Semiconservative replication refers to

Both facilitated diffusion and active transport require carrier proteins to move substances across the plasma membrane, but the mechanisms differ. Facilitated diffusion uses carrier or channel proteins to transport molecules down their concentration gradient without energy expenditure. In contrast, active transport also uses carrier proteins but moves substances against their concentration gradient, requiring energy input, usually from ATP hydrolysis. These proteins provide specificity for particular molecules and enable transport that cannot occur through simple diffusion, ensuring that cells can regulate nutrient uptake, ion balance, and waste removal efficiently.

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A. Budding or exocytosis: Enveloped viruses acquire their lipid envelope from the host cell membrane during exit. This process occurs via budding, where the viral capsid pushes through the host cell’s plasma membrane, incorporating host lipids into the viral envelope, or via exocytosis, where the virus is transported in vesicles and released without immediately lysing the cell. This allows the host cell to remain viable for a period, facilitating viral production.

B. Rupturing the virus: Viruses themselves do not rupture; they rely on host cell processes for replication and exit. Rupturing the viral particle would destroy the virus, so this is not a method of viral release.

C. Endocytosis: Endocytosis is a mechanism by which host cells internalize viruses, not a method for viral exit. Viruses enter cells through endocytosis to initiate infection but leave through budding or exocytosis.

D. Bursting the host cell: Lysis or bursting is a common exit strategy for non-enveloped viruses but not for enveloped viruses. Enveloped viruses avoid immediate lysis to preserve the host membrane needed for their lipid envelope, allowing for more controlled release.