WASSCE 2019 Biology Questions and Answers – Set 3
50 Fresh Solved Biology Questions + 100 Biology MCQs with Answers, Explanations and Topic Analysis
Biology Practice Set 3
This Biology Set 3 has been designed as a large examination-style revision resource. It contains fifty structured questions followed by one hundred multiple-choice questions.
The questions cover a broad range of Biology areas including cell organisation, biomolecules, enzymes, plant physiology, human physiology, reproduction, genetics, ecology, microorganisms, evolution and practical Biology.
Every structured question is followed by a direct answer, a short explanation and an individual analysis showing the topic, chapter, skill and estimated difficulty.
Section A — 50 Solved Biology Questions
Answer
Cell → Tissue → Organ → Organ system.
Explanation
Cells are basic living units. Similar cells may form tissues, different tissues combine to form organs, and organs work together as organ systems.
Question Analysis
Answer
- Proteins are used for growth and repair of tissues.
- Many enzymes are proteins.
- Some proteins form structural components of cells.
- Some proteins have transport or defence functions.
Explanation
Proteins have many different functions because their structures allow them to perform specialised roles. Their amino-acid sequences determine their three-dimensional structures and biological properties.
Question Analysis
Answer
Carbohydrates provide an important source of energy and can also serve as storage or structural materials in organisms.
Explanation
Glucose can be used during respiration to release energy. Plants store carbohydrates mainly as starch, while cellulose is an important structural carbohydrate in plant cell walls.
Question Analysis
Answer
- They provide a concentrated energy store.
- They form important components of cell membranes.
- Body fat can provide insulation and protection.
Explanation
Lipids are energy-rich molecules. Certain lipids are major components of cell membranes, while stored fat can help with thermal insulation and protection of organs.
Question Analysis
Answer
Water acts as a solvent and transport medium, participates in many biochemical reactions and helps regulate temperature.
Explanation
Many substances dissolve in water, allowing them to be transported and react within cells. Water also has useful thermal properties that help organisms maintain suitable temperatures.
Question Analysis
Answer
The active site has a particular shape and chemical environment that allows specific substrate molecules to bind effectively.
Explanation
The interaction between enzyme and substrate depends on complementary structural and chemical features. Changes to the active site can reduce enzyme activity.
Question Analysis
Answer
Enzyme inhibition is the reduction of enzyme activity caused by a substance that interferes with the enzyme or its interaction with the substrate.
Explanation
Some inhibitors bind to an enzyme and prevent normal substrate binding or alter enzyme activity. The effect depends on the type and concentration of the inhibitor.
Question Analysis
Answer
- It separates the cell contents from the surrounding environment.
- It controls movement of many substances into and out of the cell.
- It contains proteins involved in cell signalling and transport.
Explanation
The membrane is selectively permeable. Its phospholipid bilayer and associated proteins allow cells to regulate their internal conditions.
Question Analysis
Answer
Active transport moves substances against a concentration gradient and therefore requires energy, usually supplied by ATP.
Explanation
Transport proteins use cellular energy to move selected substances from a lower concentration to a higher concentration. This differs from passive processes such as diffusion.
Question Analysis
Answer
Glucose + oxygen → carbon dioxide + water + energy.
Explanation
Aerobic respiration is a controlled series of reactions that releases usable energy from organic molecules in the presence of oxygen.
Question Analysis
Answer
Anaerobic respiration is the release of energy from organic molecules without using oxygen.
Explanation
Anaerobic pathways release less energy per glucose molecule than aerobic respiration. Different organisms produce different end products.
Question Analysis
Answer
- They have a large surface area.
- Their walls are very thin.
- They have a rich blood supply.
- Ventilation helps maintain concentration gradients.
Explanation
Efficient gas exchange requires a large area, short diffusion distance and a maintained concentration gradient. Blood flow and ventilation help maintain favourable gradients for oxygen and carbon dioxide movement.
Question Analysis
Answer
During inhalation, the diaphragm contracts and becomes flatter. This increases the volume of the thoracic cavity and helps lower pressure inside the lungs, allowing air to enter.
Explanation
Ventilation depends on pressure differences. Expansion of the thoracic cavity reduces pressure within the lungs relative to atmospheric pressure.
Question Analysis
Answer
Haemoglobin binds oxygen and allows red blood cells to transport substantial amounts of oxygen from the lungs to body tissues.
Explanation
Oxygen has limited solubility in plasma. Haemoglobin increases the blood’s oxygen-carrying capacity and can release oxygen where it is needed.
Question Analysis
Answer
Blood clotting helps reduce blood loss and contributes to sealing damaged blood vessels, while also helping protect the body from entry of pathogens.
Explanation
Platelets and clotting proteins participate in a cascade that produces a clot. The resulting barrier supports healing and limits continued bleeding.
Question Analysis
Answer
- Urea
- Excess water
- Excess mineral ions
Explanation
The kidneys filter blood and regulate the amounts of water and dissolved substances in body fluids. Urea is produced from the metabolism of excess amino acids and must be excreted.
Question Analysis
Answer
Urea is formed mainly in the liver during the breakdown of excess amino acids. It must be excreted because excessive accumulation of nitrogenous waste can be harmful.
Explanation
Amino acids cannot be stored in the same way as carbohydrate or fat. Excess amino acids are deaminated, producing ammonia, which is converted into the less toxic compound urea for excretion.
Question Analysis
Answer
Water balance helps maintain suitable conditions for cellular reactions, blood volume and the functioning of tissues.
Explanation
Cells depend on an appropriate water potential. Excessive water loss or gain can disrupt cell function and the composition of body fluids.
Question Analysis
Answer
Sweat production increases. Evaporation of sweat from the skin removes thermal energy and helps cool the body.
Explanation
The body uses several mechanisms to regulate temperature. Evaporation is effective because energy is required to change liquid water into water vapour.
Question Analysis
Answer
Cells require glucose for respiration, but excessive or insufficient concentrations can disturb normal body function. Regulation maintains a suitable level for metabolism.
Explanation
Hormonal control involving insulin and glucagon helps maintain blood glucose within an appropriate range. This is an example of homeostasis.
Question Analysis
Answer
A hormone is a chemical messenger produced by an endocrine gland or other specialised tissue and transported to target cells where it produces a specific effect.
Explanation
Hormones coordinate slower, longer-lasting processes such as growth, reproduction and metabolic regulation. Only cells with suitable receptors respond to a particular hormone.
Question Analysis
Answer
Phototropism is the directional growth response of a plant organ to light.
Explanation
Shoots commonly show positive phototropism, growing towards a light source. Hormonal redistribution, particularly involving auxin, contributes to the growth response.
Question Analysis
Answer
Roots generally show positive gravitropism, meaning they grow in the direction of gravity.
Explanation
Gravity provides directional information to growing roots. Hormonal responses alter cell elongation and contribute to the bending of the root.
Question Analysis
Answer
- Adequate water
- Suitable temperature
- Oxygen for respiration
Explanation
Water activates metabolic processes and allows tissues to swell. Suitable temperature supports enzyme activity, while oxygen is required for aerobic respiration in most germinating seeds.
Question Analysis
Answer
The cotyledon can store food reserves or absorb and transfer nutrients to the developing embryo, depending on the plant species.
Explanation
During early growth, the embryo may depend on stored nutrients before it becomes capable of producing enough food by photosynthesis.
Question Analysis
Answer
Translocation is the movement of organic assimilates, especially sucrose, through the phloem from sources to sinks.
Explanation
Leaves can act as sources when they produce sugars by photosynthesis. Growing roots, fruits, seeds and other tissues can act as sinks requiring imported organic nutrients.
Question Analysis
Answer
Stomata allow gaseous exchange between the leaf and the atmosphere and provide a route for carbon dioxide entry and water vapour loss.
Explanation
Stomatal pores can open and close as conditions change. This helps balance the need for carbon dioxide with the need to limit excessive water loss.
Question Analysis
Answer
Carbon dioxide + water → glucose + oxygen, in the presence of light energy and chlorophyll.
Explanation
Photosynthesis converts light energy into chemical energy stored in organic molecules. Oxygen is released as a product of the overall process.
Question Analysis
Answer
Nitrate ions provide nitrogen needed to manufacture amino acids, proteins and other nitrogen-containing compounds.
Explanation
Plants absorb mineral ions from the soil solution. Nitrogen is essential for growth because it is incorporated into important cellular molecules.
Question Analysis
Answer
- They provide a large surface area.
- Their epithelial layer is thin.
- They contain a rich network of blood capillaries.
- They contain a lacteal for transport of many absorbed lipid products.
Explanation
The villi increase the area available for absorption. Their thin surface reduces diffusion distance, while blood and lymphatic vessels carry absorbed substances away from the intestinal surface.
Question Analysis
Answer
A balanced diet provides appropriate amounts of the essential nutrients, energy and other dietary components required by the body for health and normal functioning.
Explanation
Nutritional requirements vary with factors such as age, activity and physiological condition. A balanced diet should provide a suitable variety of nutrients rather than excessive dependence on one food type.
Question Analysis
Answer
Vitamins participate in essential metabolic and physiological processes. Although required in small quantities, inadequate amounts can impair normal body functions.
Explanation
Different vitamins have different functions. They are not normally major sources of energy, but many are essential for enzymes, tissues, immunity and other processes.
Question Analysis
Answer
- Incisors are mainly adapted for cutting and biting food.
- Molars are mainly adapted for crushing and grinding food.
Explanation
Different types of teeth have different shapes that reflect their roles in mechanical digestion.
Question Analysis
Answer
Oestrogen contributes to development of the uterine lining and participates in hormonal regulation of the menstrual cycle.
Explanation
Ovarian hormones coordinate changes in the reproductive system. Oestrogen levels vary during the cycle and influence the endometrium and pituitary hormone regulation.
Question Analysis
Answer
The testes produce sperm cells and secrete male sex hormones such as testosterone.
Explanation
The testes have reproductive and endocrine functions. Sperm production supports sexual reproduction, while testosterone influences male reproductive development and function.
Question Analysis
Answer
- It allows exchange of oxygen and nutrients between maternal and fetal blood supplies.
- It allows removal of carbon dioxide and other waste products from fetal circulation.
- It produces hormones important for maintaining pregnancy.
Explanation
The placenta provides a specialised exchange surface between maternal and fetal circulations. The two blood supplies normally remain separate while substances move across the placental interface.
Question Analysis
Answer
Genotype refers to the genetic constitution of an organism, while phenotype refers to its observable characteristics resulting from genotype and environmental influences.
Explanation
Two organisms can have different genotypes but similar appearances, or similar genotypes can produce different phenotypes when environmental conditions differ.
Question Analysis
Answer
A dominant allele is an allele whose associated phenotype is expressed in a heterozygote under the conditions of simple complete dominance.
Explanation
Dominance describes the relationship between alleles and their phenotypic expression. It does not mean that the dominant allele is necessarily more common, stronger or better.
Question Analysis
Answer
A mutation is a change in genetic material, such as a change in a DNA sequence or chromosome structure.
Explanation
Mutations can arise spontaneously or as a result of mutagenic factors. Some have little effect, some are harmful and some can contribute useful variation to populations.
Question Analysis
Answer
Variation means individuals differ in characteristics. If some differences are heritable and affect survival or reproduction, natural selection can change the frequency of associated alleles in the population.
Explanation
Without heritable variation, selection would have little raw material on which to act. Over generations, advantageous inherited characteristics can become more common.
Question Analysis
Answer
A trophic level is a feeding position occupied by an organism in a food chain or food web.
Explanation
Producers occupy the first trophic level, while successive consumer levels receive energy through feeding relationships.
Question Analysis
Answer
Predation can reduce prey numbers. The strength of this effect depends on predator numbers, prey availability and environmental conditions.
Explanation
Predator and prey populations can influence each other. When prey become more abundant, predators may have more food available; increased predation can then contribute to a decline in prey numbers.
Question Analysis
Answer
Organisms compete when resources such as food, water, light, space or mates are limited.
Explanation
Competition can occur between members of the same species or between different species. Individuals that obtain sufficient resources may have greater chances of survival and reproduction.
Question Analysis
Answer
- Temperature
- Moisture availability
- Oxygen availability
- Availability and nature of organic material
Explanation
Decomposers require suitable environmental conditions. Temperature, moisture and oxygen can influence microbial activity and therefore the rate at which organic material breaks down.
Question Analysis
Answer
Quadrats provide a standard area in which organisms can be counted or estimated, allowing researchers to sample populations and compare different locations.
Explanation
Random or systematic placement of quadrats can reduce sampling bias. The results can be used to estimate abundance, density or distribution of organisms.
Question Analysis
Answer
- Protecting natural habitats.
- Establishing protected areas and reserves.
- Controlling overhunting and illegal exploitation.
- Restoring degraded ecosystems.
Explanation
Conservation aims to maintain species, genetic diversity and functioning ecosystems. Habitat protection is especially important because species depend on suitable environmental conditions.
Question Analysis
Answer
Nutrients such as nitrates and phosphates can be washed into rivers and lakes. Excess nutrients can stimulate excessive algal growth, which may contribute to oxygen depletion when organic material is decomposed.
Explanation
This process is associated with eutrophication. Changes in nutrient levels can alter aquatic ecosystems and reduce oxygen availability for aquatic organisms.
Question Analysis
Answer
They should be kept constant so that changes in the dependent variable can be more confidently attributed to the independent variable being tested.
Explanation
If several variables change at the same time, it becomes difficult to determine which factor caused the observed result. Controlling relevant variables improves the validity of the investigation.
Question Analysis
Answer
Accuracy describes how close a measurement is to the true or accepted value, while reliability describes the consistency of repeated measurements or results.
Explanation
An experiment can produce consistent results that are nevertheless far from the true value. Repetition helps assess reliability, while appropriate calibration and measurement methods help improve accuracy.
Question Analysis
Answer
A good conclusion should state what the results show in relation to the question or hypothesis and should be supported by the collected evidence.
Explanation
A conclusion should not simply repeat the procedure. It should interpret the data, identify the observed relationship and, where appropriate, mention limitations or the need for further investigation.
Question Analysis
Section B — 100 Fresh Biology MCQs
Choose the best answer for each question.
Which structure is considered the basic unit of life?
Proteins are made from smaller units called:
Which carbohydrate is commonly stored by plants?
Which is a major role of stored body fat?
Water is particularly useful as a biological solvent because it:
Most biological enzymes are:
What happens to enzyme activity when the active site is altered significantly?
Which feature helps the cell membrane regulate transport?
Active transport can move a substance:
ATP is important because it:
Which gas is consumed during aerobic respiration?
Which organelle is the major site of aerobic respiration in eukaryotic cells?
Compared with aerobic respiration, anaerobic respiration generally releases:
Which feature of alveoli reduces diffusion distance?
During inhalation, the volume of the thoracic cavity generally:
Which pigment gives red blood cells much of their characteristic colour?
Which blood component is particularly important in clot formation?
Which organ regulates the composition of urine?
Urea is produced mainly in the:
Homeostatic mechanisms commonly involve:
Evaporation of sweat helps cool the body because:
Hormones are transported around the body mainly through:
Which part of a neuron usually receives signals from other cells?
A synapse is a junction between:
Which is a major advantage of a reflex response?
Which structure changes shape to focus light onto the retina?
Which plant hormone is associated with phototropic growth?
Growth of a shoot towards light is called:
Which gas is normally needed for respiration during seed germination?
The embryo of a seed eventually develops into:
Which material is mainly transported through xylem?
Phloem transport is associated mainly with:
Stomatal opening is controlled by:
Which substance is a reactant in photosynthesis?
Which element is supplied by nitrate ions?
Which organ receives bile and pancreatic secretions?
Bile helps fat digestion by:
Which structure greatly increases the absorptive surface of the small intestine?
Which teeth are best adapted for grinding?
Which nutrient is mainly required for growth and tissue repair?
Which organ produces ova in humans?
Which hormone is mainly produced by the testes?
Where does implantation normally occur?
Which substance normally moves from maternal circulation to fetal circulation across the placenta?
The alternative forms of a gene are called:
An individual with genotype Bb is:
Which genotype is homozygous recessive?
Which process produces genetically varied gametes?
A mutation can be described as a change in:
Natural selection can change the frequency of:
A characteristic that improves survival in a particular environment is an:
A community consists of:
An ecosystem includes:
The habitat of an organism is:
Which factor decreases population size?
Competition becomes stronger when:
A predator obtains food by:
Decomposers are important because they:
Which organism is usually a primary consumer?
Why does energy decrease along many food chains?
Which process adds carbon dioxide to the atmosphere?
Which organisms are especially important in nitrogen cycling?
Eutrophication is associated with excess:
Which action directly protects natural habitats?
High biodiversity means:
A quadrat is most useful for sampling:
A transect can be used to study:
The independent variable is the variable that is:
The dependent variable is:
A control group is useful because it:
Repeating measurements can improve assessment of:
Accuracy is improved by:
A good biological drawing should be:
Which test is used to identify reducing sugars?
Which reagent is used to test for starch?
The Biuret test is used to detect:
Why might a plant be destarched before a photosynthesis experiment?
What substance is commonly tested for when demonstrating starch formation in leaves?
A hypothesis is:
A graph is useful because it can:
Which structure provides mechanical support to a plant cell?
Chloroplasts contain:
The large central vacuole in a typical plant cell contains:
The nucleus contains most of the cell’s:
Ribosomes are involved in:
Mitosis is particularly important for:
Meiosis reduces chromosome number so that:
Which microorganism is commonly used in fermentation?
Which statement about bacteria is correct?
A pathogen is:
Which cells are involved in antibody production?
Vaccination is intended to stimulate:
Which organism is a producer?
Food webs are usually more complex than food chains because they:
Ecological succession describes:
Which activity can threaten biodiversity?
Natural selection requires:
Which is an example of quantitative data?
Which is qualitative data?
Which statement best describes a scientific conclusion?
WASSCE Biology Set 3 — Paper Analysis
| Topic Area | Coverage | Question Focus | Difficulty |
|---|---|---|---|
| Cell Biology | Organisation, membranes, organelles, division | Structure and function | Easy–Moderate |
| Biochemistry | Proteins, carbohydrates, lipids and water | Biological importance | Easy |
| Enzymes | Specificity and inhibition | Application | Moderate |
| Respiration | Aerobic and anaerobic respiration | Process understanding | Moderate |
| Human Transport | Blood and clotting | Function | Easy–Moderate |
| Excretion | Kidneys, urea and water balance | Homeostasis | Moderate |
| Coordination | Nervous and hormonal systems | Responses | Moderate |
| Plant Physiology | Photosynthesis, tropisms and transport | Application | Moderate |
| Human Nutrition | Digestion, teeth and absorption | Structure and function | Easy–Moderate |
| Reproduction | Hormones, pregnancy and reproductive organs | Process | Moderate |
| Genetics | Alleles, mutations and variation | Reasoning | Moderate–Challenging |
| Ecology | Food webs, competition, populations and conservation | Application | Moderate |
| Practical Biology | Variables, sampling, food tests and data | Scientific method | Moderate–Challenging |
Difficulty Analysis
Easy Questions
Basic definitions, functions, simple identification and straightforward recall questions form the foundation of the set. These questions should be answered quickly after adequate revision.
Moderate Questions
Moderate questions require students to connect structure with function, explain biological processes or apply familiar concepts to a new situation.
Challenging Questions
The more demanding questions involve genetics, natural selection, experimental reasoning, data quality and environmental cause-and-effect relationships. These require a logically connected answer rather than isolated facts.
Biology Revision Strategy
1. Start with Cell Biology
Revise cell structures, functions, membranes, transport and cell division. These concepts form a foundation for many later Biology topics.
2. Learn Biological Molecules
Understand proteins, carbohydrates, lipids and water. Learn their functions and the food tests used to identify important nutrients.
3. Understand Processes
Do not only memorise definitions. Practise explaining respiration, photosynthesis, digestion, circulation, excretion and reproduction as sequences of events.
4. Practise Genetics
Revise alleles, genotype, phenotype, homozygous and heterozygous conditions, mutation, meiosis and natural selection.
5. Strengthen Ecology
Study populations, communities, habitats, food chains, food webs, competition, predation, nutrient cycles, succession and conservation.
6. Revise Practical Biology
Practise variables, controls, sampling methods, food tests, tables, graphs, observations, conclusions and evaluation of experimental methods.
Frequently Asked Questions
How many solved Biology questions are in Set 3?
There are 50 structured Biology questions. Every question is followed by an answer, explanation and individual analysis.
How many MCQs are included?
This set contains 100 multiple-choice Biology questions with four options and a marked correct answer.
Are these the exact official 2019 Biology questions?
No. This page contains original examination-style practice material based on common senior secondary Biology concepts. It is not a verbatim reproduction of an official examination paper.
Which Biology areas are covered?
The set covers cells, biomolecules, enzymes, respiration, circulation, excretion, homeostasis, coordination, plant physiology, nutrition, reproduction, genetics, evolution, ecology, conservation and practical Biology.
How should I use the 100 MCQs?
Try to answer the questions without checking the solutions first. After finishing, review incorrect answers and identify the topic responsible for each mistake.
Are the structured questions useful for theory preparation?
Yes. They provide practice in definitions, explanations, comparisons, process descriptions, applications and scientific reasoning.
Which questions require the most reasoning?
Genetics, natural selection, environmental pollution, experimental design, accuracy and reliability require more connected reasoning than simple definition questions.
Why should Biology students practise practical questions?
Practical questions test observation, measurement, variables, controls, data interpretation and scientific conclusions. These skills are useful across many Biology topics.
Final Biology Practice Summary
Set 3 provides a large revision collection containing 50 structured questions and 100 MCQs. The material covers both factual knowledge and application-based Biology skills.
For the best results, attempt the structured questions first, write your own answers, compare them with the solutions, and then complete the 100 MCQs as a timed revision exercise.
Students should pay particular attention to questions where they lose marks repeatedly. Revising weak topics immediately after testing them is more useful than simply attempting large numbers of questions without reviewing mistakes.
Cell Biology → Biochemistry → Enzymes → Respiration → Transport → Excretion → Homeostasis → Coordination → Plant Biology → Nutrition → Reproduction → Genetics → Ecology → Conservation → Practical Biology → MCQ Revision