General Microbiology MCQs with Answer Keys (1-10)

1. If a scientist actively researches the frequency and distribution of the diseases, he is said to be a:
   a. Mycologist
   b. Immunologist           
   c. Etiologist
   d. Epidemiologist
   e. Ecologist
2. The biggest obstacle in the acceptance and development of the science of microbiology was:
   a. Lack of effective vaccines
   b. Lack of sterile containers
   c. Theory of spontaneous generation
   d. Absence of debilitating diseases before the seventeenth-century   
   e. Use of aseptic technique
3. The germ theory of disease states that:
   a. Microorganisms that invade other organisms can cause disease in those organisms
   b. Microorganisms can spontaneously arise in debilitated hosts
   c. Microorganisms don’t cause infectious diseases
   d. Not all microorganisms are harmful
   e. All microorganisms are beneficial to humans in one way or another
4. When determining distances and sizes, the smallest unit of measurement is the:
   a. Millimeter
   b. Micrometer      
   c. Centimeter
   d. Decimeter
   e. Nanometer
5. The average wavelength of light visible to our eye is:
   a. 800 nm        
   b. 200 nm        
   c. 550 nm
   d. 100 nm      
   e. 420 nm
6. In a light microscope, what function does the condenser serve?
   a. Focuses the light rays onto our eyes
   b. Magnifies the light rays after their passage through the sample
   c. Focuses the light rays on sample
   d. Increases the light intensity
   e. Reduces glare
7. The total magnification of a microscope is calculated by:
   a. Addition of the objective lens and ocular lens magnification powers
   b. Multiplication of the objective lens and ocular lens magnification powers
   c. Multiplication of the objective lens and condenser lens magnification powers
   d. The objective lens power squared
   e. None of the above
8. Which stains are frequently used to identify mycobacterium and other bacteria whose cell walls contain high amounts of lipids?
   a. Gram stain
   b. Schaeffer-Fulton stain          
   c. Acid-fast stain
   d.Giemsa Stain
   e. Spore stain
9. Which of the following microscopic techniques provide three-dimensional images of a bacterial cell?
   a. Transmission Electron Microscopy
   b. Scanning Electron Microscopy
   c. Negative staining microscopy
   d. Dark-field microscopy
   e. Fluorescent microscopy
10. The transmission electron microscope has the greatest resolving power because it uses an electron beam to view the sample instead of a light beam. The electron beam is used because
    a. Electrons have longer wavelengths than light waves
    b. Electrons do not penetrate the sample
    c. Light waves are less visible
    d. Electrons have shorter wavelengths than light waves
    e. Electrons are less invasive.

Answer Keys

1. d. Epidemiologist
2. c. Theory of spontaneous generation
3. a. Microorganisms that invade other organisms can cause disease in those organisms
4. e. Nanometer
5. c. 550 nm
6. c. Focuses the light rays on sample
7. b. Multiplication of the objective lens and ocular lens magnification powers
8. c. Acid-fast stain
9. b. Scanning Electron Microscopy
10. d. Electrons have shorter wavelengths than light waves