You currently have JavaScript disabled on this browser/device. JavaScript must be enabled in order for this website to function properly.

ZingPath: Classification

Classification of Bacteria

Searching for


Learn in a way your textbook can't show you.
Explore the full path to learning Classification

Lesson Focus

Classification of Bacteria


Learning Made Easy

In this activity, you will be introduced to the applications of bacteria classification by differentiating bacteria based on the characteristics you observe throughout the Activity Object.

Over 1,200 Lessons: Get a Free Trial | Enroll Today

Now You Know

After completing this tutorial, you will be able to complete the following:

  • List the criteria of bacteria classification.
  • Differentiate bacteria according to their shapes.
  • Differentiate bacteria according to their Gram-staining properties.
  • Differentiate bacteria according to their oxygen needs.
  • Differentiate bacteria according to their nutrition.

Everything You'll Have Covered

A classification system is used to group all living things according to similarities into one of six kingdoms. Bacteria are microscopic living things that have their own kingdom.

Microbiology is the study of microscopic living things. Bacteria are organisms that are unicellular and cannot be seen without a microscope. A microscope is a scientific instrument used to enlarge objects that the eye can not normally see. The similarities and differences of bacteria can be observed using a microscope or through incubation. An incubator speeds up the growth of bacteria. Testing bacteria requires a microscope and an incubator and can be done in a laboratory.

Bacteria can be classified according to various criteria. Classification criteria might include: shape, oxygen needs, nutrition type and Gram staining. Bacterial shapes include: spherical shaped (coccus), rod shaped (bacillus), spiral shaped (sprillum), and comma shaped (vibrio). Aerobic bacteria need oxygen to survive, while anaerobic bacteria do not. Facultative bacteria can live with, or without, oxygen. Heterotrophic bacteria cannot make their own food and need to get their nutrients from another source. Autotrophic bacteria can synthesize their food from sunlight or from other inorganic compounds. The most basic method to classify bacteria is the use of Gram staining. Some bacteria stain either red or purple depending on the thickness of the peptidoglycan layer of the cell wall. Gram negative bacteria generally stain red while Gram positive bacteria generally stain purple.

When people get sick, doctors may prescribe antibiotics if the illness is caused by bacteria. Antibiotics come with an insert that explains the kinds of bacteria the medication is effective against.

Tutorial Details

Approximate Time 30 Minutes
Pre-requisite Concepts Students should be able to define the concept of classification, list kingdoms in classification, and explain the structure and function of bacteria.
Course Biology
Type of Tutorial Concept Development
Key Vocabulary aerobes, aerobic bacteria, anaerobes