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IGCSE · Cambridge (CIE) · 0610

Identify vesicles gap and receptors in a published synapse image

Translate the unchanged source labels into the syllabus structures.

Coordination and response pathway · 14.1

Extended only (Supplement); 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

What does Synaptic cleft name in this source?

What you will learn

  • Read the enlarged axon-terminal view
  • Separate the source illustration from a scale measurement

Identify vesicles gap and receptors in a published synapse image

Published chemical synapse illustration with vesicles in the upper presynaptic axon terminal, green neurotransmitter molecules, cleft and receptor-bearing channels on the lower postsynaptic membrane.
OpenStax Anatomy and Physiology · Young et al., version 8.25 (2016) · CC BY 4.0 · Original licence record · Source image unchanged; displayed responsively. Open full-size image

Unchanged OpenStax chemical-synapse illustration. Cleft means gap; receiving receptor-bearing channels are shown on the postsynaptic membrane. The inset arrow indicates enlargement.

Enlarge image for inspection

Scroll across the source to trace its leaders and gap bracket. Try identification before opening the key.

Published chemical synapse illustration with vesicles in the upper presynaptic axon terminal, green neurotransmitter molecules, cleft and receptor-bearing channels on the lower postsynaptic membrane.
Check the identification key

Synaptic vesicles: round compartments within the upper terminal. Neurotransmitters: green particles in vesicles and cleft. Synaptic cleft: gap between membranes. Ligand-gated channels with receptors for neurotransmitters: turquoise receptor-bearing proteins on the lower postsynaptic membrane. The grey inset arrow marks enlargement, not an electrical impulse crossing the gap.

Read the enlarged axon-terminal view

The published OpenStax image shows an enlarged chemical synapse. The upper bulb is labelled Axon terminal and belongs to the presynaptic neurone. The lower receiving cell is labelled Postsynaptic neuron. The small whole-cell inset and grey magnification arrow locate the enlarged detail; that broad arrow is not an electrical impulse crossing the gap.

The printed Synaptic vesicles leaders end on round membrane-bounded compartments in the upper terminal. Neurotransmitters points to green particles inside a vesicle and in the space below. These are the molecules contained by the vesicles and released into the junction. The source shapes and colours make the container and contents distinguishable but do not establish their real relative size.

Separate the source illustration from a scale measurement

The printed Synaptic cleft bracket spans the space between the upper terminal and lower membrane. Cleft is the source name for the synaptic gap. The longer label Ligand-gated channels with receptors for neurotransmitters points to a turquoise protein shape in the postsynaptic membrane. These receptor-bearing proteins provide the receiving binding sites needed in the syllabus account.

The image illustrates a common receptor-bearing channel model; it does not establish that every receptor in all synapses must be this channel type. It also does not identify these two cells as sensory, relay or motor neurones. Read the actual labels and connected regions rather than inventing those roles from shape alone. Try the identification before opening the separate key, and enlarge the unchanged image to follow the small leaders.

Pause and explain

Where does the receiving receptor-bearing channel leader end?

Put the idea to work

Worked example

Find vesicles, neurotransmitter, gap and receiving receptor proteins in the source image.

Show the worked solution
  1. Follow the vesicle and neurotransmitter leaders in the upper terminal.
  2. Read the cleft bracket and receptor-bearing channel leader on the lower membrane.

Answer Round upper compartments are vesicles; green particles are neurotransmitter; the cleft is the gap; the lower receptor-bearing channel proteins provide binding sites.

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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

Identify the printed source labels that establish the required synaptic structures.

Give me a hint

Match the source wording to the syllabus names.

Compare my reasoning
  1. Synaptic vesicles contain the green neurotransmitter molecules.
  2. Synaptic cleft is the gap; receptor-bearing channels are on the postsynaptic membrane.

Synaptic vesicles containing neurotransmitters; Synaptic cleft for the gap; Ligand-gated channels with receptors for neurotransmitters for the receiving receptor proteins.

Look for these in your work

  • Match all required features
  • Keep the original source labels
2 · Independent

Explain the difference between a round vesicle and a small green particle in the source view.

Give me a hint

Container and contained chemical are different.

Compare my reasoning
  1. The round membrane-bound structure is a vesicle.
  2. The green particle represents a neurotransmitter molecule.

The vesicle is a membrane-bounded container; the green particles represent neurotransmitter molecules stored inside or released from it.

Look for these in your work

  • Separate container and contents
  • Use the actual image key
3 · Transfer

Does the grey arrow from the whole-cell inset prove an electrical impulse jumps across the cleft?

Give me a hint

Read its purpose as enlargement of detail.

Compare my reasoning
  1. It connects the inset location with the magnified terminal view.
  2. Chemical transmission across the gap uses neurotransmitter molecules.

No. The grey arrow indicates magnification of a region; it is not evidence of an electrical impulse jumping across the cleft.

Look for these in your work

  • Read magnification correctly
  • Retain chemical gap transmission

Common mistakes

  • Treating the grey enlargement arrow as gap-crossing electrical travel.
  • Calling every synaptic receptor the same channel type.
Recall without your notes

What can you explain now?

Where does the receiving receptor-bearing channel leader end?

Compare with the explanation

On the postsynaptic membrane

That is the next cell’s receiving side.

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

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Make it stick

Locate the required structures in the published image and explain the magnification arrow.

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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