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SEMA3F

SEMA3F 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 SEMA3F rather than just read about it. In short: Semaphorin-3F is a protein that in humans is encoded by the SEMA3F gene. The semaphorins are a family of proteins that are involved in signaling.

SEMA3F — main illustration
SEMA3F — illustration

Key takeaways

  • SEMA3F belongs to biology; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect SEMA3F to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of SEMA3F from memory before moving on to harder problems.

Reference excerpt

Semaphorin-3F is a protein that in humans is encoded by the SEMA3F gene. The semaphorins are a family of proteins that are involved in signaling. All the family members have a secretion signal, a 500-amino acid sema domain, and 16 conserved cysteine residues (Kolodkin et al., 1993). Sequence comparisons have grouped the secreted semaphorins into 3 general classes (classes 2, 3 and V), all of which also have an immunoglobulin domain. The semaphorin 3 family, consisting of human semaphorins 3A-G (SEMA3A; MIM 603961), chicken collapsin, and mouse semaphorins 3A-G, all have a basic domain at the C terminus. Chicken collapsin contributes to path finding by axons during development by inhibiting extension of growth cones (Luo et al., 1993) through an interaction with a collapsin response mediator protein of relative molecular mass 62K (CRMP62) (Goshima et al., 1995), a putative homolog of an axonal guidance associated UNC33 gene product (MIM 601168). SEMA3F is a secreted member of the semaphorin III family.[supplied by OMIM]

References

Further reading

Illustrations

SEMA3F illustration
SEMA3F illustration
SEMA3F illustration
SEMA3F illustration
SEMA3F illustration

Worked examples

Example 1 — a first encounter with SEMA3F

Start with the simplest possible case. Write down what SEMA3F 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 SEMA3F 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 SEMA3F 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 SEMA3F

In research
SEMA3F 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 SEMA3F 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
SEMA3F is common in secondary-school and first-year university syllabi. It links to neighbouring topics Genes on human chromosome 3, Human chromosome 3 gene stubs, so understanding it makes those chapters shorter.
In everyday life
Look for SEMA3F 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 SEMA3F in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what SEMA3F means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain SEMA3F out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is SEMA3F in simple terms?

Semaphorin-3F is a protein that in humans is encoded by the SEMA3F gene. The semaphorins are a family of proteins that are involved in signaling.

Why does SEMA3F 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 SEMA3F?

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 SEMA3F.

Tags

  • Genes on human chromosome 3
  • Human chromosome 3 gene stubs

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