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ICSE Class 7 Science★ ICSE Class 7 Biology · Full Year Coverage · Board: ICSE

Biology — Tissues, Kingdoms, Plant Life & Human Body Systems

TISSUES — the fabric of life. The FIVE KINGDOMS — how scientists organise ALL living things. How plants make FOOD (photosynthesis) and BREATHE (respiration). And the HUMAN BODY — the nervous system and excretory system. ICSE Class 7 Science.

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1Classify plant tissues: meristematic (cell division) and permanent (simple: parenchyma/collenchyma/sclerenchyma; complex: xylem/phloem)
2Classify animal tissues: epithelial (covering), connective (support), muscular (movement), nervous (signals)
3State Whittaker's Five Kingdoms with key features for each
4State the nervous system structure: CNS (brain+spinal cord) and PNS (nerves); describe the neuron
5Explain reflex action: rapid/automatic/spinal cord (not brain) — example: pulling from hot object
6Name 3 brain parts with functions: cerebrum (thinking), cerebellum (balance), medulla oblongata (involuntary)
7Trace the excretory system: kidneys filter blood → urea → urine → ureters → bladder → urethra
8Name 4 excretory organs and what each excretes

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Why this chapter matters

This ICSE Class 7 Biology chapter covers all major topics for the annual exam: plant tissues (meristematic/simple permanent/complex permanent), animal tissues (epithelial/connective/muscular/nervous), Whittaker's Five Kingdoms, photosynthesis equation and factors, the nervous system (CNS/PNS, neuron, reflex arc, brain parts), and the excretory system (kidneys, urea, urine pathway). The Five Kingdoms table (Monera/Protista/Fungi/Plantae/Animalia with features) is a reliable 5-mark table question. Brain parts (cerebrum/cerebellum/medulla oblongata) with functions are tested annually. The reflex arc diagram is a standard diagram question.

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Biology — Tissues, Classification, Plants & Human Body

1. Tissues (Plant and Animal)

What Is a Tissue?

A group of SIMILAR CELLS that work together to perform a SPECIFIC FUNCTION.

Plant Tissues

Tissue	Function	Location
Meristematic	Cell DIVISION (growth). Small, thin-walled, actively dividing.	Tips of roots and shoots (apical meristem)
Permanent — Simple	Parenchyma (storage, photosynthesis). Collenchyma (flexible support). Sclerenchyma (strength — dead cells).	Throughout the plant
Permanent — Complex	Xylem (transports WATER and MINERALS UP from roots). Phloem (transports FOOD from leaves to all parts).	Vascular bundles

Animal Tissues

Type	Function	Examples
Epithelial	COVERING and LINING	Skin, lining of mouth, blood vessels
Connective	SUPPORT and CONNECT	Bone, cartilage, blood, adipose (fat)
Muscular	MOVEMENT	Skeletal (voluntary), smooth (involuntary — intestines), cardiac (heart)
Nervous	TRANSMIT MESSAGES	Brain, spinal cord, nerves. Neurons = nerve cells.

2. Kingdom Classification (Whittaker's Five Kingdoms)

Kingdom	Cell Type	Nutrition	Examples
Monera	Prokaryotic (no nucleus)	Autotrophic or Heterotrophic	Bacteria, Cyanobacteria
Protista	Eukaryotic (has nucleus). Unicellular.	Autotrophic or Heterotrophic	Amoeba, Paramecium, Algae
Fungi	Eukaryotic. Multicellular (mostly). Cell wall of CHITIN.	Saprophytic (absorb from dead matter)	Mushroom, Yeast, Mould
Plantae	Eukaryotic. Multicellular. Cell wall of CELLULOSE.	Autotrophic (photosynthesis)	Moss, Fern, Mango, Rose
Animalia	Eukaryotic. Multicellular. NO cell wall.	Heterotrophic (ingest food)	Insects, Fish, Birds, Mammals

3. Plant Life — Photosynthesis and Respiration

Photosynthesis

Sunlight + 6CO₂ + 6H₂O → C₆H₁₂O₆ (glucose) + 6O₂

Occurs in CHLOROPLASTS (contains chlorophyll — the GREEN pigment)
'The most important chemical reaction on Earth. It produces FOOD and OXYGEN for nearly all life.'

Factors Affecting Photosynthesis

SUNLIGHT intensity. Carbon dioxide concentration. Water availability. Temperature.

Respiration in Plants

Plants BREATHE too! They take in OXYGEN and release CARBON DIOXIDE — through STOMATA (tiny pores in leaves) and LENTICELS (pores in stems).

4. Human Body — Nervous System

The Control Centre

The NERVOUS SYSTEM controls and coordinates EVERYTHING in your body — movement, senses, thoughts, emotions.

Structure

Central Nervous System (CNS) : Brain + Spinal Cord
Peripheral Nervous System (PNS) : Nerves connecting CNS to the rest of the body

The Neuron (Nerve Cell)

The functional unit. Receives signals through DENDRITES → cell body processes → sends signal along AXON → reaches next neuron or muscle/gland.

Reflex Action

A RAPID, AUTOMATIC response to a stimulus. Does NOT involve the brain (goes through the spinal cord only — to save TIME). Example: pulling your hand from a hot object.

Brain — Major Parts

Part	Function
Cerebrum	Thinking, memory, intelligence, voluntary movements
Cerebellum	Balance, coordination
Medulla Oblongata	Involuntary actions — heartbeat, breathing, blood pressure

5. Human Body — Excretory System

Why Excretion?

Your body produces WASTE — from the chemical reactions of life. This waste is TOXIC. It MUST be removed.

The Kidneys — The Filters

Two bean-shaped organs. FILTER the blood. Remove UREA (a nitrogenous waste from protein breakdown).
The filtered waste = URINE. Travels through URETERS → stored in the URINARY BLADDER → expelled through the URETHRA.

Other Excretory Organs

Skin: Excretes sweat (water + salts). Also helps regulate TEMPERATURE.
Lungs: Excrete CARBON DIOXIDE when we breathe out.
Liver: Breaks down proteins → produces UREA (which the kidneys filter).

6. Health and Hygiene

Communicable vs. Non-Communicable Diseases

Communicable: Spread from person to person. Common cold, flu, tuberculosis, COVID-19, malaria (vector: mosquito).
Non-communicable: Not spread. Diabetes, heart disease, cancer.

Prevention

Balanced DIET. Regular EXERCISE. Adequate SLEEP. Clean DRINKING WATER.
PERSONAL HYGIENE: Wash hands. Brush teeth.
VACCINATION: The most effective way to prevent many communicable diseases.

Key formulas & results

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Tissues, Classification, Nervous System, and Excretion

TISSUE: Group of SIMILAR CELLS working together for a SPECIFIC FUNCTION. PLANT TISSUES: MERISTEMATIC: actively dividing cells. Location: root tips, shoot tips (apical meristem), lateral meristem. Cells: small, thin-walled. PERMANENT — SIMPLE: Parenchyma (living, loosely packed — STORAGE, photosynthesis). Collenchyma (living, thickened walls — FLEXIBLE SUPPORT). Sclerenchyma (dead, thick lignified walls — STRENGTH: in nutshells, coconut husk). PERMANENT — COMPLEX: Xylem (dead cells — transports WATER + MINERALS up from roots). Phloem (living sieve tubes — transports FOOD from leaves). ANIMAL TISSUES: EPITHELIAL: covering and lining (skin, mouth lining, blood vessels). CONNECTIVE: support and connect (bone, cartilage, blood, adipose/fat). MUSCULAR: SKELETAL (voluntary, striated — attached to bones). SMOOTH (involuntary — intestines, blood vessels). CARDIAC (heart — involuntary, never tires). NERVOUS: transmit messages (neurons = nerve cells. Brain, spinal cord, nerves). FIVE KINGDOMS (Whittaker): MONERA (prokaryotic — no nucleus: bacteria, cyanobacteria). PROTISTA (eukaryotic, unicellular: Amoeba, Paramecium, algae). FUNGI (eukaryotic, mostly multicellular, cell wall of CHITIN, saprophytic: mushroom, yeast, mould). PLANTAE (eukaryotic, multicellular, cell wall of CELLULOSE, autotrophic: moss, fern, mango). ANIMALIA (eukaryotic, multicellular, NO cell wall, heterotrophic: insects, fish, birds, mammals). PHOTOSYNTHESIS: 6CO₂ + 6H₂O + Sunlight → C₆H₁₂O₆ + 6O₂. Site: CHLOROPLASTS. NERVOUS SYSTEM: CNS = Brain + Spinal Cord. PNS = nerves connecting CNS to rest of body. NEURON: DENDRITES receive signals → CELL BODY processes → AXON transmits to next neuron or muscle. REFLEX ACTION: RAPID, AUTOMATIC, does NOT involve brain. Stimulus → RECEPTOR → afferent nerve → SPINAL CORD → efferent nerve → EFFECTOR → Response. Faster than conscious control — essential for survival. BRAIN PARTS: CEREBRUM (largest part): thinking, memory, intelligence, voluntary movements, language. CEREBELLUM: BALANCE and COORDINATION (smooth movements). MEDULLA OBLONGATA: INVOLUNTARY functions (heartbeat, breathing, blood pressure, swallowing). EXCRETORY SYSTEM: Why: metabolic reactions produce TOXIC waste. KIDNEYS (2 bean-shaped): filter BLOOD, remove UREA (from protein breakdown). Filtered waste = URINE. Pathway: Kidneys → URETERS → URINARY BLADDER (storage) → URETHRA (expelled). OTHER EXCRETORY ORGANS: SKIN (sweat = water+salts; also temperature regulation). LUNGS (CO₂ when breathing out). LIVER (breaks down proteins → produces UREA for kidneys to filter).

ICSE CLASS 7 BIOLOGY KEY FACTS: (1) FUNGI cell wall = CHITIN (different from plant cellulose and bacterial peptidoglycan). (2) REFLEX ARC: goes through SPINAL CORD only, NOT the brain — this is the key feature that makes reflexes FAST (the signal doesn't have to travel all the way to the brain and back). (3) MEDULLA OBLONGATA controls HEARTBEAT and BREATHING — involuntary functions. An injury here can be fatal. (4) UREA is produced by the LIVER (from protein breakdown), then filtered and removed by the KIDNEYS. Both organs are involved in nitrogen excretion. (5) SCLERENCHYMA is DEAD at maturity — like xylem. Parenchyma and phloem sieve tubes are LIVING. (6) Smooth muscle in intestines = INVOLUNTARY (you can't control digestion by will). Skeletal muscle attached to bones = VOLUNTARY (you control walking/typing).

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Common mistakes & fixes

These are the exact errors that cost students marks in board exams. Read them once, save yourself the trouble.

WATCH OUT

✗ Saying reflex actions involve the brain or that fungi are plants

✓ TWO CORRECTIONS: (1) REFLEX ACTIONS: Reflex actions do NOT involve the brain. The neural pathway goes: Receptor → Afferent nerve → SPINAL CORD → Efferent nerve → Effector (muscle). The spinal cord processes the reflex WITHOUT waiting for the brain. The brain becomes aware AFTER the reflex happens. This is why reflexes are so FAST — no round trip to the brain. Example: Touching a hot stove — your hand withdraws BEFORE you feel pain (the pain sensation is processed by the brain slightly later). (2) FUNGI ≠ PLANTS: Plants: cell wall of CELLULOSE, make their own food by photosynthesis (autotrophic), green (have chlorophyll). Fungi: cell wall of CHITIN (same as insect exoskeleton), cannot photosynthesize, get food by breaking down dead matter (saprophytic/heterotrophic), no chlorophyll. Fungi are classified in a SEPARATE KINGDOM from plants.

Practice problems

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Q1MEDIUM· nervous-system-excretion

Distinguish between voluntary and involuntary actions, and give 2 examples each. Then explain the reflex arc with a specific example.

▶ Show solution

VOLUNTARY vs INVOLUNTARY ACTIONS: VOLUNTARY ACTIONS: Actions under CONSCIOUS CONTROL. The brain makes the decision. Examples: Writing (you choose what to write). Playing cricket (you choose when to swing). Walking (you decide where to go). Controlled by the CEREBRUM. INVOLUNTARY ACTIONS: Actions NOT under conscious control. Happen AUTOMATICALLY. Examples: Heartbeat (medulla oblongata controls this). Breathing at rest. Blinking. Digestion (peristalsis in intestines). Controlled by MEDULLA OBLONGATA (in brain) or the SPINAL CORD (for reflexes). REFLEX ARC — EXPLAINED WITH EXAMPLE: EXAMPLE: Touching a hot pan. STIMULUS: Heat from the pan. RECEPTOR: Sensory nerve endings in the skin of the finger receive the heat stimulus. AFFERENT NERVE: A sensory neuron carries the signal TO the spinal cord. SPINAL CORD: The signal is processed here WITHOUT involving the brain. The spinal cord generates a RESPONSE immediately. EFFERENT NERVE: A motor neuron carries the response signal FROM the spinal cord TO the effector. EFFECTOR: The muscle in the hand contracts. RESPONSE: The hand pulls AWAY from the hot pan. WHY IT'S IMPORTANT: The ENTIRE reflex happens in MILLISECONDS — before the brain even becomes aware of the pain. If the response had to travel to the brain and back, the hand would have sustained much more damage. Reflexes are PROTECTIVE, life-saving responses.

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