What are microorganisms?
A.Large animals that live in water
B.Plants that grow in soil
C.Tiny living organisms that cannot be seen with naked eye
D.Insects that live underground
Which of the following is NOT a major group of microorganisms?
A.Bacteria
B.Fungi
C.Mammals
D.Protozoa
What makes viruses different from other microorganisms?
A.They are larger in size
B.They can only reproduce inside host cells
C.They live only in water
D.They are visible to naked eye
Which bacterium is responsible for converting milk into curd?
A.Rhizobium
B.Lactobacillus
C.Streptomycin
D.E. coli
Why does bread dough rise when yeast is added?
A.Yeast makes the dough warm
B.Yeast produces carbon dioxide gas during respiration
C.Yeast adds water to the dough
D.Yeast makes the dough sweet
What is fermentation?
A.Conversion of sugar into alcohol
B.Conversion of milk into water
C.Conversion of bread into cake
D.Conversion of oil into vinegar
Who discovered penicillin and in which year?
A.Louis Pasteur in 1857
B.Alexander Fleming in 1929
C.Edward Jenner in 1798
D.Robert Koch in 1876
What are antibiotics?
A.Medicines that cure all diseases
B.Medicines that kill or stop growth of disease-causing microorganisms
C.Vitamins that make us stronger
D.Medicines that prevent aging
Why should antibiotics be taken only on doctor's advice?
A.They are expensive
B.Wrong use can make them less effective and kill beneficial bacteria
C.They taste bad
D.They cause immediate side effects
How does a vaccine work?
A.It kills all germs in the body
B.It introduces dead or weakened microbes to help body build immunity
C.It makes the body stronger
D.It provides instant cure for diseases
Which microorganism lives in root nodules of leguminous plants?
A.Lactobacillus
B.Rhizobium
C.Yeast
D.Penicillium
What percentage of Earth's atmosphere is nitrogen?
Why is nitrogen fixation important?
A.Plants cannot use atmospheric nitrogen directly
B.It makes the air cleaner
C.It produces oxygen
D.It prevents pollution
What are communicable diseases?
A.Diseases that cannot be cured
B.Diseases that spread from infected to healthy person
C.Diseases that affect only animals
D.Diseases that occur due to accidents
Which mosquito carries the malaria parasite?
A.Male Anopheles mosquito
B.Female Anopheles mosquito
C.Female Aedes mosquito
D.Male Aedes mosquito
How can we prevent mosquito-borne diseases?
A.By using more antibiotics
B.By preventing water collection where mosquitoes breed
C.By staying indoors always
D.By eating more vitamins
What causes food poisoning?
A.Eating too much food
B.Microorganisms that produce toxic substances in food
C.Eating spicy food
D.Eating cold food
Why does common salt help preserve food?
A.It makes food taste better
B.It draws out moisture and prevents bacterial growth
C.It adds nutrients to food
D.It makes food look more attractive
What is pasteurization?
A.Adding preservatives to milk
B.Heating milk to 70°C for 15-30 seconds then cooling rapidly
C.Boiling milk for one hour
D.Freezing milk to kill germs
Who discovered pasteurization?
A.Alexander Fleming
B.Edward Jenner
C.Louis Pasteur
D.Robert Koch
Why do we keep food in the refrigerator?
A.To make it taste better
B.Low temperature inhibits growth of microbes
C.To make it look fresh
D.To save space
What are preservatives?
A.Chemicals that improve food taste
B.Chemicals that prevent growth of microorganisms in food
C.Chemicals that add color to food
D.Chemicals that increase food nutrients
How do microorganisms help clean the environment?
A.They eat plastic waste
B.They decompose dead organic matter into simple substances
C.They produce oxygen
D.They absorb pollution from air
Which of the following materials will NOT decompose in soil?
A.Vegetable peels
B.Leaves
C.Plastic bags
D.Fruit waste
What disease does the bacterium Bacillus anthracis cause?
A.Tuberculosis
B.Anthrax
C.Cholera
D.Malaria
What type of organism causes malaria?
A.Bacteria
B.Virus
C.Protozoa
D.Fungi
Why are antibiotics not effective against cold and flu?
A.Cold and flu are too serious
B.Cold and flu are caused by viruses, not bacteria
C.Antibiotics are too weak
D.Cold and flu affect only children
What happens during the nitrogen cycle?
A.Nitrogen is completely removed from atmosphere
B.Nitrogen moves between atmosphere, soil, and living organisms
C.Nitrogen is converted to oxygen
D.Nitrogen disappears from Earth
Why do jams and jellies not spoil quickly?
A.They contain no water
B.High sugar content prevents bacterial growth
C.They are always kept frozen
D.They contain natural antibiotics
What is the main difference between beneficial and harmful microorganisms?
A.Size difference
B.Color difference
C.Beneficial ones help us while harmful ones cause diseases
D.Location where they live
Why should we cover our food?
A.To keep it warm
B.To prevent flies from contaminating food with pathogens
C.To make it look better
D.To prevent it from drying
What is the symbiotic relationship between Rhizobium and leguminous plants?
A.Rhizobium harms the plant
B.Both benefit: plant gets nitrogen, bacteria gets shelter and food
C.Only the plant benefits
D.Only the bacteria benefits
How do vaccines provide long-term protection?
A.They kill all germs permanently
B.Body remembers how to fight the microbe and produces antibodies when needed
C.They make the body immune to all diseases
D.They strengthen the body permanently
What would happen if all decomposer microorganisms disappeared?
A.Nothing would change
B.Dead organic matter would accumulate and nutrients wouldn't be recycled
C.All plants would grow better
D.The air would become cleaner
Why is it important to complete the full course of antibiotics?
A.To avoid waste
B.To ensure all harmful bacteria are killed and prevent antibiotic resistance
C.To make the medicine more effective
D.To avoid side effects
How do blue-green algae help in agriculture?
A.They produce oxygen
B.They fix atmospheric nitrogen and increase soil fertility
C.They produce food
D.They prevent plant diseases
What makes packaged milk safe to drink without boiling?
A.It contains preservatives
B.It has been pasteurized to kill harmful microbes
C.It is kept in sealed containers
D.It has been filtered
Why can microorganisms survive in extreme conditions?
A.They are very large
B.They have simple structure and can adapt quickly
C.They don't need food
D.They don't need oxygen
How does oil and vinegar preserve pickles?
A.They add flavor
B.They create acidic conditions where bacteria cannot survive
C.They add nutrients
D.They make pickles colorful
What is the role of microorganisms in sewage treatment?
A.They make sewage smell better
B.They break down organic pollutants and clean water
C.They add chemicals to water
D.They remove all water
Why do we add a small amount of curd to warm milk to make more curd?
A.To make it taste better
B.Curd contains Lactobacillus bacteria that multiply and convert milk
C.To make it thicker
D.To change its color
What happens to the nitrogen percentage in atmosphere over time?
A.It keeps increasing
B.It keeps decreasing
C.It remains more or less constant due to nitrogen cycle
D.It varies randomly
How do microorganisms in soil help farmers?
A.They eat harmful insects
B.They decompose organic waste into nutrient-rich manure
C.They prevent soil erosion
D.They produce seeds
What precautions should be taken to prevent water-borne diseases?
A.Drink only cold water
B.Drink boiled or properly treated water
C.Drink water only in the morning
D.Add sugar to water
Why is vaccination important for children?
A.It makes them grow faster
B.It protects them from serious diseases by building immunity
C.It makes them stronger
D.It improves their appetite
How do microorganisms contribute to the carbon cycle?
A.They produce carbon dioxide during decomposition
B.They absorb carbon from air
C.They convert carbon to nitrogen
D.They store carbon permanently
What is the difference between sterilization and pasteurization?
A.No difference, they are the same
B.Sterilization kills all microorganisms, pasteurization kills only harmful ones
C.Sterilization is for liquids, pasteurization for solids
D.Sterilization is faster than pasteurization
How do modern food preservation techniques help society?
A.They make food more expensive
B.They allow food to be stored longer and transported safely
C.They change food taste
D.They make food preparation faster
What lesson does studying microorganisms teach us about invisible threats and benefits in our environment?
A.Only visible things matter
B.Small, invisible organisms can have huge impacts on our lives and environment
C.Microorganisms are not important
D.Only harmful microorganisms exist