What is the role of bacterial enzymes like amylase and protease?

Correct Answer: C

Rationale: The correct answer is C because bacterial enzymes like amylase and protease catalyze biochemical reactions like digestion. Amylase breaks down carbohydrates, while protease breaks down proteins. This process is essential for bacterial metabolism and nutrient acquisition. Choice A (Break down toxins) is incorrect because bacterial enzymes are primarily involved in nutrient breakdown, not toxin degradation. Choice B (Facilitate movement) is incorrect as enzymes are not directly involved in bacterial movement. Choice D (Promote spore formation) is incorrect because enzymes like amylase and protease are not directly involved in spore formation.

Correct Answer: C

Rationale: The correct answer is C: tapeworms. Taeniasis is specifically caused by tapeworms of the Taenia species, such as Taenia solium. These parasitic worms infect the intestines of humans through consumption of contaminated food or water. Ringworms (choice A), hookworms (choice B), and pinworms (choice D) are all different types of parasites that cause distinct infections in the body, not taeniasis. Tapeworms are the only organisms among the choices that are directly associated with taeniasis due to their unique life cycle and mode of infection.

Correct Answer: A

Rationale: The correct answer is A: The lysozyme hydrolyzes the glycoside bonds between the N-acetylmuramic acid and the N-acetylglucosamine in the peptidoglycan of the cell wall. This is because lysozyme is an enzyme that specifically targets the peptidoglycan layer of bacterial cell walls, breaking down the structure by cleaving the glycosidic bonds between these two specific sugar molecules. This action weakens the cell wall, leading to bacterial cell lysis. The other choices are incorrect because lysozyme does not target phosphate bonds in phospholipids (B), disulfide bonds in immunoglobulins (C), or hydrogen bonds in bacterial capsules (D).

Correct Answer: A

Rationale: The correct answer is A: Bacterial ribosomes synthesize proteins. Ribosomes are cellular organelles responsible for protein synthesis by translating mRNA into amino acids. They are essential for the production of proteins needed for cell function. Choices B, C, and D are incorrect because ribosomes do not synthesize DNA, degrade toxic substances, or assist in cell division. DNA synthesis is carried out by DNA polymerase, degradation of toxic substances is typically done by enzymes, and cell division is primarily regulated by the cell cycle machinery.

Correct Answer: B

Rationale: The correct answer is B because humoral immunity involves the formation of specific antibodies by B cells. B cells differentiate into plasma cells that produce antibodies to target specific antigens. T cells are involved in cell-mediated immunity, not humoral immunity. Choice A is incorrect because T cells do not produce antibodies. Choice C is incorrect as only B cells are responsible for antibody production in humoral immunity. Choice D is incorrect as B cells play a crucial role in the humoral immune response.

Correct Answer: D

Rationale: The correct answer is D, "All of the above," because all three bacteria (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) can cause urinary tract infections. E. coli is the most common causative agent of UTIs, followed by Staphylococcus aureus and occasionally Pseudomonas aeruginosa. Each of these bacteria has different virulence factors that enable them to infect the urinary tract. Therefore, it is important to consider all three options when diagnosing and treating UTIs. Choices A, B, and C are incorrect because each of those bacteria can individually cause UTIs, so the correct answer is D, as it encompasses all the possible causative agents.

Correct Answer: C

Rationale: Step 1: Define sexually transmitted infections (STIs) as infections primarily spread through sexual contact. Step 2: Understand that STIs can also be transmitted through non-sexual means like blood transfusions. Step 3: Recognize that choice C is incorrect as it limits STIs to only sexually transmitted infections. Step 4: Therefore, the correct answer is C as it does not encompass all possible modes of transmission for STIs. Summary: Choices A, B, and D are incorrect as they all accurately describe the characteristics of sexually transmitted infections, while choice C is incorrect as it excludes other potential modes of transmission for STIs.

Correct Answer: A

Rationale: The correct answer is A. Method of Ziel-Neelsen. This method uses a special stain (carbol fuchsin) to detect acid-fast organisms like Mycobacterium tuberculosis, the causative agent of tuberculosis. The staining procedure involves heating the slide to help penetrate the mycolic acid layer of the bacteria, making them resistant to decolorization by acid-alcohol. The red stained acid-fast bacilli stand out against the blue counterstain. This method is specific for identifying tubercle bacilli in sputum samples. Choice B: Method of Romanowsky-Giemsa is used for staining blood smears and is not suitable for detecting acid-fast bacilli in sputum. Choice C: Method of Gram is used for staining bacteria based on their cell wall composition and is not effective for identifying acid-fast bacilli like Mycobacterium tuberculosis. Choice D: Method of Neisser is not a specific staining method for acid-fast bacilli and is not suitable

Correct Answer: A

Rationale: Saddle nose is a condition where the bridge of the nose collapses, a characteristic feature of congenital syphilis. This occurs due to inflammation and destruction of cartilage. Syphilis is caused by the bacterium Treponema pallidum. CMV, Rubella, and Toxoplasmosis do not typically cause saddle nose. CMV can result in hearing loss, Rubella can lead to cataracts and heart defects, and Toxoplasmosis may cause hydrocephalus or chorioretinitis.