Identify red and white blood cells in diagrams
Use nucleus, cell outline and central pallor in a schematic comparison.
Section B9.4 · Blood
Cross-referenced to the 2028–2029 0653 section using original teaching from the related single-science courses. A 0653-specific objective-by-objective and Core/Supplement review is in progress. Written practice is self-checked and does not demonstrate supervised laboratory competence or award an official Cambridge grade.
Before you begin
- Recall the four blood components.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What is a nucleus?
What you will learn
- Recognise the mature red-cell pattern
- White cells retain a nucleus
Recognise the mature red-cell pattern
The original diagram labels A as a mature human red blood cell. It is drawn as a biconcave disc viewed from above: the centre is paler than the rim, and there is no nucleus. The pale centre represents the thinner central region, not an open hole through the cell.
Mature human red cells lack a nucleus, but not all animals have that pattern and developing cells differ. Use the stated human specimen. A drawing is simplified and not to scale; its size on the screen does not provide an actual diameter.
White cells retain a nucleus
B and C are white blood cells. B has a large round nucleus; C has a lobed nucleus with surrounding cytoplasm. Their shared nucleated pattern distinguishes them from mature human red cells. White cells have different shapes and functions, so do not insist that every white-cell nucleus looks the same.
Colour is a teaching convention in this diagram. Identify A using its disc-like outline and lack of nucleus, and B/C using their nuclei. The detailed lymphocyte/phagocyte names are explored in the Extended sequence. Core identification here asks for red or white cells using observable features rather than disease diagnosis.
Sources for this lesson
Pause and explain
Which diagram feature supports white-cell identification?
Worked example
Identify A and B/C as red or white cells and give evidence independent of colour.
Show the worked solution
- A has no nucleus and a paler disc centre.
- B and C contain nuclei.
Answer A mature human red cell; B and C white cells. The presence or absence of a nucleus supports the distinction.
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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.
Identify A and state two visible features supporting the answer.
Give me a hint
Use shape and nucleus evidence.
Compare my reasoning
- A is disc-like with a paler central region.
- It has no nucleus.
A mature human red blood cell: disc-like central pallor and no nucleus.
Look for these in your work
- Name the cell
- Use two structural features
Identify B and C at the Core red/white-cell level.
Give me a hint
Their nucleus shapes differ but both have one.
Compare my reasoning
- B has a round nucleus.
- C has a lobed nucleus.
B and C are white blood cells; both contain a nucleus.
Look for these in your work
- Identify both
- Use nucleus evidence
The diagram is printed in grayscale. How can A still be distinguished from B and C?
Give me a hint
Focus on structures rather than colour.
Compare my reasoning
- A lacks a nucleus and has a pale disc centre.
- B/C show nuclei and surrounding cytoplasm.
Use A’s lack of nucleus and disc structure versus the nuclei in B/C; colour is unnecessary.
Look for these in your work
- Compare structures
- Retain evidence without colour
Common mistakes
- Calling central pallor a nucleus.
- Treating all white-cell nuclei as identical.
What can you explain now?
Which diagram feature supports white-cell identification?
Compare with the explanation
A nucleus within the cell
B and C have nuclei.
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Make it stick
Identify the red and white cells with their colours covered.
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.