BIO 201 Microbiology Midterm Exam Review | Actual Exam Questions with Complete Questions, Verified Correct Answers and Detailed Rationales | Latest Update 2026/2027 | Jersey College – Already Graded A+

BIO 201 Microbiology Midterm Exam Review | Actual
Exam Questions with Complete Questions, Verified
Correct Answers and Detailed Rationales | Latest Update
2026/2027 | Jersey College – Already Graded A+


Question 1
Bacteria that appear red after Gram staining are said to be gram ______.
A. Zero
B. Positive
C. Neutral
D. Negative
Answer: D
Rationale: Gram-negative bacteria do not retain the crystal violet stain and appear
red/pink after counterstaining with safranin.


Question 2
The destruction of all microorganisms and their endospores is referred to as:
A. Sanitation
B. Disinfection
C. Sterilization
D. Antisepsis
Answer: C
Rationale: Sterilization is the complete destruction of all microorganisms, including
endospores.


Question 3
Which of the following is a systemic autoimmune disease?
A. Rheumatoid arthritis
B. Gout
C. Gouty arthritis
D. Osteoarthritis
Answer: A
Rationale: Rheumatoid arthritis is a systemic autoimmune disease affecting multiple
joints and other organs.



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,Question 4
How many electrons can the outermost shell of an atom hold?
A. 6
B. 4
C. 8
D. 10
Answer: C
Rationale: The outermost shell of an atom can hold up to 8 electrons (octet rule).


Question 5
Toxoplasma gondii belongs to which group of eukaryotic organisms?
A. Helminths
B. Fungi
C. Protozoans
D. Algae
Answer: C
Rationale: Toxoplasma gondii is a protozoan parasite.


Question 6
Staphylococci and streptococci are best classified in the group of:
A. Gram-positive cocci
B. Gram-negative cocci
C. Gram-negative aerobic rods and cocci
D. Anaerobic gram-negative cocci
Answer: A
Rationale: Staphylococci and streptococci are both gram-positive cocci.


Question 7
A saucer-shaped liquefaction of gelatin stabs is said to have a(n) ______ appearance.
A. Circle
B. Flat
C. Crateriform
D. Folded
Answer: C
Rationale: Crateriform describes a saucer-shaped liquefaction pattern in gelatin stab
cultures.



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,Question 8
Which of the following is not found in all bacterial cells?
A. Plasma membrane
B. DNA
C. Capsule
D. Ribosomes
Answer: C
Rationale: Capsules are not present in all bacterial cells; they are an optional
structure.


Question 9
Enzymes that attack the peptidoglycan layer of bacteria and are present in perspiration,
nasal secretion, saliva, and tears are ______.
A. Lipases
B. Proteases
C. Lysozymes
D. Amylases
Answer: C
Rationale: Lysozymes are enzymes that break down the peptidoglycan layer of
bacterial cell walls.


Question 10
The effectiveness of a drug against a microbe is also referred to as the drug's ______.
A. Toxicity
B. Potency
C. Stability
D. Efficacy
Answer: D
Rationale: Efficacy refers to the effectiveness of a drug against a microbe.


Question 11
A virus that infects bacteria is referred to as a(n) ______.
A. Virus
B. Antigen
C. Bacteriophage
D. Infection
Answer: C
Rationale: A bacteriophage is a virus that infects bacteria.
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, Question 12
Complex communities of microorganisms on surfaces are called:
A. Biofilms
B. Biospheres
C. Flora
D. Colonies
Answer: A
Rationale: Biofilms are complex communities of microorganisms attached to surfaces.


Question 13
Which of the following is likely to be the most frequently used portal of entry?
A. Genitourinary tract
B. Intestinal tract
C. Urinary tract
D. Respiratory tract
Answer: D
Rationale: The respiratory tract is the most frequently used portal of entry for
pathogens.


Question 14
Microorganisms that acquire energy from light are called:
A. Ameba
B. Plants
C. Bacteria
D. Phototrophs
Answer: D
Rationale: Phototrophs are organisms that obtain energy from light.


Question 15
The technique that combines freezing and drying to preserve microbes and other cells is:
A. Pasteurization
B. Ionizing radiation
C. Desiccation
D. Lyophilization
Answer: D
Rationale: Lyophilization (freeze-drying) is used to preserve microbes and other cells.

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