IB biology B4.2.2 Differences between Organisms that are Obligate Anaerobes, Facultative Anaerobes and Obligate Aerobes; B4.2.7 Diversity of Nutrition in Archaea

Obligate aerobes

Obligate aerobes

require continuous oxygen supply, so only live in oxic (with oxygen) environments.

Obligate anaerobes

inhibited or killed by oxygen, so only live in anoxic (without oxygen) environments.

Facultative anaerobes

use oxygen if available, so can live in either oxic or anoxic environments.

obligate aerobes, obligate anaerobes, and facultative anaerobes.

Flashcard: Types of Oxygen Requirements in Microorganisms

*Term:* __________ are organisms that use oxygen to metabolise substances, like sugars or fats, to produce ATP through aerobic cellular respiration. In this type of respiration, oxygen serves as the final electron acceptor in the electron transport chain.

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*Term:* __________ are organisms that produce ATP via anaerobic cellular respiration or fermentation.  These organisms are killed by atmospheric levels of oxygen. 

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*Term:* __________ are able to grow in both the oxic and anoxic environments.  Facultative anaerobes produce ATP via aerobic cellular respiration, anaerobic respiration and/or fermentation.  

2 types of obligate anaerobes

Flashcard: Types of Obligate Anaerobes

Definition: ________ uses an electron acceptor other than oxygen in the electron transport chain. Examples of alternative electron acceptors include sulfate, nitrate and iron. doesn’t use an electron transport chain. Humans undergo _________ and other organisms can undergo _________. 

(Answer: anaerobic respiration, lactic acid fermentation, alcoholic fermentation)

Archeas unique characteristics:

• Their cell membrane has branched fatty acids ① with unique bonding of the fatty acid to the glycerol ②.

• Their cell walls are made of a different molecule than those of bacteria.

• Their genomes are larger and more complex than those of bacteria.

• Many are  extremophiles, preferring extreme hot or cold, extreme salinity, or other conditions that are hostile to most other forms of life on earth. 

Nearly all archaea are ______

Autotrophs

The term for obtaining energy from light:

Phototrophs

The term for obtaining energy from chemicals:

Chemotrophs

Photoautorophs

organisms that can utilize light energy from sunlight and elements from inorganic compounds like CO2 to produce organic materials needed to sustain their own metabolism

Photoheterotrophs

they are organisms that use light for energy, but cannot use carbon dioxide as their sole carbon source

Chemoautotrophs

organism that takes inorganic chemicals and transforms it into energy

Chemoheterotrophs

microbes that use organic chemical substances as sources of energy and organic compounds as the main source of carbon

Photoautotrophic archaea does nonclassical photosynthesis. List the characteristics of photoautotrophic archaea:

• pigments other than chlorophyll are used

• photosynthesis does not generate oxygen

• rather than an electron transport chain, light-activated ion pumps generate ion gradients (C1.3.12)

Living environment of chemoautotrophic archea:

deep-sea vents, the deep soil and acidic environments

Methanogenesis

A type of chemoautotrophic nutrition that archaea are known to perform

Methanogenic archaea are all a type of obligate ________.

Anaerobes (performing anaerobic cellular respiration)