Viral genomes consist of either DNA or RNA, but never both: True/False

A. A virus consists of a cell wall, ribosomes, and cytoplasm: Viruses are acellular particles and do not possess cellular structures such as a cell wall, ribosomes, or cytoplasm. These components are characteristic of prokaryotic or eukaryotic cells. Viruses lack metabolic machinery and depend entirely on host cells for protein synthesis and energy production.

B. A virus consists of a nucleic acid genome surrounded by a protein capsid and sometimes a lipid envelope: The fundamental structure of a virus includes either DNA or RNA as its genetic material enclosed within a protein capsid. Some viruses also possess a lipid envelope derived from the host cell membrane during budding.

C. A virus contains a nucleus and membrane-bound organelles: A nucleus and organelles such as mitochondria or endoplasmic reticulum are defining features of eukaryotic cells. Viruses lack internal cellular organization and do not contain membrane-bound organelles.

D. A virus is composed entirely of lipopolysaccharide and protein: Lipopolysaccharide is a component of the outer membrane of Gram-negative bacteria, not viruses. Viral structure is defined by nucleic acid and a protein capsid, with some viruses also containing a lipid envelope derived from host membranes.

A. Nucleus: The nucleus contains the cell’s genetic material and controls transcription and replication. While nuclear damage can affect gene expression and cell survival, it does not directly explain the acute loss of ion gradients and cellular lysis caused by disruption of membrane integrity.

B. Cell membrane: The cell membrane, composed of a phospholipid bilayer with embedded proteins, maintains selective permeability, ion gradients, and cellular homeostasis. Disruption of the membrane compromises the barrier between intracellular and extracellular environments, causing uncontrolled ion flux, osmotic imbalance, and eventual cell lysis.

C. Ribosome: Ribosomes are responsible for protein synthesis, translating mRNA into polypeptides. Impaired ribosomal function affects protein production but does not immediately cause loss of ion gradients or membrane rupture.

D. Cytoskeleton: The cytoskeleton provides structural support, intracellular transport, and shape maintenance. While damage to cytoskeletal elements can affect cell morphology and motility, it does not directly cause ion imbalance or lysis due to phospholipid bilayer disruption.

E. Golgi apparatus: The Golgi apparatus modifies, sorts, and packages proteins and lipids for secretion or intracellular use. Dysfunction here affects protein processing and trafficking but does not directly compromise membrane integrity or lead to immediate lysis.