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Microscopy, cell fractionation and measurement · A Level Biology · Courselo

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Biology
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Cells and cell division

Microscopy, cell fractionation and measurement

Cells and cell division · Lesson 2 of 4

Lesson 2 of 4

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Unit 2

Cells and cell division

4 lessons · 7 h of study

Cell ultrastructure including prokaryotes, eukaryotes and viruses1 h 45 min of study
Microscopy, cell fractionation and measurementReading · 0%
Plasma membranes and cell transport1 h 45 min of study
Cell cycle, mitosis, meiosis and stem cells2 h of study

This unit is ≈8% of the Biology, across 4 lessons. Full syllabus

Lesson 2 of 4 · Cells and cell division

Microscopy, cell fractionation and measurement

3 quick checks≈2% of the testCore: Core: tested on most papers

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By the end you’ll be able to

compare light microscopes, transmission electron microscopes and scanning electron microscopes in terms of magnification, resolution, specimen preparation, image detail and limitations
explain how staining, sectioning and electron beams improve visibility and resolution, and recognise that electron microscopy requires dead specimens in a vacuum

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Adaptive questions on microscopy, cell fractionation and measurement.

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calculate actual size, image size and magnification using $\text{magnification}=\dfrac{\text{image size}}{\text{actual size}}$, converting between units such as mm, $\mu\text{m}$ and nm

measure cells and organelles from micrographs using scale bars and eyepiece graticules where specified, and interpret the significance of resolution when comparing images

describe the process of cell fractionation, including homogenisation, filtration and differential centrifugation, and explain how organelles are separated by size and density

apply knowledge of centrifugation conditions, isotonic media, buffering and low temperature to explain how cell components are isolated without damage

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PreviousCell ultrastructure including prokaryotes, eukaryotes and viruses Next lessonPlasma membranes and cell transport