Biology

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high importance~2 Q in Tier 14 formulas⚡ 12 shortcuts6 subtopics

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Classification, plants, hormones and animal facts

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⏱ 6 min read🧩 6 question types🎯 19 practice Q

The idea in one minute

Classification

Carolus Linnaeus — father of taxonomy; binomial nomenclature (genus + species, e.g. Homo sapiens).
R.H. Whittaker (1969) — five-kingdom classification: Monera (bacteria), Protista, Fungi, Plantae, Animalia.
Viruses are not placed in these kingdoms; they are 'living' only inside a host cell.

Scientific names (frequently asked)

Organism	Scientific name
Human	Homo sapiens
Mango	Mangifera indica
Tiger / Lion	Panthera tigris / Panthera leo
Peacock	Pavo cristatus
Neem	Azadirachta indica
Rice / Wheat	Oryza sativa / Triticum aestivum
Potato	Solanum tuberosum
Pea	Pisum sativum
Onion	Allium cepa
Banyan	Ficus benghalensis
Housefly	Musca domestica

Plant physiology

Photosynthesis occurs in chloroplasts using chlorophyll; the oxygen released comes from water.
Xylem carries water and minerals upward; phloem carries food (translocation).
Transpiration — loss of water through stomata.
Nitrogen fixation — Rhizobium bacteria in the root nodules of legumes (pulses); blue-green algae (e.g. Anabaena) in paddy fields.
Insectivorous plants: pitcher plant (Nepenthes), Venus flytrap, sundew — they grow in nitrogen-poor soil. Parasite: Cuscuta (amarbel).

Plant hormones

Hormone	Main role
Auxin	Cell elongation, apical dominance, phototropism, rooting
Gibberellin	Stem elongation, seed germination, fruit size
Cytokinin	Cell division, delays ageing of leaves
Abscisic acid (ABA)	'Stress hormone' — dormancy, closes stomata, leaf fall
Ethylene	Fruit ripening (the only gaseous hormone)

Edible parts

Plant	Edible part
Potato	Stem (tuber)
Ginger, turmeric	Stem (rhizome)
Onion	Bulb (fleshy leaf bases on a short stem)
Carrot, radish, sweet potato, beetroot	Root
Cauliflower	Inflorescence (flower)
Apple	Thalamus (false fruit)
Mango	Mesocarp
Coconut	Endosperm
Spinach, cabbage	Leaves

Animal facts

Largest animal: blue whale. Largest bird: ostrich. Egg-laying mammals: platypus, echidna. The only mammal that truly flies: bat.
Whales, dolphins and bats are mammals; fish breathe with gills; frogs are amphibians.
Cold-blooded: fish, amphibians, reptiles. Warm-blooded: birds, mammals.
Insects have 6 legs; spiders have 8 (arachnids, not insects). The earthworm is the 'farmer's friend'.

Classification — the ladder

Carolus Linnaeus, the father of taxonomy, gave binomial nomenclature (two-word scientific name: genus + species, in italics — Mangifera indica). R.H. Whittaker (1969) gave the five-kingdom classification: Monera, Protista, Fungi, Plantae, Animalia (earlier: two kingdoms, plants and animals). Plants divide into cryptogams (seedless — algae, fungi, bryophytes, pteridophytes) and phanerogams (seed plants — gymnosperms, naked seed; angiosperms, seed inside fruit). Monocots (wheat, rice, maize): one seed leaf, parallel leaf veins, fibrous roots. Dicots (mango, pea, gram): two seed leaves, reticulate veins, taproot.

Plant hormones

Auxin — cell elongation, bending to light (phototropism). Gibberellin — stem elongation, seed germination. Cytokinin — cell division, delays leaf ageing. Ethylene (gas) — fruit ripening. Abscisic acid — the stress hormone: closes stomata, promotes wilting and dormancy.

Photosynthesis and transport

Photosynthesis in the chloroplast (green pigment chlorophyll): 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ in sunlight. Leaves exchange gases through stomata; transpiration pulls water up the xylem (phloem carries food). Excess water vapour escapes mainly through the leaf's lower surface.

Edible parts — the exam favourite

Plant	Edible part
Carrot, radish, beetroot, turnip	Root
Potato, ginger, turmeric, onion (bulb), sugarcane	Stem (modified)
Cabbage, spinach, lettuce	Leaves
Cauliflower, broccoli	Flower
Tomato, brinjal, pumpkin, cucumber	Fruit
Groundnut, gram, mustard, rice, wheat	Seed
Apple, cashew	Fleshy thalamus (accessory fruit)

Reproduction and scientific names

Vegetative propagation: runners, bulbs, and human-made grafting, layering, cutting, tissue culture. Pollination agents: wind (maize, wheat — light dry pollen), water, insects (bright petals, nectar). Common scientific names: mango Mangifera indica, neem Azadirachta indica, banyan Ficus benghalensis, tamarind Tamarindus indica, potato Solanum tuberosum, rice Oryza sativa, tiger Panthera tigris, frog Rana tigrina.

Question types you will see

Each type: how to recognise it, the method step by step, and one question to try.

Type 1very common3 practice Q

Classification history and systems

How to spot it:

'Who gave binomial nomenclature / five-kingdom classification', 'which kingdom does a bacterium belong to', two-kingdom vs five-kingdom, cryptogam vs phanerogam.

Method

Linnaeus — binomial nomenclature, father of taxonomy (species plantarum, 1753). Whittaker (1969) — five kingdoms: Monera, Protista, Fungi, Plantae, Animalia.
Bacteria sit in Monera (prokaryotes); moulds and mushrooms in Fungi.
Cryptogams = seedless (algae to ferns); phanerogams = seed-bearing (gymnosperms naked seed, angiosperms covered).

Why it works:

one scientist = one system; the kingdom of bacteria is the standard trap.

Try this

The five-kingdom classification was proposed by —

Show solution

R.H. Whittaker (1969) — Monera, Protista, Fungi, Plantae, Animalia. Linnaeus earlier gave binomial nomenclature.

Type 2very common4 practice Q

Edible part of the plant

How to spot it:

'Potato is a modified…', 'carrot is which plant part', 'onion is a modified…', match-the-column of plants and their edible parts.

Method

Roots: carrot, radish, beetroot, turnip, sweet potato.
Stems: potato (tuber), ginger/turmeric (rhizome), onion/garlic (bulb), sugarcane.
Leaves: cabbage, spinach, lettuce. Flower: cauliflower, broccoli. Fruit: tomato, brinjal, pumpkin. Seed: groundnut, gram, mustard.
The double trap: sweet potato is a ROOT, ordinary potato a STEM; onion is a bulb (stem with fleshy leaves).

Why it works:

recall by family groups — roots cluster, stems cluster, one fruit list.

Try this

The potato we eat is a modified —

Show solution

Stem — an underground tuber with 'eyes' (buds). Sweet potato, despite the name, is a modified root.

Type 3very common3 practice Q

Plant hormones

How to spot it:

'Which hormone ripens fruits', 'which hormone causes bending towards light', 'stress hormone of plants', 'which hormone promotes cell division'.

Method

Auxin — elongation, phototropism (bending to light). Gibberellin — stem length, germination. Cytokinin — cell division, delays ageing.
Ethylene (a gas) — fruit ripening; abscisic acid — stress, stomatal closure, wilting.
Ripening = ethylene; bending = auxin; wilting = ABA — three fixed one-word answers.

Try this

The plant hormone responsible for fruit ripening is —

Show solution

Ethylene — the only gaseous plant hormone. Ripening bananas release it, so they can ripen other fruit kept nearby.

Type 4common3 practice Q

Photosynthesis and transport

How to spot it:

'Which gas is released in photosynthesis', 'which pigment absorbs light', 'xylem carries…', 'stomata are found on…', photosynthesis word equation.

Method

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ — inputs CO₂ + water, outputs glucose + oxygen; pigment = chlorophyll in chloroplasts.
Xylem carries water/minerals up; phloem carries food both ways.
Stomata (mostly on the leaf's lower surface) do gas exchange and transpiration.

Try this

In photosynthesis, plants release —

Show solution

Oxygen, splitting water in the chloroplast: 6CO₂ + 6H₂O → glucose + 6O₂ in sunlight.

Type 5common2 practice Q

Monocot vs dicot and reproduction

How to spot it:

'Which is a monocot', 'parallel venation indicates…', 'pollination by insects / wind', 'grafting is a method of…', number of cotyledons.

Method

Monocots — wheat, rice, maize, onion: one cotyledon, parallel veins, fibrous roots. Dicots — mango, pea, gram, sunflower: two cotyledons, reticulate veins, taproot.
Insect pollination: bright petals + nectar + scent (mustard, rose). Wind: light dry pollen (maize, wheat).
Grafting, layering, cutting, tissue culture = vegetative (asexual) propagation.

Try this

Which of these shows parallel venation (a monocot)?

Show solution

Maize/wheat/rice/onion — monocots have parallel veins and fibrous roots; mango and pea are dicots with net-like veins.

Type 6common2 practice Q

Scientific names and firsts

How to spot it:

'The scientific name of mango / neem / rice', match-the-column of plants and binomials, father-of-taxonomy questions.

Method

Mango Mangifera indica; neem Azadirachta indica; banyan Ficus benghalensis; tamarind Tamarindus indica.
Potato Solanum tuberosum; rice Oryza sativa; wheat Triticum aestivum; cat Felis catus; tiger Panthera tigris.
First word = genus (capital), second = species (small), both italic — the binomial rule of Linnaeus.

Try this

The scientific name of mango is —

Show solution

Mangifera indica — genus Mangifera, species indica. Neem is Azadirachta indica.

Formula sheet

Photosynthesis

6CO_2 + 6H_2O \xrightarrow[\text{chlorophyll}]{\text{sunlight}} C_6H_{12}O_6 + 6O_2

O₂ comes from water

Aerobic respiration

C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{energy (ATP)}

Shortcuts that save time

⚡ Underground but not a root

Potato, ginger, turmeric, onion grow underground but are stems (they have nodes/buds or 'eyes'). Carrot, radish, sweet potato, beetroot are true roots.

Example

The edible part of ginger is?

Show solution

A modified stem (rhizome).

⚡ Five kingdoms: 'My Pet Fish Plays Alone'

Monera, Protista, Fungi, Plantae, Animalia — Whittaker, 1969.

Mistakes to avoid

Where most students lose marks on this subtopic.

Mistake 01

Calling sweet potato a stem and potato a root — it is the other way round.

Mistake 02

Saying the oxygen from photosynthesis comes from CO₂ — it comes from water.

Mistake 03

Calling the bat a bird or the whale a fish — both are mammals.

Quick revision

Read this the night before the exam.

Linnaeus = binomial nomenclature, father of taxonomy; Whittaker = 5 kingdoms (1969).
Monocot: one cotyledon, parallel veins; dicot: two, reticulate veins.
Auxin–elongation/phototropism; gibberellin–stem; cytokinin–division; ethylene–ripening; ABA–stress.
Carrot root, potato/ginger/onion stem, cabbage leaf, cauliflower flower, tomato fruit, groundnut seed.
Photosynthesis: 6CO₂ + 6H₂O → glucose + 6O₂; stomata = gas exchange; xylem water, phloem food.

Practice: 19 questions

Sets of 10, mixed across the question types above. Every answer has a step-by-step explanation.

Topic test · 10 questions

Suggested time 3 min · wrong answers go to your mistake notebook automatically.

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