All Free Veterinary Science MCQs with Answers
Every Veterinary Science question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
758 questions · page 23 of 38
- A. C1q
- B. C3b
- C. C5a
- D. C9
Explanation: C3b binds to microbial surfaces and promotes their recognition and phagocytosis by immune cells.
Correct answer: C3b- A. Mannose on a microbial surface
- B. Bacterial lipopolysaccharide alone
- C. Antigen-bound antibody
- D. Spontaneous C3 hydrolysis
Explanation: The classical pathway begins when C1 binds to antibody, usually IgM or IgG, attached to an antigen.
Correct answer: Antigen-bound antibody- A. Basophils
- B. Erythrocytes
- C. Naive B cells
- D. Natural killer cells
Explanation: Natural killer cells bind the Fc portion of target-bound IgG through CD16 and then release cytotoxic granules.
Correct answer: Natural killer cells444. Which culture medium is commonly used for the isolation of dermatophytes from animal skin and hair?
- A. Sabouraud dextrose agar
- B. MacConkey agar
- C. Lowenstein-Jensen medium
- D. Thayer-Martin medium
Explanation: Sabouraud dextrose agar is acidic and supports the growth of fungi, including dermatophytes.
Correct answer: Sabouraud dextrose agar- A. Destroy vaccine antigen rapidly
- B. Enhance and prolong the immune response
- C. Replace the need for antigen
- D. Prevent all local inflammation
Explanation: Adjuvants improve antigen presentation and stimulate a stronger, longer-lasting immune response to nonreplicating vaccine antigens.
Correct answer: Enhance and prolong the immune response- A. Ribosome
- B. Flagellum
- C. Capsule
- D. Plasmid
Explanation: A capsule can prevent effective attachment and engulfment by phagocytic cells, increasing bacterial survival in tissues.
Correct answer: Capsule447. Which condition is commonly used for sterilizing heat-stable laboratory instruments in an autoclave?
- A. 100°C at normal pressure
- B. 80°C at reduced pressure
- C. 160°C with dry air
- D. 121°C at 15 psi
Explanation: Steam under pressure at about 121°C and 15 psi destroys vegetative bacteria, viruses, fungi, and bacterial spores when applied for…
Correct answer: 121°C at 15 psi- A. Neutralize microbes at mucosal surfaces
- B. Activate red blood cell production
- C. Cause systemic mast-cell degranulation
- D. Destroy infected cells through complement
Explanation: Secretory IgA binds microbes and toxins at mucosal surfaces, limiting their attachment and entry without causing extensive inflammation.
Correct answer: Neutralize microbes at mucosal surfaces- A. Lipopolysaccharide
- B. Calcium dipicolinate
- C. Hyaluronic acid
- D. Teichoic acid
Explanation: Calcium dipicolinate, together with the dehydrated spore core, contributes substantially to the exceptional resistance of bacterial…
Correct answer: Calcium dipicolinate- A. Immediate IgE-mediated allergy
- B. Circulating bacterial endotoxin
- C. Delayed cellular hypersensitivity
- D. Neutralizing serum antibody
Explanation: The tuberculin test measures a delayed-type cellular immune response to mycobacterial antigens, usually becoming evident after local skin…
Correct answer: Delayed cellular hypersensitivity- A. Binary fission
- B. Transduction
- C. Transformation
- D. Conjugation
Explanation: Conjugation transfers DNA, commonly through a pilus, from a donor bacterium to a recipient in direct contact.
Correct answer: Conjugation- A. Memory B and T lymphocytes
- B. Mature erythrocytes
- C. Neutrophil granules
- D. Plasma complement proteins
Explanation: Antigen exposure produces memory B and T cells that persist after the initial response and react rapidly upon later exposure.
Correct answer: Memory B and T lymphocytes- A. Coagulase test
- B. Agglutination test
- C. Oxidase test
- D. Catalase test
Explanation: Agglutination tests detect visible clumping produced when antibodies cross-link particulate antigens.
Correct answer: Agglutination test- A. Canine infectious hepatitis
- B. Canine parvoviral enteritis
- C. Canine distemper
- D. Canine adenovirus cough
Explanation: Canine distemper virus can cause respiratory and gastrointestinal disease, neurological signs, and hyperkeratosis of the footpads.
Correct answer: Canine distemper- A. Replicate rapidly in host tissues
- B. Cannot be recognized by antibodies
- C. Always cause severe local disease
- D. Provide weaker stimulation of cellular immunity
Explanation: Killed organisms cannot replicate and often produce a weaker or shorter immune response, so an adjuvant can enhance antigen presentation…
Correct answer: Provide weaker stimulation of cellular immunity- A. Mycoplasma
- B. Corynebacterium
- C. Bordetella
- D. Erysipelothrix
Explanation: Mycoplasma species lack the peptidoglycan cell wall targeted by penicillin and related beta-lactam drugs.
Correct answer: Mycoplasma- A. Ziehl-Neelsen staining
- B. India ink preparation
- C. Albert staining
- D. Giemsa staining
Explanation: India ink provides a dark background against which the unstained capsule appears as a clear halo around the bacterial cell.
Correct answer: India ink preparation- A. Escherichia coli
- B. Salmonella enterica
- C. Listeria monocytogenes
- D. Staphylococcus aureus
Explanation: Listeria monocytogenes displays tumbling motility at room temperature because of its temperature-dependent flagellar activity.
Correct answer: Listeria monocytogenes- A. Detergents remove their capsid genes
- B. Detergents destroy their viral DNA
- C. Detergents block their ribosomes
- D. Detergents disrupt their lipid envelope
Explanation: The envelope is a lipid membrane that is disrupted by detergents, causing loss of viral infectivity.
Correct answer: Detergents disrupt their lipid envelope- A. Cat
- B. Dog
- C. Sheep
- D. Horse
Explanation: Felids, including domestic cats, are the definitive hosts in which Toxoplasma gondii undergoes sexual reproduction and produces oocysts.
Correct answer: Cat