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Microbiology Final Exam Jersey College
VERSION 1 QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS
RATIONALES 2025
- What structure do bacteria use to move? A. Ribosomes B. Pili C. Flagella D. Capsule Flagella are tail-like structures that rotate to allow motility in bacteria.
- Which stain is used to differentiate bacterial species into Gram- positive and Gram-negative? A. Acid-fast stain B. Capsule stain C. Endospore stain
D. Gram stain The Gram stain differentiates based on cell wall composition: peptidoglycan-rich walls retain crystal violet (Gram-positive).
- Which of the following organisms is a prokaryote? A. Escherichia coli B. Saccharomyces cerevisiae C. Amoeba proteus D. Giardia lamblia E. coli is a bacterium and lacks a nucleus, classifying it as a prokaryote.
- What type of microorganism causes tuberculosis? A. Virus B. Fungus C. Bacterium D. Protozoan Mycobacterium tuberculosis is a bacterium responsible for tuberculosis.
- Which part of the bacterial cell is targeted by penicillin? A. Ribosome B. Cell wall C. Plasma membrane D. Nucleoid
- What kind of immunity results from vaccination? A. Natural active B. Natural passive C. Artificial passive D. Artificial active Vaccines stimulate the immune system to produce antibodies, which is artificial active immunity.
- What is the function of an endospore in bacteria? A. Energy production B. Survival under harsh conditions C. DNA replication D. Antibiotic resistance Endospores are dormant structures that help bacteria survive extreme conditions.
- Which organism is known for causing strep throat? A. Staphylococcus aureus B. Escherichia coli C. Streptococcus pyogenes D. Neisseria meningitidis Streptococcus pyogenes is the causative agent of strep throat.
- What type of microscope provides the highest magnification and resolution? A. Compound light microscope
B. Dark-field microscope C. Phase-contrast microscope D. Electron microscope Electron microscopes use electrons instead of light and can achieve much higher resolution.
- What enzyme is used by retroviruses to convert RNA into DNA? A. DNA polymerase B. RNA polymerase C. Reverse transcriptase D. Ligase Reverse transcriptase allows retroviruses to synthesize DNA from RNA templates.
- Which of the following is an example of a DNA virus? A. HIV B. Influenza C. Herpes simplex virus D. SARS-CoV- 2 Herpes simplex virus contains double-stranded DNA as its genetic material.
- What term describes the presence of bacteria in the blood? A. Bacteremia B. Sepsis C. Septicemia
B. Latent infection C. Opportunistic infection D. Chronic infection Nosocomial infections are hospital-acquired infections.
- What type of hypersensitivity reaction is anaphylaxis? A. Type II B. Type III C. Type I D. Type IV Type I hypersensitivity is immediate and includes anaphylaxis due to IgE-mediated release of histamine.
- Which of the following is a dimorphic fungus? A. Penicillium B. Histoplasma capsulatum C. Candida albicans D. Aspergillus Histoplasma capsulatum can exist as both mold and yeast depending on temperature.
- The complement system is part of: A. Adaptive immunity B. Innate immunity C. Passive immunity D. Artificial immunity
The complement system enhances phagocytosis and lysis and is part of innate immunity.
- Which structure allows bacteria to transfer DNA during conjugation? A. Capsule B. Pilus C. Flagellum D. Ribosome The sex pilus is involved in the transfer of genetic material during conjugation.
- Which class of antibody is found in secretions such as saliva and breast milk? A. IgG B. IgM C. IgA D. IgE IgA provides mucosal immunity and is abundant in secretions.
- What process kills all forms of microbial life, including spores? A. Disinfection B. Antisepsis C. Sanitization D. Sterilization Sterilization eliminates all forms of microbial life, including spores.
B. Mutualism C. Commensalism D. Opportunism In mutualism, both organisms benefit from the association.
- What is the primary mode of transmission for the hepatitis B virus? A. Oral-fecal B. Bloodborne C. Respiratory droplets D. Vector-borne Hepatitis B is transmitted through blood and bodily fluids.
- What structure in a virus is responsible for host recognition? A. Spike protein B. Capsid C. Envelope D. Core Spike proteins on the virus surface bind to specific receptors on host cells.
- What is the first antibody produced during an infection? A. IgA B. IgM C. IgE
D. IgG IgM is the first antibody produced in a primary immune response.
- Which bacterium is most commonly associated with antibiotic- associated colitis? A. E. coli B. Salmonella C. Clostridium difficile D. Vibrio cholerae C. difficile overgrows when normal gut flora is disrupted by antibiotics.
- What does “selective toxicity” mean in antimicrobial therapy? A. Harms the microbe but not the host B. Kills all microbes and host cells C. Targets host cells only D. Targets toxins Selective toxicity refers to drugs that inhibit or kill the pathogen without harming the host.
- What lab test is used to determine antibiotic sensitivity? A. ELISA B. Kirby-Bauer disk diffusion C. Gram stain D. Widal test
B. Lyophilization C. Freezing at 4°C D. Drying Lyophilization (freeze-drying) preserves microorganisms for long- term storage.
- Which of the following is a helminth? A. Entamoeba B. Trichomonas C. Ascaris D. Plasmodium Ascaris is a parasitic roundworm, classified as a helminth.
- What is the outermost layer of a Gram-negative bacterium? A. Peptidoglycan B. Outer membrane C. Plasma membrane D. Capsule Gram-negative bacteria have an outer membrane containing lipopolysaccharides.
- Which disease is caused by a prion? A. Influenza B. Rabies C. Creutzfeldt-Jakob disease D. Hepatitis
Prions cause neurodegenerative diseases like CJD by misfolding proteins in the brain.
- What is the portal of entry for Mycobacterium tuberculosis? A. Respiratory tract B. Gastrointestinal tract C. Skin D. Urogenital tract M. tuberculosis enters the body through inhalation into the lungs.
- The term “aseptic technique” refers to: A. Killing all microbes B. Preventing contamination C. Sterilizing instruments D. Applying disinfectants Aseptic technique prevents contamination of sterile areas during procedures.
- What is the genome of HIV composed of? A. Single-stranded DNA B. Double-stranded DNA C. Double-stranded RNA D. Single-stranded RNA HIV has a single-stranded RNA genome and uses reverse transcriptase to replicate.
C. Fungi from protozoa D. Anaerobes from aerobes Staphylococci produce catalase, while streptococci do not.
- Which immunoglobulin is involved in allergic reactions? A. IgG B. IgA C. IgM D. IgE IgE binds to mast cells and basophils, triggering histamine release during allergic reactions.
- Which method is most effective for sterilizing surgical instruments? A. Boiling B. Autoclaving C. Alcohol wipe D. Freezing Autoclaving uses pressurized steam to sterilize and kill all forms of microbial life, including spores.
- What part of the immune system is primarily responsible for destroying virus-infected cells? A. B lymphocytes B. Cytotoxic T lymphocytes C. Helper T cells
D. Plasma cells Cytotoxic T cells recognize and destroy infected host cells displaying viral antigens.
- Which bacterium causes tetanus? A. Bacillus anthracis B. Clostridium tetani C. Clostridium botulinum D. Salmonella typhi Clostridium tetani releases a neurotoxin that causes muscle rigidity and spasms.
- Which enzyme helps HIV integrate its DNA into the host genome? A. Reverse transcriptase B. Protease C. Integrase D. Ligase Integrase inserts viral DNA into the host cell’s DNA, allowing replication.
- What disease does Treponema pallidum cause? A. Gonorrhea B. Chlamydia C. Syphilis
Selective media contain substances that inhibit the growth of some organisms while allowing others to grow.
- Which organism is known to cause fungal vaginitis? A. Trichomonas vaginalis B. Neisseria gonorrhoeae C. Candida albicans D. Treponema pallidum Candida albicans is a yeast that can overgrow in moist areas and cause candidiasis.
- What is the term for a microorganism that does not normally cause disease but can become pathogenic in a compromised host? A. Commensal B. Opportunistic C. Symbiont D. Saprobe Opportunistic pathogens cause disease when the host’s immune defenses are weakened.
- What type of bacteria is used in the production of yogurt? A. Clostridium B. Bacillus C. Lactobacillus D. Salmonella
Lactobacillus ferments lactose, producing lactic acid that thickens milk into yogurt.
- Which virus is associated with cervical cancer? A. Herpes simplex virus B. Human papillomavirus C. Hepatitis C D. Epstein-Barr virus HPV, especially types 16 and 18, is linked to cervical dysplasia and cancer.
- Which of the following can cross the placenta and cause congenital infections? A. Rhinovirus B. Cytomegalovirus C. Norovirus D. Rotavirus CMV can cross the placenta and result in congenital defects in newborns.
- Which chemical is most effective as a disinfectant for skin before surgery? A. Alcohol B. Hydrogen peroxide C. Chlorhexidine D. Formalin
