Bacteria

Classifying Prokaryotes

Many archaebacteria live in extreme environments.

Methanogens live in oxygen-free environments, such as thick mud and animal digestive tracts.

Halophiles live in salty environments and thermophiles in hot springs where water temperatures approach the boiling point.

Importance of Bacteria

FUNGI

is any member of the group of eukaryotic organisms that includes unicellular microorganisms such as yeasts and molds, as well as multicellular fungi that produce familiar fruiting forms known as mushrooms

Identifying Prokaryotes

Prokaryotes are identified by characteristics such as:

• shape
• the chemical structure of their cell walls
• the way they move
• the way they obtain energy

PROTOZOA

• Protozoa are a diverse group of unicellular eukaryotic organisms
• They come in many different shapes and sizes ranging from an Amoeba which can change its shape to Paramecium with its fixed shape and complex structure. They live in a wide variety of moist habitats including fresh water, marine environments and the soil.

Identifying Prokaryotes

Spherical prokaryotes are called cocci (coccus, singular).

4. Pest control

Cocci

Identifying Prokaryotes

Rod-shaped prokaryotes are called bacilli (bacillus, singular).

Bacilli

3. Vitamin synthesis

2. Fibre retting

Identifying Prokaryotes

Spiral and corkscrew-shaped prokaryotes are called spirilla (spirillum, singular).

Spirilla

Bacteria

1. Biotechnology-is defined as the use of microorganisms such as bacteria, fungi and algae for the manufacturing and services industries

- Fermentation processes, such as brewing, baking, cheese and butter manufacturing, Bacteria, often Lactobacillus in combination with yeasts and fungi, have been used for thousands of years in the preparation of fermented foods such as cheese, pickles, vinegar, wine, and yogurt.

- Chemical manufacturing such as ethanol, acetone, organic acid, enzymes, perfumes etc. In the chemical industry, bacteria are most important in the production pharmaceuticals

Identifying Prokaryotes

Metabolic Diversity

Cell Walls

Two different types of cell walls are found in eubacteria. A method called gram staining tells them apart.

Gram-positive bacteria have thick cell walls with large amounts of peptidoglycan.

Gram-negative bacteria have thinner cell walls inside an outer lipid layer.

Prokaryotes are divided into two main groups:

• Heterotrophs get their energy by consuming organic molecules made by other organisms.

• Autotrophs make their own food from inorganic molecules.

Growth and Reproduction

Binary fission is a type of asexual reproduction in which an organism replicates its DNA and divides in half, producing two identical daughter cells.

Growth and Reproduction

Conjugation occurs when a hollow bridge forms between two bacterial cells, and genes move from one cell to the other.

What is gained by

exchanging DNA?

Growth and Reproduction

Spore Formation 

In unfavorable growth conditions, many bacteria form spores.

An endospore forms when a bacterium produces a thick internal wall that encloses its DNA and some of its cytoplasm.

Not for children under 1 year old.

Importance of Bacteria

Bacteria are vital to the living world.

Some are producers that capture energy by photosynthesis.

Others are decomposers that break down the nutrients in dead matter.

Bacteria are also crucial players in the nitrogen cycle as they capture nitrogen from the atmosphere in nitrogen fixation.

Bacteria that must live without oxygen are called

obligate aerobes.

facultative anaerobes.

obligate anaerobes.

facultative aerobes.

Rod-shaped prokaryotes are called

bacilli.

cocci.

spirilla.

streptococci.

Prokaryotes that make their own food molecules from carbon dioxide and water but live where there is no light are called

photoautotrophs.

photoheterotrophs.

chemoautotrophs.

chemoheterotrophs.

Bacteria that attack and digest the tissue of dead organisms are called

decomposers.

nitrogen fixers.

chemoautotrophs.

archaebacteria.

Which characteristic distinguishes eubacteria from archaebacteria?

Eubacteria lack peptidoglycan in their cell walls.

Eubacteria contain peptidoglycan in their cell walls.

Eubacteria lack a nucleus.

Eubacteria do not possess mitochondria.

Importance of Bacteria

Human Uses of Bacteria

We depend on bacteria for many things, including:

• foods and beverages
• removal of waste and poisons from water
• mining minerals from the ground
• synthesis of drugs and chemicals via genetic engineering
• production of vitamins in human intestines

Can you think of other uses?