulate venation, and tap roots.

(b) State any three points of differences between monocots and dicots. [3 Marks]

Answer:

Teacher's Note:
a) Present differences clearly in tabular format for maximum clarity.
b) Ensure corresponding points match across rows.

B. Complete the following table. [5]

Answer:

Teacher's Note:
a) Aves are characterized by feathers, beaks, and oviparous reproduction (laying eggs).
b) Mammals are characterized by hair/fur and viviparous reproduction (giving birth to live young ones).

Question 5

A. State one point of difference between the following on the basis of what is given in the brackets. [5]

1. Striated muscles and unstriated muscles (control) [1 Mark]

Answer: Striated muscles are under the control of one's will (voluntary), while unstriated muscles are not under the control of one's will (involuntary).

Teacher's Note:
a) Always address the specific parameter mentioned in brackets (control).
b) Striated muscles attach to bones, whereas unstriated muscles line internal hollow organs.

2. Xylem and phloem (direction of transport) [1 Mark]

Answer: The movement of materials in xylem is unidirectional (upwards from roots to leaves), whereas the movement in phloem is bidirectional (upwards and downwards).

Teacher's Note:
a) Xylem transports water and dissolved mineral ions.
b) Phloem distributes synthesized organic food from leaves to all parts of the plant body.

3. Molluscs and echinoderms (movement) [1 Mark]

Answer: Molluscs move with the help of a muscular foot, while echinoderms move with the help of tube feet.

Teacher's Note:
a) Molluscs like snails use a ventral muscular foot for crawling.
b) Echinoderms like starfishes use a unique water vascular system operating tube feet for locomotion.

4. Aerobic respiration and anaerobic respiration (amount of energy released) [1 Mark]

Answer: Aerobic respiration releases 38 molecules of ATP, while anaerobic respiration releases 2 molecules of ATP.

Teacher's Note:
a) Aerobic respiration requires oxygen for complete oxidation of glucose.
b) Anaerobic respiration takes place in the absence of oxygen, yielding significantly less energy.

5. Cocci and bacilli (shape) [1 Mark]

Answer: Cocci are spherical in shape, while bacilli are rod-shaped.

Teacher's Note:
a) These are morphological classifications of bacterial cells.
b) Other forms include spirilla (spiral-shaped) and vibrio (comma-shaped).

B. Find the odd one out. [5]

1. Lungs, Bronchi, Trachea, Kidneys [1 Mark]

Answer: Kidneys. (Kidney is a part of the excretory system, while trachea, bronchi, and lungs constitute the respiratory system.)

Teacher's Note:
a) Always state both the odd one out and the biological reason for classification.
b) Trachea, bronchi, and lungs form the primary air-conveying and gas-exchange apparatus of respiration.

2. Annelida, Arthropoda, Reptilia, Nematoda [1 Mark]

Answer: Reptilia. (Class Reptilia belongs to Phylum Vertebrata while Annelida, Arthropoda, and Nematoda belong to invertebrate phyla.)

Teacher's Note:
a) Invertebrates lack a backbone or vertebral column.
b) Reptiles are tetrapod vertebrates characterized by scaly skin.

3. Euglena, Spirogyra, Amoeba, Chlorella [1 Mark]

Answer: Spirogyra. (Spirogyra is multicellular, while Euglena, Amoeba, and Chlorella are unicellular microorganisms.)

Teacher's Note:
a) Spirogyra forms filamentous green algal colonies consisting of multiple cells.
b) Euglena, Amoeba, and Chlorella exist as single-celled entities.

4. Pituitary, Thyroid, Adrenal, Spinal cord [1 Mark]

Answer: Spinal cord. (The spinal cord belongs to the central nervous system, while pituitary, thyroid, and adrenal are endocrine glands.)

Teacher's Note:
a) Endocrine glands secrete chemical messengers called hormones directly into the bloodstream.
b) The spinal cord is a major nerve cord transmitting nervous impulses between brain and body.

5. Penguin, Ostrich, Vulture, Kiwi [1 Mark]

Answer: Vulture. (A vulture can fly, while the penguin, ostrich, and kiwi are flightless birds.)

Teacher's Note:
a) Flightless birds have modified anatomical features such as heavy unkeeled sternum bones.
b) Vultures possess strong wings adapted for soaring and prolonged flight.

Question 6

A. Explain movement in Amoeba and Paramoecium. [5]

[Figure: Diagrams showing Amoeba extending pseudopodia and flowing forward, and Paramoecium with cilia beating and moving along a directional path.]

Answer:
Movement in Amoeba:
1. Amoeba is a unicellular organism that does not have a definite shape.
2. In order to move, it thrusts out temporary finger-like projections called false-feet or pseudopodia in the direction of movement.
3. The cellular contents are pushed forward into the pseudopodium.
4. Amoeba moves forward because of the flowing motion of the cytoplasm, which is termed amoeboid movement.
Movement in Paramoecium:
1. Paramoecium has a slipper-shaped body covered with a flexible membrane called a pellicle.
2. The pellicle is covered with short hair-like structures called cilia.
3. The cilia beat in an organized manner to propel the organism through water, causing it to rotate in a spiral path.
4. It can move forward or backward depending on the direction in which the cilia beat, and can also crawl on its oral side.

Teacher's Note:
a) Clearly distinguish between pseudopodia-based amoeboid movement and cilia-driven ciliary movement.
b) Mention key anatomical terms like pseudopodia, cytoplasm, pellicle, and cilia to secure full credit.

B. Define the following. [5]

1. Classification [1 Mark]

Answer: Grouping organisms together on the basis of certain common features and characteristics is called classification.

Teacher's Note:
a) Classification organizes biodiversity making study and identification systematic.
b) It forms the basis of biological taxonomy.

2. Binary fission [1 Mark]

Answer: Binary fission is a method of asexual reproduction in which a single parent organism splits to give rise to two identical daughter organisms.

Teacher's Note:
a) It is commonly observed in unicellular organisms like Amoeba and bacteria.
b) Nuclear division is followed by cytoplasmic division.

3. Vertebrates [1 Mark]

Answer: Animals possessing a backbone or vertebral column are called vertebrates.

Teacher's Note:
a) Vertebrates belong to Phylum Chordata.
b) Examples include fish, amphibians, reptiles, birds, and mammals.

4. Photosynthesis [1 Mark]

Answer: The process of synthesizing food using water from the soil and carbon dioxide from the air together with chlorophyll and sunlight is called photosynthesis.

Teacher's Note:
a) Oxygen is released as a by-product of this vital biochemical process.
b) It converts solar energy into chemical energy stored as glucose.

5. Sensory nerve [1 Mark]

Answer: Sensory nerve contains only sensory nerve fibres which bring nerve impulses from sense organs to the brain or the spinal cord.

Teacher's Note:
a) Sensory nerves are afferent pathways transmitting environmental stimuli signals.
b) In contrast, motor nerves transmit responses from the central nervous system to effectors like muscles.

Question 7

A. Answer the following.

1. What are the symptoms of food allergy? [2 Marks]

Answer:
Symptoms of food allergy include:
1. Abdominal pain and bloating.
2. Vomiting and diarrhoea.
3. Itchy skin and swelling of the skin.

Teacher's Note:
a) Food allergies activate the immune system abnormally against specific food proteins.
b) List at least two or three clear physiological symptoms for full marks.

2. In which phylum is liverfluke placed? Why? [3 Marks]

Answer:
1. Liverfluke is placed in Phylum Platyhelminthes (flatworms).
2. It is a small, soft, flattened, unsegmented parasitic worm.
3. It does not possess a true body cavity (coelom), which is why it is classified under Platyhelminthes.

Teacher's Note:
a) Platyhelminthes are bilaterally symmetrical and mostly parasitic.
b) Mentioning flat unsegmented morphology and absence of coelom covers all value points.

B. Answer the following.

1. What are the main functions of cerebellum? [2 Marks]

Answer:
The main functions of the cerebellum are:
1. It helps in maintaining the posture and equilibrium of our body.
2. It enables us to make precise, coordinated, and accurate voluntary muscle movements.

Teacher's Note:
a) The cerebellum is located behind the cerebrum at the base of the brain.
b) Damage to the cerebellum leads to loss of balance and uncoordinated movements.

2. Leaves of a healthy potted plant were coated with vaseline. Will this plant remain healthy for long? Give reasons. [3 Marks]

Answer:
No, the plant will not remain healthy for a long time because:
1. Coating leaves with vaseline blocks the stomata, preventing the plant from getting adequate oxygen for respiration.
2. Carbon dioxide intake required to carry out photosynthesis is obstructed.
3. The upward movement of water and minerals (transpirational pull) would be severely hampered due to lack of transpiration.

Teacher's Note:
a) Vaseline creates an airtight and watertight barrier over stomatal pores.
b) Stomatal blockage disrupts all three major physiological processes: respiration, photosynthesis, and transpiration.