Viruses and Bacteria Practice Questions
17 free Viruses and Bacteria practice questions for the Static GK. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which statement best describes viruses?
- A They are complete living cells possessing their own independent metabolism
- B They are always larger than bacteria
- C They reproduce by binary fission
- D They are infectious agents that require living host cells to replicate
Correct answer: They are infectious agents that require living host cells to replicate
Viruses cannot reproduce independently and must enter living host cells to make copies of themselves. They are not considered complete cells because they lack cellular structures and independent metabolism.
Which statement best describes bacteria?
- A They are single-celled prokaryotic organisms
- B They are non-living crystals only
- C They can only replicate inside a living host cell's machinery
- D They do not contain genetic material
Correct answer: They are single-celled prokaryotic organisms
Bacteria are single-celled prokaryotes, meaning they lack a true nucleus. Many bacteria can live and reproduce independently in suitable environments.
Which structure is present in bacteria but absent in most viruses?
- A Cell wall
- B Capsid
- C Genetic material
- D Protein coat
Correct answer: Cell wall
Many bacteria have a cell wall that provides shape and protection. Viruses generally have a protein coat called a capsid rather than a cellular wall.
Which process do bacteria commonly use for reproduction?
- A Binary fission
- B Photosynthesis
- C Budding from host cells
- D Meiosis
Correct answer: Binary fission
Bacteria commonly reproduce by binary fission, where one cell divides into two daughter cells. This allows rapid population growth under favorable conditions.
Which type of genetic material can viruses contain?
- A Only DNA
- B Only RNA
- C Either DNA or RNA
- D Neither DNA nor RNA
Correct answer: Either DNA or RNA
Viruses may contain either DNA or RNA as their genetic material. The type of genetic material is one way scientists classify viruses.
Which medicine is generally used to treat bacterial infections?
- A Antibiotics
- B Antacids
- C Vitamins
- D Analgesics only
Correct answer: Antibiotics
Antibiotics are used to kill bacteria or stop their growth. They are not effective against viruses such as those causing common colds.
Why are antibiotics usually ineffective against viral infections?
- A Viruses are always beneficial
- B Viruses are generally much larger in overall physical size than typical bacteria
- C Viruses have no structures or processes targeted by most antibiotics
- D Viruses contain no genetic material
Correct answer: Viruses have no structures or processes targeted by most antibiotics
Antibiotics target bacterial features such as cell wall synthesis or bacterial ribosomes. Viruses lack these bacterial targets, so antibiotics do not usually work against them.
Which disease is caused by a virus?
- A Tuberculosis
- B Cholera
- C Influenza
- D Typhoid
Correct answer: Influenza
Influenza is caused by influenza viruses. Tuberculosis, cholera, and typhoid are caused by bacteria.
Which bacterial disease mainly affects the lungs?
- A Dengue
- B Measles (Rubeola)
- C Tuberculosis
- D Polio
Correct answer: Tuberculosis
Tuberculosis most commonly affects the lungs, though it can affect other organs as well. It spreads mainly through airborne droplets from infected individuals.
Which viral disease is transmitted mainly by the bite of an infected mosquito?
- A Typhoid
- B Tetanus
- C Dengue fever
- D Cholera infection
Correct answer: Dengue fever
Dengue is a viral disease spread mainly by Aedes mosquitoes. Typhoid, tetanus, and cholera are bacterial diseases.
Which bacterium is commonly associated with cholera?
- A Vibrio cholerae
- B Plasmodium vivax
- C Influenza virus
- D HIV
Correct answer: Vibrio cholerae
Cholera is caused by the bacterium Vibrio cholerae. It commonly spreads through contaminated water or food.
Which virus attacks the immune system and can lead to AIDS?
- A HIV (retrovirus)
- B Rabies virus
- C Dengue virus
- D Hepatitis A virus
Correct answer: HIV (retrovirus)
HIV targets cells of the immune system, especially CD4 T cells. If untreated, HIV infection can progress to AIDS.
Which disease is prevented by the BCG vaccine?
- A Tuberculosis
- B Poliomyelitis
- C Influenza
- D Dengue fever
Correct answer: Tuberculosis
The BCG vaccine is used to help protect against tuberculosis, especially severe forms in children. It is commonly included in immunization programs in many countries.
Which vaccine is used to prevent poliomyelitis?
- A Polio vaccine
- B BCG vaccine
- C Rabies vaccine
- D Tetanus vaccine
Correct answer: Polio vaccine
Polio vaccines protect against poliovirus, which can cause paralysis. Both oral and inactivated polio vaccines are used in different immunization programs.
What are bacteriophages?
- A Viruses that infect bacteria
- B Bacteria that infect viruses
- C Fungi that kill plants
- D Parasites that infect mosquitoes
Correct answer: Viruses that infect bacteria
Bacteriophages are viruses that specifically infect bacteria. They attach to bacterial cells and use them to produce more phage particles.
Which term refers to bacteria that require oxygen for growth?
- A Aerobic bacteria
- B Anaerobic bacteria
- C Viral bacteria
- D Dormant viruses
Correct answer: Aerobic bacteria
Aerobic bacteria need oxygen to grow and survive. Anaerobic bacteria can grow without oxygen and may even be harmed by it.
Which term refers to bacteria that can grow without oxygen?
- A Anaerobic bacteria
- B Aerobic bacteria
- C Protozoal bacteria
- D Viral particles
Correct answer: Anaerobic bacteria
Anaerobic bacteria grow in environments where oxygen is absent or very limited. Some anaerobes are important in human disease and in normal body flora.