Key Concepts: All living organisms share eight characteristics. Organisms are classified as eukaryotes (plants, animals, fungi, protoctists) or prokaryotes (bacteria). Pathogens are disease-causing agents, including viruses which are not living cells.
Section A — Characteristics of Living Organisms
1. List all eight characteristics of living organisms. [8]
2. Match each description to the correct characteristic. [8]
Characteristics: nutrition, respiration, excretion, response, movement, homeostasis, reproduction, growth
a) Releasing energy from food molecules inside cells
b) Removing metabolic waste products such as CO₂ and urea
c) Detecting and reacting to changes in the environment
d) Maintaining stable internal conditions (e.g. temperature, water balance)
e) Taking in materials needed for energy, growth, or repair
f) Producing offspring to continue the species
g) An increase in size and complexity over time
h) Changing position or location, or moving parts of the body
3. Name the characteristic of living organisms shown in each scenario. [6]
a) A plant bends towards a light source
b) A rabbit produces young
c) A person sweats to cool down on a hot day
d) Glucose is broken down in muscle cells during exercise
e) Carbon dioxide is exhaled by the lungs
f) A seedling increases in height over several weeks
Section B — Eukaryotic Organisms
4. Complete the table for the four groups of eukaryotic organisms. [8]
| Group |
Key features (at least two) |
Named example |
| Plants | | |
| Animals | | |
| Fungi | | |
| Protoctists | | |
5. Classify each organism as plant, animal, fungus, or protoctist. [5]
| Organism | Group |
|---|
| Chlorella | |
| Mucor | |
| Amoeba | |
| Maize | |
| Human | |
Section C — Prokaryotes (Bacteria)
6. State four structural features of a bacterium. [4]
7. State two differences between prokaryotic and eukaryotic cells. [2]
Section D — Pathogens and Viruses
8. Define the term pathogen and give two examples. [3]
9. State four features of viruses. [4]
10. State two differences between viruses and bacteria. [2]
11. Explain why viruses are not considered to be living organisms. [2]
Total marks: 52
Mark Scheme
1. Nutrition, respiration, excretion, response, movement, homeostasis (control of internal conditions), reproduction, growth and development [8 — 1 per characteristic]
2. a) Respiration b) Excretion c) Response d) Homeostasis e) Nutrition f) Reproduction g) Growth h) Movement [8]
3. a) Response b) Reproduction c) Homeostasis d) Respiration e) Excretion f) Growth [6]
4. Plants: multicellular, chloroplasts for photosynthesis, cellulose cell wall, store starch/sucrose; Animals: multicellular, no chloroplasts, no cell wall, glycogen storage; Fungi: mycelium of hyphae, chitin cell wall, saprotrophic nutrition, glycogen; Protoctists: mostly single-celled, some plant-like (e.g. Chlorella), some animal-like (e.g. Amoeba) [8]
5. Chlorella — protoctist; Mucor — fungus; Amoeba — protoctist; Maize — plant; Human — animal [5]
6. Any four: cell wall (not cellulose), cell membrane, cytoplasm, circular DNA (no nucleus), plasmids, flagellum/pili (any four) [4]
7. Any two: prokaryotes have no membrane-bound nucleus; prokaryotes have circular DNA and plasmids; prokaryotes smaller; prokaryotes have no membrane-bound organelles [2]
8. A pathogen is an organism (or virus) that causes disease [1]; examples: Plasmodium (malaria), influenza virus, Salmonella bacteria, HIV (any two) [2]
9. Any four: not made of cells; smaller than bacteria; protein coat (capsid); contain DNA or RNA (not both); can only reproduce inside a host cell; no cytoplasm or organelles [4]
10. Any two: viruses are not cells and lack organelles/cytoplasm; viruses can only reproduce inside host cells whereas bacteria reproduce independently; bacteria have a cell wall and membrane; bacteria are larger [2]
11. Viruses cannot carry out all the characteristics of life independently / cannot reproduce outside a host cell; they have no metabolism (respiration, nutrition, excretion) of their own [2]