Online Test — Microorganisms and Disease
35 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 35
Microorganisms can be seen only with the help of a:
Telescope
Microscope
Magnifying mirror
Naked eye
Explanation: Microbes are too small for the naked eye and need a microscope to be seen.
Question 2 of 35
Which microorganism can reproduce only inside a living host cell?
Bacteria
Virus
Fungi
Algae
Explanation: Viruses are active and reproduce only inside a host cell.
Question 3 of 35
Which group of microbes makes its own food by photosynthesis?
Algae
Protozoa
Bacteria
Viruses
Explanation: Algae contain chlorophyll and photosynthesise like green plants.
Question 4 of 35
Amoeba and Paramecium are examples of:
Fungi
Algae
Protozoa
Viruses
Explanation: Amoeba and Paramecium are single-celled, animal-like protozoa.
Question 5 of 35
The fuzzy growth on stale bread is a:
Bacterium
Fungus
Virus
Protozoan
Explanation: The mould on bread is a fungus that grows in warm, damp conditions.
Question 6 of 35
The bacterium that fixes nitrogen in legume root nodules is:
Lactobacillus
Rhizobium
Yeast
Plasmodium
Explanation: Rhizobium lives in legume root nodules and fixes atmospheric nitrogen.
Question 7 of 35
Milk is converted into curd by:
Yeast
Algae
Lactobacillus
Virus
Explanation: Lactobacillus bacteria turn warm milk into curd.
Question 8 of 35
Yeast makes bread rise by releasing the gas:
Oxygen
Nitrogen
Carbon dioxide
Hydrogen
Explanation: Yeast ferments sugar and releases carbon dioxide, which makes dough rise.
Question 9 of 35
Penicillin, an antibiotic, is obtained from a:
Virus
Fungus
Protozoan
Alga
Explanation: Penicillin is produced by the fungus Penicillium.
Question 10 of 35
Microbes that break down dead matter and recycle nutrients are called:
Producers
Decomposers
Predators
Vectors
Explanation: Decomposer bacteria and fungi break down dead matter into soil nutrients.
Question 11 of 35
A disease-causing microorganism is called a:
Decomposer
Pathogen
Producer
Host
Explanation: Microbes that cause disease are called pathogens.
Question 12 of 35
Which disease is caused by a protozoan?
Tuberculosis
Cholera
Malaria
Typhoid
Explanation: Malaria is caused by a protozoan spread by mosquitoes.
Question 13 of 35
Rust of wheat, a plant disease, is caused by a:
Virus
Fungus
Protozoan
Alga
Explanation: Wheat rust is caused by a fungus.
Question 14 of 35
Eating spoiled food can cause food poisoning because microbes release:
Oxygen
Toxins
Vitamins
Minerals
Explanation: Spoilage microbes break down food and release harmful toxins.
Question 15 of 35
The common cold and influenza in humans are caused by:
Bacteria
Viruses
Fungi
Algae
Explanation: Colds and flu are caused by viruses.
Question 16 of 35
A disease that spreads from an infected person to a healthy one is called:
Non-communicable
Communicable
Deficiency
Hereditary
Explanation: Communicable diseases spread between people through pathogens.
Question 17 of 35
Tuberculosis mainly spreads through:
Water
Air
Soil
Touch only
Explanation: TB spreads through air in droplets from coughing or sneezing.
Question 18 of 35
Cholera and typhoid are commonly spread through:
Contaminated water
Magnets
Sunlight
Dry air
Explanation: Cholera and typhoid spread through contaminated drinking water.
Question 19 of 35
The vector that spreads malaria is the:
Housefly
Anopheles mosquito
Cockroach
Honeybee
Explanation: The female Anopheles mosquito carries the malaria parasite.
Question 20 of 35
Which is a good way to prevent water-borne diseases?
Drink unfiltered pond water
Boil drinking water
Leave food uncovered
Skip washing hands
Explanation: Boiling drinking water kills microbes and prevents water-borne diseases.
Question 21 of 35
The body's defence network against microbes is the:
Digestive system
Immune system
Nervous system
Skeletal system
Explanation: The immune system recognises and destroys harmful microbes.
Question 22 of 35
Which is part of innate (inborn), non-specific immunity?
Skin barrier
A specific antibody
Memory cell
A vaccine
Explanation: The skin is a non-specific barrier of innate immunity.
Question 23 of 35
A foreign substance that triggers an immune response is a/an:
Antibody
Antigen
Vaccine
Vector
Explanation: An antigen is the foreign substance that triggers the immune response.
Question 24 of 35
Proteins that lock onto a specific microbe to neutralise it are:
Antigens
Antibodies
Toxins
Enzymes only
Explanation: Antibodies are made to bind a specific antigen and neutralise the microbe.
Question 25 of 35
A vaccine protects us by making the body produce antibodies and:
Toxins
Memory cells
Mucus
Stomach acid
Explanation: Vaccines create memory cells (and antibodies) for fast future defence.
Question 26 of 35
Antibiotics are medicines used to fight diseases caused by:
Viruses
Bacteria
Vitamins
Allergies
Explanation: Antibiotics kill bacteria or stop their growth.
Question 27 of 35
The first antibiotic, penicillin, was discovered by:
Edward Jenner
Alexander Fleming
Louis Pasteur
Robert Koch
Explanation: Alexander Fleming discovered penicillin in 1928.
Question 28 of 35
Penicillin is produced by a:
Bacterium
Fungus (Penicillium)
Virus
Protozoan
Explanation: Penicillin comes from the fungus Penicillium.
Question 29 of 35
Taking antibiotics for a viral cold is useless because antibiotics:
Are too strong
Do not work on viruses
Cause fever
Work only outside the body
Explanation: Antibiotics act on bacteria, not viruses, so they cannot cure a viral cold.
Question 30 of 35
Overuse and misuse of antibiotics leads to:
Faster cure always
Antibiotic resistance (AMR)
More vitamins
Stronger immunity
Explanation: Misuse lets bacteria survive and become resistant, causing AMR.
Question 31 of 35
Food preservation mainly works by stopping the growth of:
Plants
Microbes
Insects only
Minerals
Explanation: Preservation stops or slows the microbes that spoil food.
Question 32 of 35
Milk is made safe and longer-lasting by heating and quick cooling, a method called:
Pickling
Pasteurisation
Canning
Irradiation
Explanation: Pasteurisation heats milk briefly and cools it fast to kill microbes.
Question 33 of 35
Refrigeration preserves food by:
Killing all microbes instantly
Slowing microbe growth with cold
Adding salt
Removing air
Explanation: Cold temperatures slow microbial growth, keeping food fresh longer.
Question 34 of 35
Drying food (dehydration) preserves it because microbes cannot grow without:
Light
Water (moisture)
Salt
Sugar
Explanation: Removing moisture prevents microbes from growing in dried food.
Question 35 of 35
Sealing heated food in airtight tins for long storage is called:
Canning
Pickling
Refrigeration
Pasteurisation
Explanation: Canning seals heated food airtight so no microbes can enter or survive.