WESTCOTT MICROBIO FINAL QUESTIONS AND ANSWERS 2025
Section 1: Fundamentals & History (25 Questions)
1. Who is credited with first observing microorganisms using a simple microscope?
- ANSWER: Antonie van Leeuwenhoek
2. What is the primary purpose of Koch's Postulates?
- ANSWER: To establish a causal relationship between a specific microorganism and a specific
disease.
3. The theory that life could arise spontaneously from non-living matter is known as:
- ANSWER: Spontaneous Generation
4. Which scientist's experiments with swan-neck flasks finally disproved spontaneous
generation?
- ANSWER: Louis Pasteur
5. The process of using heat to kill most bacteria and delay spoilage in beverages like milk and
wine is called:
- ANSWER: Pasteurization
6. What is the difference between prokaryotic and eukaryotic cells?
- ANSWER: Prokaryotic cells (Bacteria & Archaea) lack a membrane-bound nucleus and other
organelles, while eukaryotic cells (Fungi, Protozoa, Algae) have a true nucleus and membrane-
bound organelles.
7. The three-domain system of classification includes:
- ANSWER: Bacteria, Archaea, and Eukarya.
,8. What type of bond links the sugars and phosphates in the "backbone" of a DNA molecule?
- ANSWER: Phosphodiester bonds
9. The basic unit of a nucleic acid (DNA or RNA) is a:
- ANSWER: Nucleotide
10. What is the function of a ribosome in a cell?
- ANSWER: Protein synthesis (translation).
11. A pure culture contains:
- ANSWER: Only one species or strain of microorganism.
12. What is the purpose of a differential stain, like the Gram stain?
- ANSWER: To distinguish between different types of bacteria based on their staining
properties (e.g., Gram-positive vs. Gram-negative).
13. The Gram stain procedure differentiates bacteria based on differences in their:
- ANSWER: Cell wall structure (peptidoglycan thickness).
14. What is the total magnification when using a 100X objective lens and a 10X ocular lens?
- ANSWER: 1000X
15. Which group of microorganisms is known for having peptidoglycan in their cell walls?
- ANSWER: Bacteria
16. Archaea are often found in extreme environments and differ from bacteria in their:
, - ANSWER: Cell wall composition (lack peptidoglycan) and membrane lipid structure.
17. The term used to describe all of the chemical reactions that occur within a cell is:
- ANSWER: Metabolism
18. What is the primary energy currency of the cell?
- ANSWER: Adenosine Triphosphate (ATP)
19. The Central Dogma of Molecular Biology describes the flow of genetic information as:
- ANSWER: DNA → RNA → Protein
20. A segment of DNA that codes for a functional product (like a protein) is a:
- ANSWER: Gene
21. The process of making an RNA copy from a DNA template is called:
- ANSWER: Transcription
22. The process of synthesizing a protein from an mRNA template is called:
- ANSWER: Translation
23. What is a plasmid?
- ANSWER: A small, circular, double-stranded DNA molecule that is distinct from a cell's
chromosomal DNA, often carrying accessory genes.
24. A change in the nucleotide sequence of DNA is known as a:
- ANSWER: Mutation
Section 1: Fundamentals & History (25 Questions)
1. Who is credited with first observing microorganisms using a simple microscope?
- ANSWER: Antonie van Leeuwenhoek
2. What is the primary purpose of Koch's Postulates?
- ANSWER: To establish a causal relationship between a specific microorganism and a specific
disease.
3. The theory that life could arise spontaneously from non-living matter is known as:
- ANSWER: Spontaneous Generation
4. Which scientist's experiments with swan-neck flasks finally disproved spontaneous
generation?
- ANSWER: Louis Pasteur
5. The process of using heat to kill most bacteria and delay spoilage in beverages like milk and
wine is called:
- ANSWER: Pasteurization
6. What is the difference between prokaryotic and eukaryotic cells?
- ANSWER: Prokaryotic cells (Bacteria & Archaea) lack a membrane-bound nucleus and other
organelles, while eukaryotic cells (Fungi, Protozoa, Algae) have a true nucleus and membrane-
bound organelles.
7. The three-domain system of classification includes:
- ANSWER: Bacteria, Archaea, and Eukarya.
,8. What type of bond links the sugars and phosphates in the "backbone" of a DNA molecule?
- ANSWER: Phosphodiester bonds
9. The basic unit of a nucleic acid (DNA or RNA) is a:
- ANSWER: Nucleotide
10. What is the function of a ribosome in a cell?
- ANSWER: Protein synthesis (translation).
11. A pure culture contains:
- ANSWER: Only one species or strain of microorganism.
12. What is the purpose of a differential stain, like the Gram stain?
- ANSWER: To distinguish between different types of bacteria based on their staining
properties (e.g., Gram-positive vs. Gram-negative).
13. The Gram stain procedure differentiates bacteria based on differences in their:
- ANSWER: Cell wall structure (peptidoglycan thickness).
14. What is the total magnification when using a 100X objective lens and a 10X ocular lens?
- ANSWER: 1000X
15. Which group of microorganisms is known for having peptidoglycan in their cell walls?
- ANSWER: Bacteria
16. Archaea are often found in extreme environments and differ from bacteria in their:
, - ANSWER: Cell wall composition (lack peptidoglycan) and membrane lipid structure.
17. The term used to describe all of the chemical reactions that occur within a cell is:
- ANSWER: Metabolism
18. What is the primary energy currency of the cell?
- ANSWER: Adenosine Triphosphate (ATP)
19. The Central Dogma of Molecular Biology describes the flow of genetic information as:
- ANSWER: DNA → RNA → Protein
20. A segment of DNA that codes for a functional product (like a protein) is a:
- ANSWER: Gene
21. The process of making an RNA copy from a DNA template is called:
- ANSWER: Transcription
22. The process of synthesizing a protein from an mRNA template is called:
- ANSWER: Translation
23. What is a plasmid?
- ANSWER: A small, circular, double-stranded DNA molecule that is distinct from a cell's
chromosomal DNA, often carrying accessory genes.
24. A change in the nucleotide sequence of DNA is known as a:
- ANSWER: Mutation
