Question

How do viruses collect and use energy?

Answer 1

Short answer: viruses do not have their own metabolism or “power plants.” They don’t collect fuel or make ATP the way cells do. Instead they steal energy and building blocks from the cells they infect and (in some cases) carry a few tools or genes that help keep the host’s energy-producing systems running long enough to make new viruses.

How this works, in more detail

- No independent metabolism
- A typical virus particle (virion) has no intact metabolic pathways and cannot generate ATP or reduce cofactors. Viruses do not have mitochondria, chloroplasts, or complete glycolytic/TCA pathways.

- Using host energy and machinery
- Once inside a cell a virus relies on host ATP and metabolic pools to power:
- genome replication (DNA/RNA synthesis),
- transcription,
- translation (protein synthesis),
- assembly and maturation of new virions,
- intracellular transport (movement along microtubules by host motor proteins uses ATP),
- membrane rearrangements or budding (requires host machinery/ATP).
- Many viral proteins themselves are ATPases or use ATP (for example bacteriophage packaging motors that use ATP to pump viral DNA into capsids), but the ATP they hydrolyze was produced by the host cell.

- Hijacking and reprogramming host metabolism
- Viruses commonly rewire host metabolism to increase the supply of nucleotides, amino acids, lipids and ATP. Typical changes include increased glucose uptake and glycolysis, enhanced nucleotide biosynthesis and increased lipid synthesis (important for enveloped viruses).
- Examples:
- Cytomegalovirus (HCMV) and some other large DNA viruses stimulate glycolysis and fatty-acid synthesis to provide membranes and energy.
- Influenza and many RNA viruses increase glycolysis and alter mitochondrial function to favor production of building blocks.
- SARS‑CoV‑2 infection shifts cellular metabolism toward glycolysis in some cell types.

- Viral “auxiliary” genes that influence energy production
- Some bacteriophages (especially cyanophages that infect photosynthetic bacteria) carry auxiliary metabolic genes (AMGs) such as psbA/psbD (photosystem II proteins) that help keep host photosynthesis working during infection so the cell continues to make ATP and reductant for viral production.
- Marine viruses have been found that encode light-driven ion pumps (rhodopsins) or other proteins that can influence host proton gradients or light harvesting — these can affect energy flows in host cells.
- Some phages encode enzymes involved in nucleotide biosynthesis (e.g., ribonucleotide reductases) to boost dNTP pools.

- Energy-demanding steps where viruses directly use energy
- Genome packaging motors in many dsDNA phages hydrolyze ATP to translocate DNA into capsids.
- Viral uncoating, disassembly, and some remodeling steps use host ATP-dependent chaperones or AAA+ ATPases.

Bottom line
Viruses don’t “collect” energy themselves; they exploit host energy production and biochemical pathways, and some carry genes that help preserve or redirect host energy generation to favor viral replication. If you want, I can give more details on any of the examples (e.g., cyanophages and photosynthesis genes, how phage packaging motors work, or how specific human viruses reprogram host metabolism).