Edexcel iGCSE Biology-1.2 Common Features of Eukaryotic Organisms- Study Notes- New Syllabus
Edexcel iGCSE Biology-1.2 Common Features of Eukaryotic Organisms- Study Notes- New syllabus
Edexcel iGCSE Biology-1.2 Common Features of Eukaryotic Organisms- Study Notes -Edexcel iGCSE Biology – per latest Syllabus.
Key Concepts:
1.2 Describe the common features shown by eukaryotic organisms: plants, animals, fungi and protoctists
- Plants: These are multicellular organisms; their cells contain chloroplasts and are able to carry out photosynthesis; their cells have cellulose cell walls; they store carbohydrates as starch or sucrose. Examples include flowering plants, such as a cereal (for example, maize), and a herbaceous legume (for example, peas or beans).
- Animals: These are multicellular organisms; their cells do not contain chloroplasts and are not able to carry out photosynthesis; they have no cell walls; they usually have nervous coordination and are able to move from one place to another; they often store carbohydrate as glycogen. Examples include mammals (for example, humans) and insects (for example, housefly and mosquito).
- Fungi: These are organisms that are not able to carry out photosynthesis; their body is usually organized into a mycelium made from thread-like structures called hyphae, which contain many nuclei; some examples are single-celled; their cells have walls made of chitin; they feed by extracellular secretion of digestive enzymes onto food material and absorption of the organic products; this is known as saprotrophic nutrition; they may store carbohydrate as glycogen. Examples include Mucor, which has the typical fungal hyphal structure, and yeast, which is single-celled.
- Protoctists: These are microscopic single-celled organisms. Some, like Amoeba, that live in pond water, have features like an animal cell, while others, like Chlorella, have chloroplasts and are more like plants. A pathogenic example is Plasmodium, responsible for causing malaria.
Variety of Living Organisms
📝 Introduction
Eukaryotic organisms = organisms whose cells have a nucleus enclosed by a membrane. They also usually contain membrane-bound organelles (like mitochondria, chloroplasts, vacuoles).
The four eukaryotic groups listed below:
🌱 Plants
- Multicellular organisms.
- Contain chloroplasts → carry out photosynthesis.
- Cells have cellulose cell walls.
- Store carbohydrates as starch or sucrose.
- Usually have roots, stems, leaves.
🔹 Examples:
Cereal → Maize
Herbaceous legume → Peas, Beans
🦁 Animals
- Multicellular organisms.
- No chloroplasts → cannot photosynthesise.
- No cell walls.
- Usually have nervous coordination → can respond quickly to surroundings.
- Able to move from place to place.
- Store carbohydrate as glycogen.
🔹 Examples:
Mammals → Humans
Insects → Housefly, Mosquito
🍄 Fungi
- Do not photosynthesise.
- Body often organised into a mycelium (network of thread-like structures = hyphae).
- Hyphae contain many nuclei.
- Some fungi are single-celled (e.g., yeast).
- Cell walls made of chitin.
- Nutrition: saprotrophic → secrete enzymes onto food, digest externally, absorb organic products.
- Store carbohydrate as glycogen.
🔹 Examples:
Mucor → typical hyphal structure.
Yeast → single-celled fungus.
🦠 Protoctists
- Mostly microscopic, single-celled organisms.
- Very diverse group:
- Some act like animal cells → e.g., Amoeba (lives in pond water).
- Some act like plant cells → e.g., Chlorella (has chloroplasts).
- Some are pathogenic (disease-causing).
🔹 Examples:
Amoeba → animal-like.
Chlorella → plant-like.
Plasmodium → pathogenic protoctist that causes malaria.
📊 Summary Table – Features of Eukaryotic Groups
| Group | Cell Type | Key Features | Storage Form | Examples |
|---|---|---|---|---|
| Plants | Multicellular | Chloroplasts, cellulose cell walls, photosynthesis | Starch / Sucrose | Maize, Peas |
| Animals | Multicellular | No chloroplasts, no cell walls, nervous coordination, movement | Glycogen | Humans, Mosquito |
| Fungi | Multi- or unicellular | No photosynthesis, hyphae (multi-nucleate), chitin walls, saprotrophic feeding | Glycogen | Mucor, Yeast |
| Protoctists | Mostly single-celled | Very mixed group: some animal-like, some plant-like | Varies | Amoeba, Chlorella, Plasmodium |
⚡ Quick Recap
Plants → Multicellular, photosynthesis, cellulose walls, starch/sucrose storage.
Animals → Multicellular, no chloroplasts/walls, nervous coordination, glycogen storage.
Fungi → No photosynthesis, chitin walls, hyphae/mycelium, saprotrophic, glycogen storage.
Protoctists → Single-celled, mixed features, some pathogenic (Plasmodium causes malaria).
👉 All are eukaryotic (cells with nuclei + organelles).
Plants → Multicellular, photosynthesis, cellulose walls, starch/sucrose storage.
Animals → Multicellular, no chloroplasts/walls, nervous coordination, glycogen storage.
Fungi → No photosynthesis, chitin walls, hyphae/mycelium, saprotrophic, glycogen storage.
Protoctists → Single-celled, mixed features, some pathogenic (Plasmodium causes malaria).
👉 All are eukaryotic (cells with nuclei + organelles).