Unit 3: Biodiversity - Eubacteria and Archaea

What are the 2 major groups of prokaryotes?

Bacteria and Archaea

What are the general characteristics of bacteria?

Single-celled, prokaryotic organisms. They are the smallest and simplest organisms on Earth, have no membrane-bound organelles and reproduce asexually via binary fission.

Extremophiles

Organisms, especially archaebacteria, that thrive in extreme enviornments, such as high heat, salinity or acidity

Conjugation in bacteria?

A form of sexual reproduction where two bacterial cells exchange genetic material, increasing diversity

Plasmids

small circular DNA molecules found in bacteria that are seperate from the main chromosome

3 shapes of bacteria?

• Cocci: spherical

• Bacilli: Rod-shaped

• Spirilla: Spiral

What are the key structural components of bacteria?

Bacteria have a cell wall, cell membrane, cytoplasm containing ribosomes and DNA (single chromosome) and may contain a plasmid or flagella/pili for movement

How do bacteria obtain their energy?

Autotrophy (making their own food) or Heterotrophy (absorbign organic compounds), using primary energy sources like sunlight or chemical energy)

Types of bacterial respiration

• Obligate aerobes: Require oxygen

• Facultative anaerobes: Can perform both aerobic and anaerobic respiration

• Obligate anaerobes: Cannot survive in the presence of oxygen

How do bacteria reproduce?

Asexually by binary fission, where the parent cell divides into two identical offspring without genetic material exchange

Conjugation in bacteria

Conjugation is a process where two bacterial cells connect via a protein bridge, transferring plasmid DNA increase genetic diversity. It is considered a form of sexual reproduction

What is the difference between archaebacteria and eubacteria?

Archaeacteria live in extreme environements, have different cell wall and membrane structures and more than half of their genes differ from eubacteria. Eubacteria are the most common prokaryotes and are involved in nitrogen fixation and decomposition

What are halophiles?

Halophiles are extremophiles that thrive in high salt concentrations, such as in salt lakes.

What are some helpful uses of bacteria?

Bacteria are used in waste management, sewage treatment, dairy food production, nitrogen fixation, decomposition, digestion and pest control

How do bacteria cause disease?

By damaging cells/tissues or releasing toxins that interfere with normal host functions

What are vaccines and antibiotics used for in relation to bacterial diseases?

Vaccines stimulate the immune system to proevent bacterial diesases while antibiotics are compounds that inhibt bacterial growth

Chemoautotroph

Mode of nutrition for bacteria using inorganic chemicals as the energy source and CO2 as the carbon source

Chemoheterotroph

Mode of nutrition for bacteria using organic compounds as the energy source and as the carbon source

Photoautotroph

Mode of nutrition for bacteria using light as the energy source and CO2 as the carbon source

Photoheterotroph

Mode of nutrition for bacteria using light as the energy source and organic compounds as the carbon source