Which statement correctly describes the lysogenic cycle of a bacteriophage?
Viral DNA immediately directs host cell lysis after infection
Viral particles are released through budding from the host membrane
Viral RNA remains free in the host cytoplasm without replication
In lysogeny, viral DNA integrates into the host genome as a prophage
The host cell dies immediately following viral attachment
The Correct Answer is D
A. A: Immediate host cell lysis after infection characterizes the lytic cycle, not the lysogenic cycle. In the lytic pathway, viral DNA hijacks host machinery, replicates rapidly, and leads to destruction of the host cell. Lysogeny instead involves a dormant phase without immediate lysis.
B. B: Release of viral particles through budding from the host membrane is typical of enveloped animal viruses, not bacteriophages. Bacteriophages infect bacterial cells and do not use membrane budding as a release mechanism.
C. C: Viral RNA remaining free in the cytoplasm without replication does not describe lysogeny. In bacteriophages, the viral genome is DNA, and during lysogeny it integrates into the bacterial chromosome rather than remaining free and inactive in the cytoplasm.
D. D: In the lysogenic cycle, bacteriophage DNA integrates into the bacterial host genome and becomes a prophage. The viral DNA replicates passively along with the host chromosome during cell division without causing immediate cell death. This allows the virus to persist in a dormant state until conditions trigger entry into the lytic cycle.
E. Both A & E are correct: Immediate host cell death following attachment or infection describes the lytic cycle, not lysogeny. In lysogeny, the host cell survives and continues to replicate while carrying the integrated prophage within its genome.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Gram-negative organisms are characterized by a thin peptidoglycan layer located between the inner cytoplasmic membrane and an outer membrane containing lipopolysaccharide (LPS). The thin peptidoglycan layer is insufficient to retain the crystal violet stain during Gram staining, which is why gram-negative bacteria appear pink after counterstaining with safranin. In contrast, gram-positive bacteria have a thick peptidoglycan layer that retains the crystal violet-iodine complex, appearing purple under a microscope. The thin peptidoglycan and outer membrane structure of gram-negative bacteria also contributes to their increased resistance to certain antibiotics compared to gram-positive organisms
Correct Answer is A
Explanation
A. Cocci, bacilli, coccobacilli, vibrios, spirilla, and spirochetes: These are all recognized bacterial shapes. Cocci are spherical, bacilli are rod-shaped, coccobacilli are short rods, vibrios are comma-shaped, spirilla are rigid spiral-shaped bacteria, and spirochetes are flexible, corkscrew-shaped bacteria. These morphological classifications are used in microbiology to identify and categorize bacterial species.
B. Cocci, diplocytes, flagella, fimbriae, and spores: While cocci are a bacterial shape, diplocytes refers to paired cocci, flagella and fimbriae are appendages, and spores are dormant survival structures. This list mixes shapes with structures, hence does not exclusively describe bacterial morphology.
C. Bacilli, nuclei, ribosomes, mitochondria, and cocci: Bacilli and cocci are bacterial shapes, but nuclei, ribosomes, and mitochondria are cellular organelles not used to define bacterial morphology. Bacteria are prokaryotes and lack membrane-bound organelles.
D. Spirilla, cilia, capsules, and peptidoglycan: Spirilla is a bacterial shape, but cilia are eukaryotic structures, capsules are extracellular protective layers, and peptidoglycan is a cell wall component. Only spirilla refers to bacterial morphology.
E. Spirochetes, lysosomes, peroxisomes, and cocci: Spirochetes and cocci are bacterial shapes, but lysosomes and peroxisomes are eukaryotic organelles. This list is not limited to recognized bacterial morphologies.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.