biology test

1. Characteristics of Life (MRS GREN)

All living things share these features:

• Movement – can move/change position.

• Respiration – release of energy from glucose.

• Sensitivity – respond to environment.

• Growth – permanent increase in size/cell number.

• Reproduction – make offspring.

• Excretion – remove waste (e.g., CO₂, urea).

• Nutrition – take in and use nutrients.

(Exam tip: photosynthesis is NOT in MRS GREN → not all organisms do it!)

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2. Classification & Organisation of Living Things

Levels of Organisation

Cell → Tissue → Organ → Organ system → Organism

Taxonomy Hierarchy

Kingdom → Phylum → Class → Order → Family → Genus → Species

Binomial nomenclature (Carl Linnaeus):

• 2-word Latin name: Genus species

• Genus = first name (capitalized)

• Species = second name (lowercase)

• Example: Lion = Panthera leo

Dichotomous Keys

• A series of “yes/no” or “either/or” choices that lead to identification.

Cladograms

• Diagrams that show evolutionary relationships (common ancestors, shared traits).

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3. The 5 Kingdoms

Prokaryotes (Monera/Bacteria)

• Unicellular.

• No nucleus (DNA is free in cytoplasm).

• No membrane-bound organelles.

• Cell wall made of peptidoglycan.

Protists

• Mostly unicellular eukaryotes.

• Some are plant-like (algae), some animal-like (amoeba).

Fungi

• Mostly multicellular (except yeast).

• Cell wall of chitin.

• No chloroplasts → heterotrophic (absorb food).

• Examples: mushrooms, yeast, mould.

Plants

• Multicellular.

• Cell wall of cellulose.

• Chloroplasts → photosynthesis.

• Store carbohydrates as starch.

Animals

• Multicellular.

• No cell wall.

• No chloroplasts.

• Store carbohydrates as glycogen.

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4. Plant Kingdom – Key Groups

Ferns

• Reproduce with spores, not seeds.

• Have vascular tissue (xylem & phloem).

• True roots, stems, and leaves.

Flowering Plants (Angiosperms)

Split into Monocots and Dicots:

Monocots

• 1 cotyledon (seed leaf).

• Parallel leaf veins.

• Flower parts in 3s.

• Fibrous roots.

Dicots

• 2 cotyledons.

• Branching/net-like veins.

• Flower parts in 4s or 5s.

• Taproot system.

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5. Sample Exam-Style Questions (with answers)

✅ Which characteristic is not shared by all living organisms? → Photosynthesis

✅ Feature in all vertebrates & arthropods? → Cells without cell walls

✅ Binomial of Okapia johnstoni – genus? → Okapia

✅ Features of monocots? → Parallel veins + flower parts in 3s

✅ Species definition → Organisms that can interbreed + produce fertile offspring

✅ Two closest related species: Commiphora africana & Commiphora angolensis

✅ Fungi vs Plants: fungi = chitin wall, no chloroplasts

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6. Quick Flash Facts

• Arthropods → exoskeleton, jointed legs, segmented body.

• Binomial system → universal, avoids confusion.

• Species → interbreeding + fertile offspring.

• Monocots vs Dicots → veins + seed leaves + flower part differences.

• 5 Kingdoms → Plants, Animals, Fungi, Protists, Prokaryotes.