Basics of Plant and Animal Kingdom
Basics of Plant and Animal Kingdom
This topic covers the cell, photosynthesis, plant transport and simple classification. Expect 1 to 2 questions in the science block. Because you will be teaching this exact content to classes 6 to 8, the examiner assumes you can state each process precisely rather than approximately.
The Cell
The cell is the structural and functional unit of life. It was discovered by Robert Hooke in 1665 in a slice of cork.
| Feature | Plant cell | Animal cell |
|---|---|---|
| Cell wall | Present | Absent |
| Chloroplast | Present | Absent |
| Vacuole | Large, central | Small or absent |
| Shape | Fixed, rectangular | Irregular, rounded |
Two organelles are asked by nickname: the mitochondrion is the powerhouse of the cell, and the nucleus is its control centre.
Photosynthesis
Green plants make their own food using sunlight, so they are called autotrophs. The process happens in the chloroplast, where the green pigment chlorophyll captures light.
Carbon dioxide + Water —(sunlight, chlorophyll)→ Glucose + Oxygen
Note the direction: photosynthesis takes in carbon dioxide and releases oxygen, while respiration does the reverse. Photosynthesis needs light; respiration goes on day and night.
✗ Plants respire only at night and photosynthesise only in the day | ✓ Photosynthesis needs light, but respiration continues day and night
Transport in Plants
| Tissue | Carries | Direction |
|---|---|---|
| Xylem | Water and minerals | Roots upward |
| Phloem | Prepared food | Both directions |
A simple memory hook: xylem and water both relate to the upward pull from the roots, while phloem carries food. Transpiration is the loss of water vapour through stomata on the leaf, and it helps pull water up the xylem.
✗ Phloem carries water from the roots | ✓ Xylem carries water; phloem carries food
Simple Classification
R. H. Whittaker's five-kingdom classification divides living things into Monera, Protista, Fungi, Plantae and Animalia. Within animals, the basic split is between vertebrates, which have a backbone, and invertebrates, which do not.
- Fish, amphibians, reptiles, birds and mammals are the five vertebrate classes.
- Mammals give birth to young ones and feed them milk; the bat is a flying mammal and the whale an aquatic one.
- Insects, worms and molluscs are invertebrates.
- Fungi and bacteria act mainly as decomposers, returning nutrients to the soil.
जाइलम पानी ऊपर ले जाता है, फ्लोएम भोजन — दोनों को उलटा मत दीजिए।
TRE pointer: The xylem-phloem swap and the day-night respiration myth are the two errors that cost candidates marks here every single time. Because this is middle-stage content you will teach yourself, expect the paper to ask the photosynthesis equation in the correct direction, including which gas is taken in and which released. With five options and −1/3 negative marking, a reversed equation is an avoidable loss.
60-Second Recap
- Cell discovered by Robert Hooke in 1665; mitochondrion is the powerhouse, nucleus the control centre.
- Plant cell has a cell wall, chloroplast and a large vacuole; animal cell does not.
- Photosynthesis takes in carbon dioxide and releases oxygen, in the chloroplast.
- Respiration happens day and night; photosynthesis needs light.
- Xylem carries water upward, phloem carries food both ways; transpiration occurs through stomata.
- Whittaker's five kingdoms: Monera, Protista, Fungi, Plantae, Animalia.
Frequently Asked Questions
What is the difference between xylem and phloem?
Xylem conducts water and dissolved minerals from the roots upward to the rest of the plant. Phloem transports the food prepared in the leaves and can move it in both directions. Reversing these two is the most frequent mistake in plant biology questions.
Do plants respire at night only?
No. Respiration continues in plants throughout the day and night, exactly as it does in animals. Photosynthesis is the process that requires sunlight and therefore stops at night. During the day photosynthesis dominates, which is why plants appear to release oxygen overall.
Who discovered the cell?
Robert Hooke, in 1665, while examining a thin slice of cork under his microscope. He saw box-like compartments and named them cells. Anton van Leeuwenhoek later observed living cells, and questions sometimes offer both names to test the distinction.
What are the five kingdoms of classification?
Monera, Protista, Fungi, Plantae and Animalia, proposed by R. H. Whittaker. Monera covers bacteria and other organisms without a true nucleus, Protista covers single-celled organisms with one, and the remaining three cover fungi, plants and animals respectively.