--- title: "Virus Structure and Classification by Genome Type" description: "A virus is a genome in a protein coat, sometimes wrapped in a membrane taken from a host. Grouping viruses by whether the genome is DNA or RNA, single or double stranded, and which way it reads predic" canonical: https://lightmysky.com/learn/science/virus-structure-and-classification-by-genome-type-mt_u2-ecQEwwn source: https://lightmysky.com/learn/science/virus-structure-and-classification-by-genome-type-mt_u2-ecQEwwn.md retrieved: 2026-09-12 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Virus Structure and Classification by Genome Type A virus is a genome in a protein coat, sometimes wrapped in a membrane taken from a host. Grouping viruses by whether the genome is DNA or RNA, single or double stranded, and which way it reads predicts what has to happen first inside the cell. Subject: Science · Area: Microbiology · Ages 19 to 20 Page: https://lightmysky.com/learn/science/virus-structure-and-classification-by-genome-type-mt_u2-ecQEwwn ## Ready when they can - Works out the first step a virus must take from its genome type. - Explains why an envelope changes how a virus enters and how it survives outside. - Says why viruses are not counted as cells, using two specific criteria. ## Lesson: Read the genome, predict the first move Picture a parcel of genes in a protein shell, at times wrapped in a stolen membrane coat. Inside sits DNA or RNA, never both, in single or double strands that read forward or backward. Shape and wrapper finish the portrait, but the genome writes the life story. Now you can predict the opening move from that genome. Double DNA gets read at once, while single DNA must be doubled first. Plus strands translate straight away like ready made notes, but minus strands must be copied into readable form first. The RNA to DNA stitcher converts its RNA, then joins the host genome for a lasting stay. **Example.** Next, watch the wrapper change the journey. Wrapped particles blend with host membranes on entry, yet dry out and fall apart outside, so they need close contact to spread. Bare particles break in more directly and survive longer in the open. Entry style and toughness both follow the coat. **Tip.** Finally, run the two cell tests yourself. Viruses show order and carry genes, but they run no metabolism and cannot split on their own. Every one of them must attach, enter, uncoat, copy, assemble, and escape using a host. That dependence is why they are not counted as cells. **Recap.** You read the genome type to predict the first move every virus must make. ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Metabolic Diversity: Choosing an Electron Donor and Acceptor](https://lightmysky.com/learn/science/metabolic-diversity-choosing-an-electron-donor-and-acceptor-mt__2yCr9OSIn) ## Opens up - [Viral Life Cycles: Lysis, Lysogeny and Latency](https://lightmysky.com/learn/science/viral-life-cycles-lysis-lysogeny-and-latency-mt_OI8-dySb5A)