2.3Organisation of the Organism
Levels of organisation — Cambridge IGCSE Biology 0610 Revision Notes & Topical Questions
5 min read 8 parts Lesson 4 of 4 2 quizzes
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Lesson summary
2.3 Levels of organisation — IGCSE BIOLOGY notes: Define cells, tissues, organs and organ systems and identify them in animals and plants.LevelDescriptionCellBasic functional and structural unit of all living organismsTissueGroup of cells of similar structure working together to …
- Palisade mesophyll cell
- Spongy mesophyll layer
- Tissue rule
- Shoot system
- Root system
- Magnification
Part 1 of 6The levels of organisation
| Level | Description |
|---|---|
| Cell | Basic functional and structural unit of all living organisms |
| Tissue | Group of cells of similar structure working together to perform the same function |
| Organ | Different tissues working together to perform specific functions |
| Organ system | Group of organs with related functions working together to perform body functions |
| Organism | All the organ systems working together |
Part 2 of 6Definitions to learn
Definitions to learn
Tissue
Tissue a group of cells of similar structure working together to perform the same function.
Organ
Organ made from different tissues working together to perform specific functions.
Organ system
Organ system a group of organs with related functions, working together to perform body functions.
Part 3 of 6Animal organ systems
| System | Organs | Tissue examples |
|---|---|---|
| Digestive | Oesophagus, stomach, small intestine, large intestine | Muscle, connective, nerve, epithelial |
| Circulatory | Heart, veins, arteries | Muscle, connective, nerve, epithelial |
| Respiratory | Trachea, bronchi, lungs | Muscle, epithelial, connective |
| Excretory | Kidney, skin, lungs | Epithelial, nerve, muscle |
| Nervous | Brain, spinal cord | Nerve, connective, muscle |
| Reproductive | Ovary, cervix, uterus, vagina, testes, penis | Muscle, connective, nerve, epithelial, erectile |
Part 4 of 6Plant organ systems
| System | Organs | Tissue examples |
|---|---|---|
| Shoot system | Leaf, stem, flower, fruit | Epidermis, mesophyll, xylem, phloem |
| Root system | Root, tuber | Xylem, phloem, ground tissue |
Part 5 of 6Identifying the level in a leaf
Leaf
- An organ, made of several different tissues.
Palisade mesophyll cell
- A single specialised cell.
Spongy mesophyll layer
- A tissue, because it is made of one type of cell.
Tissue rule
- A tissue is always made of only one type of cell.
Part 6 of 6More from the specification
Magnification
- Magnification image size divided by actual size, so actual size equals image size divided by magnification.
Units
- Units convert between millimetres, micrometres and nanometres when calculating sizes.
Cell structure
- Cell structure the nucleus holds DNA, the cytoplasm contains enzymes, and the cell membrane controls entry.
Microscope use
- Microscope use light microscopes show a limited resolution, while electron microscopes show organelles in detail.
Levels of organisation
- Levels of organisation cells form tissues, tissues form organs, and organs form organ systems.
Chloroplast
- The organelle of photosynthesis.
Photosynthesis
- The process by which plants make carbohydrates from raw materials using energy from light.
Cellulose
- A structural polysaccharide of β-glucose.
Ribosome
- The site where proteins are made.
Mitochondria
- Organelles where most aerobic respiration takes place.
Light microscope
- Microscope using light, magnifying up to about x1500.
Electron microscope
- A microscope powerful enough to show objects as small as a virus.
Endoplasmic reticulum
- Rough and smooth (lipids, detoxification).
- (ribosomes, proteins)
Magnification
- How many times larger the image is than the actual object; image size ÷ actual size, with no units.
Cytoplasm
- The jelly in which the cell's chemical reactions happen.
Nucleus
- The part of the cell that controls its activities.
Bacteria
- Single-celled microorganisms, much smaller than plant or animal cells.
Key terms
| Term | Meaning |
|---|---|
| Cell | The basic functional and structural unit of all living organisms. |
| Tissue | A group of cells of similar structure that perform the same function. |
| Organ | A structure of different tissues working together for specific functions. |
| Organ system | A group of organs with related functions working together. |
| Shoot system | The leaves, stem, flowers and fruit of a plant. |
| Root system | The roots and tubers of a plant. |
Avoid these mistakes
1
Calling a tissue a mixture of cell types — a tissue is made of only one type of cell.
2
Confusing a tissue with an organ — an organ contains several different tissues.
3
Saying an organ system is one organ — it is a group of organs with related functions.
4
Listing the leaf as a tissue — the leaf is an organ.
Marked practiceQuizzes for this lesson
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