Microbiology

What Microbiology covers

Microbiology is examined in Unit A2 6, Microbiology — internally assessed, one of five Double Award optional units (two are taken). It covers bacteria, fungi and protozoa, viruses, viroids and prions, classifying bacteria, fungi and viruses, light and electron microscopy, laboratory safety, biocontainment and quality assurance, aseptic technique, growth media and inoculation, counting and measuring microbial growth, growth requirements and growth inhibition, antibiotics, PCR, gene therapy and pharmaceutical microbiology and the gut microbiome in health and disease.

The 10 subtopics

Each one has its own page.

• Bacteria, fungi and protozoaThe structure and reproduction of bacteria, endospores, fungi, hyphae and yeasts, protozoa and the diseases they cause, and bacterial and fungal cells compared.Open →
• Viruses, viroids and prionsVirus structure and replication, lysis and budding, bacteriophages, why antibiotics do not work on viruses, viroids, prions and prion diseases.Open →
• Classifying bacteria, fungi and virusesBergey's Manual, Gram staining and why it works, cocci, bacilli and spirilla, oxygen requirements, the four fungal groups, and classifying viruses by size, nucleic acid, capsid, host and disease.Open →
• Light and electron microscopyMagnification and resolution with worked calculations, oil immersion and phase contrast, transmission and scanning electron microscopes, sample preparation, and setting up a light microscope.Open →
• Laboratory safety, biocontainment and quality assuranceHazard groups and the Control of Substances Hazardous to Health Regulations, positive and negative pressure containment, laminar flow and safety cabinets, HEPA filters, autoclaving, quality assurance and controls, lab books and practical reports.Open →
• Aseptic technique, growth media and inoculationAseptic technique and flaming loops, disinfection and sterilisation, preparing media and filter sterilisation, streak, pour and lawn plates, mycelial discs, plaque assays and safe incubation.Open →
• Counting and measuring microbial growthSerial dilutions, viable and total counts with worked examples, colony-forming units, haemocytometers, turbidity, fungal growth rates, dry mass, plaque counts and microbiological assays.Open →
• Growth requirements and growth inhibitionNutrients, oxygen, temperature, light, pH and surfaces, inhibition by osmotic potential, irradiation, antibiotics, antifungals and antivirals, zones of inhibition and comparing growth monitoring methods.Open →
• Antibiotics, PCR, gene therapy and pharmaceutical microbiologyMicrobes in the body, the discovery and production of penicillin, antibiotic resistance and MRSA, viral vectors in gene therapy, PCR diagnosis, infection spread, pharmaceutical microbiology and phage therapy.Open →
• The gut microbiome in health and diseaseThe functions of a healthy gut microbiome, dysbiosis and antibiotics, high-throughput and 16S sequencing, culture and metabolomics, inflammatory bowel disease, obesity and bowel cancer, and faecal microbiota transplants.Open →

What you need to know

Answer each one before you reveal it.

Take Microbiology further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Gram-positive vs Gram-negative

  Gram-positive: bacteria with a thick peptidoglycan wall that stay purple after the stain. Gram-negative: bacteria with a thin wall and outer membrane that turn pink after the stain.

• Viroid vs Prion

  Viroid: a short naked circle of RNA that infects plants. Prion: an infectious misfolded protein with no genetic material.

• Disinfection vs Sterilisation

  Disinfection: reducing the number of microbes on a surface to a safe level. Sterilisation: killing or removing every microbe, including spores.

Questions from this topic

Each one with the model answer underneath.

1. 1

   What are the characteristic features of a bacterial cell?

   Model answer

   A bacterium is a prokaryote with no nucleus, a single circular chromosome and often small rings of DNA called plasmids. The cell has 70S ribosomes and a cell wall made of peptidoglycan.

2. 2

   What structures may be found on the outside of a bacterial cell?

   Model answer

   Some bacteria have a slimy capsule that protects them and helps them stick to surfaces. Flagella allow movement, and pili help bacteria attach to cells and exchange DNA.

3. 3

   How do bacteria reproduce?

   Model answer

   Bacteria reproduce asexually by binary fission. The chromosome is copied and the cell divides into two identical daughter cells.

4. 4

   What are bacterial endospores?

   Model answer

   Endospores are tough, dormant structures formed by some bacteria, such as Clostridium and Bacillus, in harsh conditions. Endospores survive boiling, drying and many disinfectants.

5. 5

   Give two functions of bacteria that benefit humans.

   Model answer

   Gut bacteria help digest fibre and make vitamin K. Bacteria are also used to make foods such as yoghurt and medicines such as insulin.

6. 6

   What are the characteristic features of fungi?

   Model answer

   Fungi are eukaryotes with a nucleus and cell walls made of chitin. Fungi feed by secreting enzymes onto their food and absorbing the products.

What is inside Levo

Six ways to work the same material.

Microbiology revision questions

What does Microbiology cover in CCEA A-Level Life and Health Sciences?

10 subtopics: bacteria, fungi and protozoa, viruses, viroids and prions, classifying bacteria, fungi and viruses, light and electron microscopy, laboratory safety, biocontainment and quality assurance, aseptic technique, growth media and inoculation, counting and measuring microbial growth, growth requirements and growth inhibition, antibiotics, pcr, gene therapy and pharmaceutical microbiology and the gut microbiome in health and disease. Each one has its own page with questions and model answers.

How is Microbiology organised?

By the CCEA 0008 specification, subtopic by subtopic, so it matches the order you are taught it in.