senior exam nig - African Biology Olympiad

#1. Which of these structures is found in a plant cell but not in an animal cell?

Cell wall

Nucleus

Cell membrane

Mitochondrion

#2. Which factor is not a limiting factor of photosynthesis?

Temperature

Oxygen concentration

Carbon dioxide concentration

Light intensity

#3. What is the role of hydrochloric acid in the stomach?

To emulsify fats

To kill bacteria and provide the optimum pH for protease

To digest food

To absorb nutrients

#4. What is the correct order of a simple reflex arc?

Receptor → Motor Neurone → Relay Neurone → Sensory Neurone → Effector

Receptor → Sensory Neurone → Relay Neurone → Motor Neurone → Effector

Effector → Motor Neurone → Relay Neurone → Sensory Neurone → Receptor

Sensory Neurone → Receptor → Effector → Motor Neurone → Relay Neurone

#5. What is a stem cell?

A type of nerve cell.

A cell that is only found in embryos.

A cell that is fully specialised.

An undifferentiated cell that can divide to produce more stem cells or other cell types.

#6. What is the main problem with the overuse of antibiotics?

They lead to the development of antibiotic-resistant strains of bacteria.

They become more expensive.

They cause allergies in everyone.

They start to kill viruses.

#7. What is the name of the stage of the cell cycle where the cell grows and replicates its DNA?

Mitosis

Cytokinesis

Interphase

Prophase

#8. Which activity would primarily use anaerobic respiration?

Watching TV

Sprinting 100m

Reading a book

Sleeping

#9. Which process describes the movement of air into the lungs?

Gas Exchange

Inhalation

Respiration

Exhalation

#10. What is a vaccine?

A small dose of a dead or inactive pathogen

A type of white blood cell

A medicine that kills bacteria

A chemical that produces toxins

#11. What is the function of xylem tissue in plants?

To transport water and mineral ions

To carry out photosynthesis

To absorb light

To transport sucrose

#12. Rose Black Spot is a disease caused by a:

Virus

Protist

Bacterium

Fungus

#13. If two heterozygous, brown-eyed parents (Bb) have a child, what is the probability the child will have blue eyes?

50%

75%

25%

0%

#14. What is a placebo?

A type of antibiotic

A vaccine

A substance that is like the drug but does not contain the active ingredient

A very strong dose of a drug

#15. Why do plants need nitrate ions?

To make chlorophyll

To make proteins

For respiration

For photosynthesis

#16. What is a causal mechanism?

Something that increases the risk of developing a disease.

A correlation between two factors.

A type of treatment.

How one factor influences another to cause a disease.

#17. What is the main advantage of sexual reproduction over asexual reproduction?

It is faster.

It produces genetic variation in the offspring.

It only requires one parent.

It produces genetically identical offspring.

#18. How does the skin act as a defence against pathogens?

By engulfing bacteria

By acting as a physical barrier

By producing antibodies

By producing toxins

#19. Where is protease enzyme produced?

Pancreas

Salivary Glands

Large Intestine

Gall Bladder

#20. What is the emergence of a new species from an existing one called?

Variation

Fertilisation

Speciation

Cloning

#21. How can smoking lead to lung cancer?

Carcinogens in tobacco smoke can cause mutations in DNA.

Smoking weakens the immune system, allowing a virus to cause cancer.

Smoking causes a vitamin deficiency.

Smoking has no link to cancer.

#22. What is the definition of homeostasis?

The way organisms control their surroundings.

The control of body temperature only.

The removal of waste products from the body.

The maintenance of a stable internal environment.

#23. Which type of tissue covers the surfaces of organs?

Nervous tissue

Epithelial tissue

Muscular tissue

Glandular tissue

#24. Which blood vessel carries oxygenated blood away from the heart?

Vena Cava

Vein

Artery

Capillary

#25. What is the molecule in the nucleus of a cell that carries genetic information?

Protein

Glucose

ATP

DNA

#26. Active transport requires which of the following?

A partially permeable membrane only

Water molecules

A concentration gradient only

Energy from respiration

#27. What is the main concern about the overuse of antibiotics?

They cause viruses to become stronger.

They lead to the development of antibiotic-resistant strains of bacteria.

They are too expensive.

They become less effective.

#28. Which organ is most directly damaged by heavy alcohol consumption?

The Lungs

The Heart

The Brain

The Liver

#29. What is the main purpose of a quadrat in ecological fieldwork?

To capture small animals for study.

To estimate the population size of a species in a given area.

To measure light intensity.

To measure soil pH.

#30. What is the link between diet and cancer?

Obesity is a risk factor for some types of cancer.

Only a high-sugar diet is linked to cancer.

A poor diet can directly cause cancer in all cases.

There is no link between diet and cancer.

#31. What is the term for all the organisms of one species in a habitat?

Community

Environment

Population

Ecosystem

#32. How do most contraceptive pills prevent pregnancy?

They create a barrier to the egg.

They kill sperm.

They contain oestrogen which inhibits FSH production, so no eggs mature.

They make the uterus lining inhospitable.

#33. Which type of drug was first discovered from the Penicillium mould?

Aspirin

Paracetamol

Digitalis

Penicillin

#34. Which component of blood is responsible for clotting?

White Blood Cells

Platelets

Plasma

Red Blood Cells

#35. A person gets chickenpox and then recovers. They are unlikely to get it again. What type of immunity is this?

Artificial active immunity

Herd immunity

Passive immunity

Natural active immunity

#36. The loss of water vapour from plant leaves is called:

Transpiration

Respiration

Translocation

Transportation

#37. Which chamber of the heart pumps blood to the lungs?

Right Ventricle

Left Ventricle

Left Atrium

Right Atrium

#38. What is the function of the hormone insulin?

To prepare the body for fight or flight.

To decrease blood glucose levels by converting glucose to glycogen in the liver.

To increase blood glucose levels.

To control the menstrual cycle.

#39. HIV initially leads to a person being more susceptible to other infections because it attacks:

The liver

The nervous system

The immune system (white blood cells)

Red blood cells

#40. Calculate the magnification if the image size is 5mm and the real size is 0.002mm.

x5000

x250

x2500

x500

#41. How can the spread of Salmonella food poisoning be reduced?

Washing hands after gardening

Using fungicides

Using mosquito nets

Vaccinating chickens

#42. Which disease is spread by direct sexual contact?

Gonorrhoea

Malaria

Measles

Tuberculosis (TB)

#43. Which scientist proposed the theory of evolution by natural selection?

Carl Linnaeus

Gregor Mendel

Charles Darwin

Jean-Baptiste Lamarck

#44. What is the function of phloem tissue in plants?

To transport sucrose (dissolved sugars)

To absorb minerals

To support the plant

To transport water

#45. In a double-blind trial, who does not know which patients received the placebo and which received the real drug?

The government

Only the doctors

Only the patients

Both the patients and the doctors

#46. A plant is kept in the dark for 48 hours. What will happen to the rate of photosynthesis?

It will increase.

It will stop completely.

It will stay the same.

It will decrease.

#47. Where are chromosomes found in a cell?

Cytoplasm

Mitochondria

Nucleus

Cell membrane

#48. Which hormone is released by the adrenal glands in response to stress?

Insulin

Testosterone

Progesterone

Adrenaline

#49. Which of the following is a use of monoclonal antibodies?

To carry oxygen around the body

To digest food

In pregnancy tests to detect hCG hormone

To treat vitamin deficiencies

#50. Which of the following is an example of selective breeding?

A farmer crosses his best milk-producing cows to produce calves that yield more milk.

A plant is genetically modified to be resistant to herbicides.

A bacterium develops resistance to an antibiotic.

A bird's beak shape changes over generations due to a change in available food.

#51. Which substance moves into cells by osmosis?

Glucose

Starch

Water

Oxygen

#52. Which disease is caused by a virus and is spread by droplet infection?

Gonorrhoea

Measles

Cholera

Rose Black Spot

#53. Which of the following is a biotic factor in an ecosystem?

Competition for food

Light intensity

Soil pH

Temperature

#54. In which type of reproduction is mitosis the main form of cell division?

Both sexual and asexual

Neither

Asexual reproduction

Sexual reproduction

#55. Which type of respiration does not require oxygen?

Aerobic respiration

Anaerobic respiration

Gas exchange

Photosynthesis

#56. What is the main role of decomposers like bacteria and fungi in an ecosystem?

To produce oxygen.

To break down dead organisms and waste materials, recycling nutrients.

To capture energy from the sun.

To act as primary consumers.

#57. A surge in which hormone triggers ovulation (the release of an egg)?

Luteinising Hormone (LH)

Progesterone

Oestrogen

Follicle-Stimulating Hormone (FSH)

#58. In a genetic cross, the allele for brown eyes (B) is dominant to the allele for blue eyes (b). What is the genotype of a homozygous, brown-eyed individual?

BB

B

Bb

bb

#59. What is the function of the permanent vacuole in a plant cell?

To control the cell

To carry out photosynthesis

To store cell sap and provide support

To make proteins

#60. What is the primary purpose of respiration?

To produce glucose

To absorb light

To produce oxygen

To release energy from glucose

#61. How does temperature affect the rate of photosynthesis?

The rate increases up to an optimum, then decreases as enzymes denature.

As temperature increases, the rate always increases.

Temperature has no effect.

As temperature increases, the rate always decreases.

#62. How many chromosomes are found in a human gamete (sperm or egg cell)?

92

46

23

2

#63. What is ‘herd immunity’?

When animals are immune to human diseases.

When antibiotics are used on farm animals.

When everyone in a population catches a disease.

When a large proportion of the population is vaccinated, reducing the spread of the disease.

#64. Why are antibiotics ineffective against viral diseases like the common cold?

Viruses are not living organisms.

Viruses are too small.

Viruses are resistant to all drugs.

Antibiotics cannot destroy viruses because they live inside body cells.

#65. In which organelle does photosynthesis take place?

Ribosome

Chloroplast

Mitochondrion

Nucleus

#66. Why is meiosis important for sexual reproduction?

It produces cells that are genetically identical.

It increases genetic variation.

It only happens in plants.

It ensures the offspring has the same number of chromosomes as the parents.

#67. Tobacco Mosaic Virus (TMV) affects plants. What is a symptom?

Black spots on leaves

A mosaic pattern of discolouration on the leaves

Stunted growth

Root rot

#68. Where in the cell does most aerobic respiration take place?

Mitochondrion

Nucleus

Chloroplast

Ribosome

#69. Which enzyme breaks down starch into sugars?

Amylase

Bile

Protease

Lipase

#70. Which part of the eye contains light-sensitive cells (rods and cones)?

Cornea

Retina

Iris

Lens

#71. Which process in the water cycle involves the change of water from a liquid to a vapour?

Condensation

Evaporation

Transpiration

Precipitation

#72. A person who does not smoke, has a balanced diet, and exercises regularly is:

Less likely to develop certain non-communicable diseases.

Guaranteed to never get a non-communicable disease.

Completely immune to all diseases.

More likely to get infectious diseases.

#73. Which process returns carbon dioxide to the atmosphere?

Consumption

Nitrogen fixation

Photosynthesis

Respiration

#74. What is the product of protein digestion?

Sugars

Fatty Acids

Amino Acids

Glycerol

#75. A build-up of fatty material in the arteries is called:

Thrombosis

Cancer

Atherosclerosis

Diabetes

#76. In yeast, anaerobic respiration produces:

Lactic Acid

Glucose only

Oxygen and Water

Ethanol and Carbon Dioxide

#77. What causes an ‘oxygen debt’ after vigorous exercise?

The lack of oxygen during anaerobic respiration, requiring oxygen to break down the lactic acid.

The need to breathe in more carbon dioxide.

The body needs oxygen for photosynthesis.

The production of too much glucose.

#78. Which of the following is a benefit of maintaining biodiversity?

It makes it easier for diseases to spread.

It reduces the number of species.

It protects potential future resources like medicines.

It makes ecosystems less stable.

#79. Which of the following is a major threat to biodiversity?

Habitat destruction

Increased recycling

Sustainable resource use

Conservation programs

#80. What happens during the ‘metaphase’ stage of mitosis?

Chromosomes are pulled apart to opposite poles.

The nuclear envelope breaks down.

Two new nuclei form.

Chromosomes line up at the equator of the cell.

#81. What is the definition of evolution?

The change in the inherited characteristics of a population over time.

The development of new species in one generation.

The extinction of a species.

The way an individual changes during its lifetime.

#82. Which cell is adapted for transmitting electrical impulses?

Palisade cell

Red blood cell

Root hair cell

Nerve cell

#83. Which mineral ion is needed to make chlorophyll?

Magnesium

Nitrate

Phosphate

Potassium

#84. What is the correct order of organisation in a multicellular organism?

Organ System → Organ → Tissue → Cell

Cell → Tissue → Organ → Organ System

Organ → Cell → Tissue → Organ System

Tissue → Cell → Organ System → Organ

#85. Which process produces gametes?

Mitosis

Fertilisation

Cloning

Meiosis

#86. What is the name of the gap between two neurons where impulses are transmitted chemically?

Nucleus

Axon

Synapse

Dendrite

#87. Which gland is known as the ‘master gland’ because it secretes several hormones that control other glands?

Adrenal gland

Pancreas

Thyroid gland

Pituitary gland

#88. A section of DNA that codes for a specific protein is called a:

Chromosome

Gene

Allele

Nucleus

#89. Which disease is characterised by the inability to control blood sugar levels?

Scurvy

Type 2 Diabetes

Coronary Heart Disease (CHD)

Cancer

#90. Which of the following is a result of meiosis?

Production of genetically identical cells

Asexual reproduction in bacteria

Growth and repair of tissues

Production of gametes (sex cells)

#91. How many chromosomes are in a normal human body cell?

92

2

23

46

#92. What is the source of energy for almost all life on Earth?

Water

The Sun

Wind

Soil

#93. Which part of the brain is responsible for coordinating muscle activity and balance

Cerebellum

Pituitary gland

Medulla

Cerebrum

#94. Where is the energy released in respiration transferred to?

A molecule called Chlorophyll

A molecule called DNA

A molecule called ATP

A molecule called Glucose

#95. A red blood cell is placed in pure water. What will happen to it?

Swell and burst

Shrink and become crinkled

Stay the same size

Release oxygen

#96. What is the green pigment in chloroplasts that absorbs light?

Chlorophyll

Melanin

Carotene

Hemoglobin

#97. Which type of tumour is benign?

A tumour that is always harmless.

A tumour that grows slowly and remains in one place.

A tumour that invades neighbouring tissues and can spread.

A tumour caused by a virus.

#98. Which organ produces bile?

Liver

Gall Bladder

Pancreas

Stomach

#99. Which organ system is the stomach part of?

Circulatory System

Nervous System

Digestive System

Respiratory System

#100. Which of the following is a plant organ?

Phloem

Xylem

Mesophyll

Leaf

#101. In a food chain, what is the name given to the organism that gets its energy directly from the sun?

Secondary Consumer

Primary Consumer

Decomposer

Producer

#102. What is the correct order of the stages of mitosis?

Prophase, Metaphase, Anaphase, Telophase

Anaphase, Telophase, Metaphase, Prophase

Prophase, Metaphase, Telophase, Anaphase

Metaphase, Prophase, Telophase, Anaphase

#103. Producing monoclonal antibodies involves the fusion of a specific white blood cell with what type of cell?

A red blood cell

A liver cell

A tumour cell

A skin cell

#104. What is the function of red blood cells?

To fight infection

To form clots

To carry oxygen

To carry blood plasma

#105. Which of the following is a potential use of adult stem cells?

To create a whole new organism

To create plant clones

They have no medical uses

To treat conditions like sickle cell anaemia

#106. How are the alveoli adapted for gas exchange?

Moist lining

Thick walls

Small surface area

Poor blood supply

#107. What is biodiversity?

The number of animals in an area.

The study of life.

The variety of all the different species of organisms on Earth or within an ecosystem.

The number of plants in an area.

#108. What is the word equation for photosynthesis?

Oxygen + Water → Glucose + Carbon Dioxide

Glucose + Oxygen → Carbon Dioxide + Water

Carbon Dioxide + Glucose → Oxygen + Water

Carbon Dioxide + Water → Glucose + Oxygen

#109. Assume a graph showing blood glucose levels after a meal. Which process is happening at point X where the level is decreasing? (Assume a graph showing a peak then a decline)

Glucose is being released from the liver.

Glucagon is being released.

Insulin is being released.

Glycogen is being converted to glucose.

#110. What is the role of the coronary arteries?

To carry deoxygenated blood to the heart

To supply blood to the heart muscle itself

To supply blood to the lungs

To pump blood

#111. In an investigation, a pondweed is placed closer to a light source. What is the independent variable?

The temperature of the water

The light intensity

The type of pondweed

The amount of oxygen produced

#112. Lipase enzymes break down lipids (fats) into:

Sugars and Fatty Acids

Amino Acids and Glycerol

Fatty Acids and Glycerol

Glycerol and Sugars

#113. What is the name for the method of using living organisms to control a pest population?

Biological Control

Selective Breeding

Genetic Engineering

Pesticide Control

#114. What is the purpose of pre-clinical testing of a new drug?

To mass-produce the drug

To see if doctors like the drug

To test on human patients

To test for toxicity and efficacy in a lab using cells, tissues and live animals

#115. What type of pathogen causes Lassa Fever?

Fungus

Protist

Bacterium

Virus

#116. What does the term ‘survival of the fittest’ mean?

Only the fastest individuals survive.

Individuals with characteristics best suited to their environment are more likely to survive and reproduce.

The biggest individuals get the most resources.

The strongest individuals always survive.

#117. What is the main function of the ribosomes?

Protein synthesis

Control of the cell's activities

Storage of cell sap

Energy release

#118. The process of anaerobic respiration in yeast is called:

Photosynthesis

Digestion

Transpiration

Fermentation

#119. What is the function of bile?

To digest starch

To absorb water

To digest proteins

To emulsify fats and neutralise stomach acid

#120. Type 1 diabetes is a condition where the pancreas produces little or no insulin. How is it typically treated?

By transplanting a new pancreas.

By taking tablets to reduce sugar absorption.

By insulin injections.

By a controlled diet and exercise.

#121. A sperm cell is a gamete. How many chromosomes does it contain?

23

92

0

46

#122. What happens to most of the energy as it is transferred from one trophic level to the next in a food chain?

It is stored in the consumer's body.

It is lost as heat during respiration, movement, and other life processes.

It is passed on to the next consumer.

It is recycled by decomposers.

#123. Which of the following has the highest magnification?

A camera lens

An electron microscope

A light microscope

A magnifying glass

#124. In the menstrual cycle, which hormone causes the lining of the uterus to build up?

Progesterone

Oestrogen

Follicle-Stimulating Hormone (FSH)

Luteinising Hormone (LH)

#125. What is the role of negative feedback in homeostasis?

To detect a change and bring the system back to its normal level.

To ignore small changes in the internal environment.

To initiate a new process unrelated to the change.

To amplify a change away from the normal level.

#126. How is Cholera spread?

By direct contact

By contaminated water

By the bite of a mosquito (vector)

By droplet infection

#127. A sperm cell is adapted for swimming to an egg cell. Which cell structure provides the energy for this movement?

Ribosome

Nucleus

Cell membrane

Mitochondria

#128. Which type of blood vessel has valves to prevent the backflow of blood?

Aorta

Capillary

Artery

Vein

#129. What is an advantage of aerobic respiration over anaerobic respiration?

It produces lactic acid.

It does not require oxygen.

It releases more energy per glucose molecule.

It is faster.

#130. What is a use of the glucose produced in photosynthesis?

Used to make cell walls (cellulose)

Released as oxygen

Stored in the liver

Used in respiration

#131. Which process is used to produce a genetically identical copy of an organism?

Cloning

Natural Selection

Speciation

Sexual Reproduction

#132. A plant with yellow leaves may be deficient in:

Phosphate ions

Water

Nitrate ions

Magnesium ions

#133. Which type of neuron carries impulses from a receptor to the central nervous system (CNS)?

Relay neurone

Motor neurone

Synaptic neurone

Sensory neurone

#134. What is the role of white blood cells in defence against disease?

Clotting blood

Phagocytosis

Carrying oxygen

Endometriosis

#135. What is the word equation for aerobic respiration?

Glucose → Lactic Acid

Carbon Dioxide + Water → Glucose + Oxygen

Glucose + Oxygen → Carbon Dioxide + Water

Glucose → Ethanol + Carbon Dioxide

#136. The main function of the large intestine is to:

Absorb water

Digest proteins

Produce enzymes

Emulsify fats

#137. Which non-communicable disease is caused by a vitamin C deficiency?

Rickets

Scurvy

Anemia

Beri-Beri

#138. Which of the following is a risk factor for non-communicable diseases?

Washing your hands

Being infected by a pathogen

Having a vaccination

Smoking

#139. Liver cirrhosis is a non-communicable disease strongly linked to:

Lack of exercise

A high-fat diet

Excessive alcohol consumption

Smoking

#140. What is glucose converted into for storage in plants?

Starch

Protein

Cellulose

Lipids

#141. How do antibiotics work?

They prevent disease by stimulating antibody production.

They kill bacteria.

They kill viruses.

They kill all types of pathogen.

#142. What is the name of the process where a white blood cell surrounds and engulfs a pathogen?

Vaccination

Antitoxin production

Phagocytosis

Antibody production

#143. Where in the digestive system is digested food absorbed into the blood?

Oesophagus

Stomach

Large Intestine

Small Intestine

#144. Which process is used by root hair cells to absorb mineral ions from the soil if the concentration in the cell is already higher than in the soil?

Diffusion

Evaporation

Osmosis

Active transport

#145. What is the term for all the populations of different species living and interacting in a particular place?

Population

Community

Ecosystem

Environment

#146. The formation of a new species often requires which of the following?

A sudden change in the environment that kills all life.

All individuals in a population to have identical DNA.

Two populations to remain in the same environment.

Geographical isolation of two populations.

#147. The process of cell division that produces two identical daughter cells is called:

Fertilisation

Meiosis

Mitosis

Differentiation

#148. How does the body respond to exercise?

Blood flow to the gut increases

The arteries to the muscles dilate

Heart rate decreases

Breathing rate decreases

#149. In human muscles, what is the product of anaerobic respiration?

Ethanol and Carbon Dioxide

Lactic Acid

Carbon Dioxide and Water

Oxygen and Glucose

#150. Diffusion is:

The movement of water from a dilute to a concentrated solution.

The movement of particles from an area of high concentration to an area of low concentration.

The movement of particles against a concentration gradient using energy.

The movement of particles from an area of low concentration to an area of high concentration.