Compare an electron microscope with a light microscope.

An electron microscope has much higher magnification and much higher resolving power.

Explain why an electron microscope can show structures a light microscope cannot.

Its higher resolving power lets two very close points be seen separately, so cells are shown in much finer detail.

How has the development of microscopes changed what biologists know about cells?

Better instruments have revealed more sub-cellular structures, so their functions could be worked out.

AQA GCSE Combined Science Biology 8464

Bioenergetics

Topic overview The photosynthesis reaction and the uses of glucose Rate of photosynthesis Why organisms respire, and aerobic versus anaerobic The equations for respiration, and fermentation Response to exercise Metabolism

Cell Biology

Topic overview Eukaryotes and prokaryotes Animal and plant cells Cell specialisation and differentiation Microscopy Chromosomes, mitosis and the cell cycle Stem cells in embryos, adults and meristems Therapeutic cloning, its risks, and cloning plants Diffusion and the factors affecting its rate Surface area to volume ratio and exchange surfaces Osmosis Active transport

Ecology

Topic overview Levels of organisation in an ecosystem, and what organisms need Competition, interdependence and stable communities Abiotic factors Biotic factors Adaptations Producers, food chains and sampling with quadrats and transects Predators, prey and measuring population size How materials are cycled Waste management and biodiversity Land use, deforestation and global warming Maintaining biodiversity

Homeostasis and Response

Topic overview Homeostasis The nervous system and the reflex arc Human endocrine system Insulin, glucagon and diabetes Hormones in human reproduction Contraception The use of hormones to treat infertility Negative feedback

Infection and Response

Topic overview Communicable (infectious) diseases Viral diseases Bacterial diseases Fungal and protist diseases Human defence systems Vaccination Antibiotics and painkillers Discovery and development of drugs

Inheritance, Variation and Evolution

Topic overview Sexual and asexual reproduction Meiosis DNA and the genome Genetic terms, dominant and recessive alleles Punnett squares, probability and genetic crosses Inherited disorders and sex determination Variation Evolution Selective breeding What genetic engineering is, and what it is used for GM crops, their risks, and the steps of the process Evidence for evolution, and extinction Fossils Resistant bacteria Classification of living organisms

Organisation

Topic overview Levels of organisation, and how enzymes work Amylase, proteases and lipases Bile, food tests and the effect of pH on amylase The heart, the lungs and double circulation The pacemaker, the blood vessels and the blood Coronary heart disease: a non-communicable disease Health issues Risk factors and causal mechanisms in disease Sampling, correlation and interpreting risk data Cancer Plant tissues, and transpiration and its rate Root hair cells, xylem, phloem and stomata

Cell Biology

Microscopy

3 things to know
Biology Paper 1

Overview

Magnification and resolution, how electron microscopes compare with light microscopes and what they revealed about sub-cellular structures, and calculating magnification, image size and real size, including conversion to micrometres and standard form.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

What is meant by the magnification of a microscope?

Key term

What is meant by the resolution of a microscope?

Key term

Which property limits how much detail can be seen, magnification or resolution?

Questions from this subtopic

Each one with the model answer underneath.

1
What is meant by the magnification of a microscope?
Model answer
How many times larger the image is than the real object.
2
What is meant by the resolution of a microscope?
Model answer
The smallest distance between two points that can still be seen as separate, which sets how much detail is visible.
3
Which property limits how much detail can be seen, magnification or resolution?
Model answer
Resolution, because magnifying further only makes a blurred image bigger.
4
Compare an electron microscope with a light microscope.
Model answer
An electron microscope has much higher magnification and much higher resolving power.
5
Explain why an electron microscope can show structures a light microscope cannot.
Model answer
Its higher resolving power lets two very close points be seen separately, so cells are shown in much finer detail.
6
How has the development of microscopes changed what biologists know about cells?
Model answer
Better instruments have revealed more sub-cellular structures, so their functions could be worked out.

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