biology

Twortvirus

Twortvirus is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Twortvirus rather than just read about it. In short: Twortvirus is a genus of viruses in the family Herelleviridae, in the subfamily Twortvirinae. Bacteria serve as natural hosts.

Key takeaways

Twortvirus belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Twortvirus to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Twortvirus from memory before moving on to harder problems.

Reference excerpt

Twortvirus is a genus of viruses in the family Herelleviridae, in the subfamily Twortvirinae. Bacteria serve as natural hosts. There is only one species in this genus: Staphylococcus phage Twort (Twortvirus twort). Twortvirus is named after English bacteriologist Frederick Twort.

Structure Viruses in this genus are nonenveloped, with a head and tail. The head is approximately 84 nm to 94 nm in diameter and T=16 symmetry. The tail is around 140 nm to 219 nm long, has 6 long terminal fibers, 6 short spikes, globular structures at the tip, and a double base plate. The tail is enclosed in a sheath, which loosens and slides around the tail core upon contraction.

Life cycle Viral replication is cytoplasmic. The virus attaches to the host cell using its tail fibers, and ejects the viral DNA into the host cytoplasm via contraction of its tail sheath. DNA-templated transcription is the method of transcription. Once the viral genes have been replicated, the procapsid is assembled and packed. The tail is then assembled and the mature virions are released via lysis. Bacteria serve as the natural host. Transmission routes are passive diffusion.

History The genus Twortlikevirus was first accepted as a new genus, at the same time as all five of its contained species as well as its containing sub-family Peduovirinae, in ICTV's 2010–11 report. The new genus was proposed in 2009. The genus was renamed to Twortvirus in 2016.

Genome Genomes are linear, around 130-140kb in length. The genome codes for 190 to 215 proteins. Twort's genome is available on NCBI's website. Genomes range between 130k and 149k nucleotides, with 190 to 233 proteins. All complete genomes, as well as several additional "unclassified" virus genomes, are available online.

References

External links ICTV Report: Herelleviridae Viralzone: Twortlikevirus

Worked examples

Example 1 — a first encounter with Twortvirus

Start with the simplest possible case. Write down what Twortvirus claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Twortvirus before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Twortvirus ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Twortvirus

In research: Twortvirus appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Twortvirus in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Twortvirus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Caudovirales, Virus genera, so understanding it makes those chapters shorter.
In everyday life: Look for Twortvirus outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Twortvirus in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Twortvirus means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Twortvirus out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Twortvirus in simple terms?

Twortvirus is a genus of viruses in the family Herelleviridae, in the subfamily Twortvirinae. Bacteria serve as natural hosts.

Why does Twortvirus matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Twortvirus?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Twortvirus.