Starter quiz
- What is the term for the most basic units of living organisms?
- tissue
- cell ✓
- organ
- organism
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- In which type of cell is genetic material typically not enclosed within a membrane-bound nucleus?
- animal cell
- plant cell
- fungal cell
- bacterial cell ✓
-
- Which of the following is present in both prokaryotic and eukaryotic cells?
- chloroplasts
- cytoplasm ✓
- nucleus
- mitochondria
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- What is the main purpose of a microscope?
- to magnify objects ✓
- to heat samples
- to measure temperature
-
- Which of the following are eukaryotes?
- plants ✓
- bacteria
- animals ✓
- protists ✓
- viruses
-
- What is an electron?
- Part of an atom that carries a negative charge and orbits the nucleus. ✓
- Part of an atom that carries a positive charge and found in the nucleus.
- Part of an atom that carries no overall charge and is found in the nucleus.
- Part of an atom where most of the mass of the atom is found.
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Exit quiz
- Which type of microscope uses electrons to view specimens in 3D?
- light microscope
- compound microscope
- scanning electron microscope ✓
- transmission electron microscope
-
- In microscopy, what does the term 'resolution' refer to?
- the brightness of the light source
- making small objects appear larger in order to see more detail
- the distance at which two distinct points of a specimen can still be seen ✓
- the size of the microscope stage
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- Which microscope would be most suitable for observing detailed structures within a cell, such as chloroplasts?
- light microscope
- compound microscope
- scanning electron microscope
- transmission electron microscope ✓
-
- A typical human hair has a diameter of approximately 60 micrometres (µm). What is its diameter in nanometres?
- 60 nm
- 600 nm
- 6000 nm
- 60 000nm ✓
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- A mitochondrion has a length of 2 micrometres (µm). In a microscopic image, the mitochondrion is represented as 0.5 centimetres. What is the magnification of the mitochondrion in the image?
- 25 000x
- 2500x ✓
- 250x
- 25x
-
- Given an image size of a red blood cell measuring 2 × 10⁻² mm and a magnification factor of 1000x, determine the real size of the red blood cell. Give your answer in metres (m) using standard form.
- 2 × 10⁵ m
- 2 × 10⁸ m
- 2 × 10⁻⁵ m
- 2 × 10⁻⁸ m ✓
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Worksheet
Presentation
Video
Lesson Details
Key learning points
- Most cells are too small to be seen without a microscope.
- Comparison of the sizes of cells and cell structures in µm, nm, and in mm in standard form.
- Light microscopes have limited magnification and resolution.
- Electron microscopes have greater magnification and resolution, allowing much smaller structures to be seen clearly.
- Electron microscopy has increased our understanding of sub-cellular structures.
Common misconception
Pupils might think that all cells are approximately the same size.
Calculations in the deck will allow pupils to compare the relative sizes of cells. It might be helpful to draw extra attention to this point.
Keywords
Light microscope - A type of microscope that uses visible light and lenses to generate magnified images of small objects.
Electron microscope - A type of microscope that uses a beam of electrons instead of light to magnify objects.
Magnification - Making small objects appear larger in order to see more detail.
Resolution - The minimum distance apart that two points of a specimen can be and still be clearly seen as separate from one another using a microscope.
Standard form - A way of writing down very large or very small numbers easily; e.g. 1000 = 10³.