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IGCSE · Cambridge (CIE) · 0610

Describe a synapse as a junction between neurones

Separate the whole junction from the small gap within it.

Section 14.1 · Coordination and response

Coordination and response pathway · 14.1

Core and Extended; Biology 0610, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked

Before you begin

  • Recall cell membranes, diffusion, sensitivity and the difference between cells, tissues and organs.

Work on paper. Try each question before revealing help, and explain why your method works.

Quick readiness check

How many separate neurones are named in the required synapse definition?

What you will learn

  • Neurones meet at specialised junctions
  • The gap is one part of the synapse

Describe a synapse as a junction between neurones

A synapse is a junction between two neurones. In the chemical model the gap is one part of the whole specialised junction, not its entire definition. Original teaching model.

Neural model reference
FeatureMeaning
Participating cellsTwo separate neurones
ConnectionSynaptic junction
GapSpace between cell regions in the chemical model
InterpretationA connecting line does not mean cell fusion

Neurones meet at specialised junctions

A synapse is a junction between two neurones in the required Core account. It connects communication from one nerve cell with the next in a pathway. The neurones remain separate cells rather than becoming one continuous cell simply because information can pass between them.

In the chemical-synapse model developed in Supplement teaching, the terminal of the first neurone is separated from the next cell by a synaptic gap. The entire junction includes the adjoining specialised cell regions as well as that gap. Synapse should therefore not be defined only as an empty space with no participating cells.

The gap is one part of the synapse

A simple reflex arc includes junctions between its sensory, relay and motor communicating cells. These links allow input to be integrated with output in the supplied pathway. A motor connection to a muscle is a related specialised junction, but this numbered Core requirement specifically asks for a junction between two neurones.

Electrical impulses travel along neurones, while a chemical junction uses neurotransmitter release, diffusion and binding in the Extended account. The Core definition does not require every intermediate mechanism, but it should preserve the two-cell junction idea. A drawn line linking two neurones summarises communication rather than proving their cell membranes are fused into one uninterrupted tube.

Pause and explain

Which is the required definition?

Put the idea to work

Worked example

Define a synapse in the required Core account.

Show the worked solution
  1. Name the junction.
  2. Specify the two participating nerve cells.

Answer A synapse is a junction between two neurones.

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Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.

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From guided practice to a new situation

Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.

1 · Guided

State the required Core definition of a synapse.

Give me a hint

Use junction and two neurones.

Compare my reasoning
  1. It is a communication junction.
  2. The participating cells are two neurones.

A synapse is a junction between two neurones.

Look for these in your work

  • Name a junction
  • Name two neurones
2 · Independent

Distinguish the synaptic gap from the whole chemical synapse.

Give me a hint

The junction also includes specialised parts of the two cells.

Compare my reasoning
  1. The gap is the space between them.
  2. The synapse includes the whole specialised junction.

The synaptic gap is one part of the chemical synapse; the whole junction also involves specialised regions of the two separate neurones.

Look for these in your work

  • Separate gap and junction
  • Retain the two cells
3 · Transfer

A drawing links two neurones with a line. Does this establish that they have fused into one cell?

Give me a hint

A connection can summarise transmission without fusion.

Compare my reasoning
  1. The neurones remain separate.
  2. A synapse links their communication.

No. The line summarises a synaptic connection between separate neurones; it does not establish cell fusion.

Look for these in your work

  • Recognise schematic meaning
  • Keep the two cells separate

Common mistakes

  • Defining the whole synapse only as empty space.
  • Saying the two neurones fuse into one cell.
Recall without your notes

What can you explain now?

Which is the required definition?

Compare with the explanation

Junction between two neurones

It preserves the cell-to-cell connection.

After trying it yourself, choose your next review. This is your self-assessment.

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Make it stick

Define a synapse and distinguish the gap from the complete junction.

If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.

Keep learning Biology

Course scope and assessment

780 sequenced lessons provide 2340 guided, independent and application problems in characteristics, classification, cells, organisation, specimen size, membrane transport, biological molecules, enzymes, plant and human nutrition, plant transport, circulatory systems, the heart, blood vessels, blood, disease transmission, body defences, immunity, gas exchange in humans, respiration energy uses and investigations, aerobic respiration, anaerobic respiration and recovery, excretion in humans, coordination and response, sense organs, hormones, homeostasis, tropic responses, drugs, asexual reproduction, sexual reproduction, sexual reproduction in plants, sexual reproduction in humans, sex hormones in humans, sexually transmitted infections, chromosomes, genes and proteins, mitosis, meiosis, monohybrid inheritance, variation, adaptive features, selection, energy flow, food chains and webs, nutrient cycles, population, community, ecosystem, population-growth phases, food supply, habitat destruction, pollution, conservation, biotechnology and genetic modification. 61 of 61 syllabus sections have linked teaching and staged practice. The earlier inheritance overview remains introductory, and the monohybrid pathway develops the relevant Core and Supplement requirements. This is not full programme completion or guaranteed exam readiness. Written practice is self-checked.

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