Free ZIMSEC O-Level Revision

Biology Revision & Mock Test

Study the core Biology topics, practise original questions, receive an instant mark, read corrections and see which topics need more work.

12 topic guides · 20-question mock · instant corrections

Practice notice: Original New Horizon practice questions – not an official ZIMSEC examination paper.

Biology topic guides

1. Introduction, Safety and Careers

Learn

Use risk assessments, wear suitable PPE, label materials and follow laboratory instructions. Biology careers include medicine, agriculture, ecology and biotechnology.

Exam focus: Never taste chemicals or handle specimens without permission.

2. Chemicals of Life

Learn

Carbohydrates supply energy, proteins support growth and repair, and lipids store energy. Iodine tests for starch, Biuret tests for protein and ethanol emulsion tests for lipids.

Exam focus: Record both the reagent and the positive colour result.

3. Cells and Cellular Activities

Learn

Cells contain specialised structures. Diffusion moves particles down a concentration gradient; osmosis is water movement through a partially permeable membrane; active transport requires energy.

Exam focus: Do not describe osmosis as movement of any particle.

4. Enzymes

Learn

Enzymes are biological catalysts with specific active sites. Temperature and pH affect reaction rate; extreme conditions can denature an enzyme.

Exam focus: An enzyme is not used up in the reaction.

5. Plant Science

Learn

Plants photosynthesise, absorb mineral ions, transport water in xylem and sugars in phloem, and respond to stimuli. Transpiration is water loss from leaves.

Exam focus: Balance photosynthesis using carbon dioxide, water, glucose and oxygen.

6. Animal Science

Learn

Animals obtain nutrients, exchange gases, transport substances, coordinate responses, reproduce and maintain stable internal conditions.

Exam focus: Link organ structure to its function in explanations.

7. Respiration

Learn

Aerobic respiration releases energy from glucose using oxygen. Anaerobic respiration releases less energy; yeast produces ethanol and carbon dioxide.

Exam focus: Respiration occurs in cells and is not the same as breathing.

8. Microbiology and Biotechnology

Learn

Microorganisms can cause disease or be useful in food production, fermentation and biotechnology. Hygiene and controlled conditions reduce contamination.

Exam focus: Antibiotics treat susceptible bacteria, not viruses.

9. Genetics

Learn

DNA forms genes on chromosomes. Alleles are alternative forms of a gene; dominant alleles are expressed in a heterozygote. Variation may be genetic or environmental.

Exam focus: Use genetic diagrams carefully and label gametes and offspring.

10. Biodiversity

Learn

Classification groups organisms by shared features. Binomial names have genus and species. Conservation protects species, habitats and genetic diversity.

Exam focus: The genus name begins with a capital letter; species is lower case.

11. Ecosystems

Learn

Food chains show energy transfer. Food webs, nutrient cycles, population interactions and human activities shape ecosystems.

Exam focus: Arrows in a food chain point in the direction of energy transfer.

12. Health and Disease

Learn

Communicable diseases spread between organisms; non-communicable diseases do not. Immunity, vaccination, sanitation and vector control reduce disease.

Exam focus: Use evidence-based prevention and avoid stigma when discussing disease.

Biology mock test

Choose one answer for each question, then submit. Unanswered questions are marked incorrect so your result reflects exam readiness.

1. Which action is safest during a laboratory investigation?

Taste an unknown solution Wear suitable eye protection Run between benches Return unused chemicals to stock

2. A blue-black colour after adding iodine shows the presence of:

protein fat starch vitamin C

3. A lilac or purple Biuret result shows the presence of:

protein starch reducing sugar water

4. Which structure controls movement of substances into and out of a cell?

cell membrane nucleus cell wall chloroplast

5. Osmosis is the movement of:

solute from low to high concentration water through a partially permeable membrane oxygen using energy glucose through xylem

6. Which pair commonly affects enzyme activity?

light and sound temperature and pH mass and weight colour and volume

7. Which substances are raw materials for photosynthesis?

glucose and oxygen carbon dioxide and water protein and minerals oxygen and water

8. What is the main function of xylem?

transport water and mineral ions transport nerve impulses make pollen digest starch

9. Arteries generally carry blood:

towards the heart away from the heart only without oxygen only to the lungs

10. Which feature makes alveoli effective for gas exchange?

thick dry walls small surface area thin moist walls and rich blood supply no capillaries

11. Aerobic respiration requires:

oxygen ethanol chlorophyll urea

12. Anaerobic respiration in yeast produces:

lactic acid only ethanol and carbon dioxide water and oxygen protein and starch

13. Why do antibiotics not cure viral infections?

Viruses are too large Antibiotics target bacterial processes Viruses contain chlorophyll Antibiotics are nutrients

14. Which microorganism is used to make bread rise?

yeast Plasmodium amoeba moss

15. A gene is best described as:

a section of DNA influencing a characteristic an entire organism a type of protein food a cell membrane

16. A dominant allele is expressed in:

only a homozygous recessive organism a heterozygote only gametes every species

17. A binomial scientific name contains:

family and kingdom genus and species class and order habitat and diet

18. In a food chain, arrows show the direction of:

water flow energy transfer animal movement wind

19. Vaccination helps protect people mainly by:

creating immune memory removing all microbes instantly replacing red blood cells stopping respiration

20. Which measure directly reduces malaria transmission?

sharing drinking cups using insecticide-treated mosquito nets taking antibiotics for every fever avoiding vegetables

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