New
New
Year 11
Edexcel
Higher

Electron microscopy, and the size and scale of cells: including standard form

I can describe the size and scale of cells and cell structures, and explain how electron microscopy has increased our understanding of sub-cellular structures.

New
New
Year 11
Edexcel
Higher

Electron microscopy, and the size and scale of cells: including standard form

I can describe the size and scale of cells and cell structures, and explain how electron microscopy has increased our understanding of sub-cellular structures.

Share activities with pupils
Share function coming soon...

Lesson details

Key learning points

  1. Most cells are too small to be seen without a microscope.
  2. Comparison of the sizes of cells and cell structures in µm, nm, and in mm in standard form.
  3. Light microscopes have limited magnification and resolution.
  4. Electron microscopes have greater magnification and resolution, allowing much smaller structures to be seen clearly.
  5. 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.

It might be helpful to print out a large version of the unit conversion table to put up in the classroom so that pupils become more familiar with the unit prefixes.
Teacher tip

Equipment

calculators

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Video

Loading...

6 Questions

Q1.
What is the term for the most basic units of living organisms?
tissue
Correct answer: cell
organ
organism
Q2.
In which type of cell is genetic material typically not enclosed within a membrane-bound nucleus?
animal cell
plant cell
fungal cell
Correct answer: bacterial cell
Q3.
Which of the following is present in both prokaryotic and eukaryotic cells?
chloroplasts
Correct answer: cytoplasm
nucleus
mitochondria
Q4.
What is the main purpose of a microscope?
Correct answer: to magnify objects
to heat samples
to measure temperature
Q5.
Which of the following are eukaryotes?
Correct answer: plants
bacteria
Correct answer: animals
Correct answer: protists
viruses
Q6.
What is an electron?
Correct answer: 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.

6 Questions

Q1.
Which type of microscope uses electrons to view specimens in 3D?
light microscope
compound microscope
Correct answer: scanning electron microscope
transmission electron microscope
Q2.
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
Correct answer: the distance at which two distinct points of a specimen can still be seen
the size of the microscope stage
Q3.
Which microscope would be most suitable for observing detailed structures within a cell, such as chloroplasts?
light microscope
compound microscope
scanning electron microscope
Correct answer: transmission electron microscope
Q4.
A typical human hair has a diameter of approximately 60 micrometres (µm). What is its diameter in nanometres?
60 nm
600 nm
6000 nm
Correct answer: 60 000nm
Q5.
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
Correct answer: 2500x
250x
25x
Q6.
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
Correct answer: 2 × 10⁻⁸ m