Pathogens Practice Questions
20 free Pathogens practice questions for the General Science. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
What is a pathogen?
- A A harmless microorganism
- B A disease-causing agent
- C A type of nutrient
- D A medical instrument
Correct answer: A disease-causing agent
A pathogen is any organism or agent that causes disease in its host. Pathogens include bacteria, viruses, fungi, and parasites. They invade the body and disrupt normal biological functions.
Which of the following is an example of a bacterial pathogen?
- A Influenza virus
- B Plasmodium
- C Salmonella
- D Candida
Correct answer: Salmonella
Salmonella is a genus of bacteria that can cause foodborne illness. It infects the gastrointestinal tract and leads to symptoms like diarrhea and fever. It is transmitted through contaminated food and water.
Viruses differ from bacteria because viruses:
- A Are much larger than bacteria
- B Can always reproduce independently
- C Require a host cell to replicate
- D Have a complete cellular structure
Correct answer: Require a host cell to replicate
Viruses cannot reproduce on their own and must infect a host cell to replicate. They lack cellular structure and depend on the host’s machinery. Bacteria, in contrast, are living cells that can reproduce independently.
Which pathogen is responsible for malaria?
- A Plasmodium
- B E. coli
- C Streptococcus
- D Hepatitis B virus
Correct answer: Plasmodium
Malaria is caused by the protozoan parasite Plasmodium. It is transmitted to humans through the bite of infected Anopheles mosquitoes. The parasite infects red blood cells and causes fever and chills.
Fungal pathogens commonly cause infections in which part of the body?
- A The bones only
- B Skin and nails
- C The heart only
- D The brain only
Correct answer: Skin and nails
Fungal pathogens often infect the skin, hair, and nails. Examples include athlete’s foot and ringworm. Some fungi can also cause systemic infections in immunocompromised individuals.
Which structure allows some bacteria to move?
- A Outer membrane
- B Flagellum
- C Cell wall
- D Ribosome
Correct answer: Flagellum
The flagellum is a whip-like structure that enables bacterial movement. It helps bacteria travel toward favorable environments. Not all bacteria possess flagella.
Which pathogen causes tuberculosis?
- A Mycobacterium tuberculosis
- B Escherichia coli
- C Human Immunodeficiency Virus
- D Plasmodium falciparum
Correct answer: Mycobacterium tuberculosis
Tuberculosis is caused by Mycobacterium tuberculosis. It primarily affects the lungs and spreads through airborne droplets. It remains a major global health concern.
What is the main mode of transmission for influenza virus?
- A Contaminated soil
- B Mosquito bites
- C Respiratory droplets
- D Direct blood transfusion only
Correct answer: Respiratory droplets
Influenza virus spreads mainly through respiratory droplets when an infected person coughs or sneezes. It can also spread via contaminated surfaces. Proper hygiene reduces transmission.
Which of the following is a parasitic worm?
- A Taenia solium
- B Salmonella
- C Influenza virus
- D Candida
Correct answer: Taenia solium
Taenia is a genus of parasitic tapeworms. These worms infect the human intestine after ingestion of contaminated food. They are classified as helminths.
Antibiotics are effective primarily against:
- A Viral pathogens
- B Bacteria
- C Fungi
- D Protozoa
Correct answer: Bacteria
Antibiotics target bacterial structures or processes, such as cell wall synthesis. They are not effective against viruses. Misuse of antibiotics can lead to resistance.
Which viral pathogen attacks the immune system?
- A The HIV retrovirus
- B The Ebola filovirus
- C The rabies lyssavirus
- D The poliovirus
Correct answer: The HIV retrovirus
HIV infects and destroys CD4+ T cells of the immune system. This weakens the body’s defense against infections. Untreated HIV infection can progress to AIDS.
What is the function of a bacterial capsule?
- A Protein synthesis
- B Energy production
- C Host immune evasion
- D DNA replication and repair
Correct answer: Host immune evasion
A bacterial capsule is a protective outer layer. It helps bacteria evade the host’s immune system. This increases the pathogen’s virulence.
Which pathogen causes cholera?
- A Vibrio cholerae
- B Staphylococcus aureus
- C Hepatitis C
- D Candida albicans
Correct answer: Vibrio cholerae
Cholera is caused by the bacterium Vibrio cholerae. It spreads through contaminated water and food. The infection leads to severe dehydration due to diarrhea.
What is the term for the ability of a pathogen to cause disease?
- A Immunity
- B Virulence
- C Resistance
- D Mutation
Correct answer: Virulence
Virulence refers to the degree of pathogenicity of an organism. Highly virulent pathogens cause severe disease. It depends on various factors like toxins and immune evasion.
Which disease is caused by a prion?
- A Mad cow disease
- B Malaria fever
- C Tuberculosis
- D Seasonal influenza
Correct answer: Mad cow disease
Mad cow disease is caused by prions, which are misfolded proteins. Prions cause neurodegenerative diseases by inducing abnormal protein folding. They are distinct from bacteria and viruses.
Which of the following is an example of a viral disease?
- A Measles
- B Tetanus
- C Typhoid
- D Cholera
Correct answer: Measles
Measles is caused by the measles virus. It spreads through respiratory droplets and causes fever and rash. Tetanus, typhoid, and cholera are caused by bacteria.
Which immune response component directly destroys infected cells?
- A Circulating red blood cells
- B Blood platelets
- C Cytotoxic T cells
- D Insulin hormone
Correct answer: Cytotoxic T cells
Cytotoxic T cells recognize and kill infected cells. They play a crucial role in controlling viral infections. This helps limit pathogen spread within the body.
Which factor increases the spread of waterborne pathogens?
- A Boiling water
- B Proper sanitation
- C Contaminated water supply
- D Vaccination
Correct answer: Contaminated water supply
Contaminated water supplies facilitate the transmission of waterborne pathogens. Diseases like cholera and typhoid spread through unsafe water. Improved sanitation reduces such risks.
Which laboratory technique is commonly used to identify pathogens by amplifying their genetic material?
- A X-ray imaging
- B Polymerase chain reaction
- C Electrolysis
- D Distillation
Correct answer: Polymerase chain reaction
Polymerase chain reaction (PCR) amplifies specific DNA sequences of pathogens. It allows rapid and accurate detection. PCR is widely used in diagnosing infectious diseases.
Which term describes the time between pathogen entry and appearance of symptoms?
- A Latency period
- B Incubation period
- C Recovery period
- D Transmission phase
Correct answer: Incubation period
The incubation period is the time between infection and symptom onset. It varies depending on the pathogen. Understanding it helps in disease control and quarantine measures.