Lytic life cycle of phages does not include

Correct Answer: A

Rationale: The correct answer is A: germination. In the lytic life cycle of phages, germination is not a stage. The lytic cycle involves adsorption, penetration, replication, assembly, and lysis. Germination is typically associated with the lysogenic cycle, where the phage DNA integrates into the host genome. Therefore, A is the correct answer. Choices B, C, and D are incorrect because they are all stages of the lytic cycle. Penetration refers to the injection of phage DNA into the host cell, adsorption is the attachment of the phage to the host cell, and lysis is the final stage where the host cell bursts, releasing new phages.

Correct Answer: A

Rationale: The correct answer is A: Cell wall. Mycoplasma species lack a cell wall, making them unique among bacteria. This is because they have a flexible cell membrane that provides structural support instead of a rigid cell wall. The absence of a cell wall allows them to be pleomorphic and gives them resistance to certain antibiotics targeting cell wall synthesis. Plasma membrane (B), DNA (C), and ribosomes (D) are present in Mycoplasma species, so they are not the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Helicobacter pylori. This bacterium is the most likely causative agent of gastric ulcers. Here's the rationale: 1. Helicobacter pylori is commonly associated with gastric ulcers. 2. It is a gram-negative bacterium that grows on chocolate agar and is oxide reductase-positive. 3. The slow growth on the fifth day is characteristic of H. pylori. 4. Campylobacter jejuni and Campylobacter fetus are not typically associated with gastric ulcers. 5. Mycoplasma hominis is a bacterium that lacks a cell wall and is not commonly found in gastric ulcers.

Correct Answer: B

Rationale: The correct answer is B: Vibrio cholerae. Cholera is caused by Vibrio cholerae, a bacterium that produces a toxin leading to severe diarrhea and dehydration. Clostridium botulinum (A) causes botulism, Salmonella enterica (C) causes salmonellosis, and Escherichia coli (D) can cause various illnesses but not cholera. Vibrio cholerae is the only bacteria specifically known for causing cholera.

Correct Answer: C

Rationale: The correct answer is C: heterotrophic. Fungi are heterotrophic organisms that obtain nutrients by absorbing organic compounds from their environment. They do not produce their own food through photosynthesis (option A: autotrophic) or chemosynthesis (option B: chemotrophic). Fungi also do not rely on light for energy (option D: phototrophic). Therefore, the correct choice is C as it accurately describes the nutritional mode of fungi.