Question

Bacteria can synthesize unsaturated fatty acids only under anaerobic conditions.

Answer 1

Bacteria synthesize unsaturated fatty acids under anaerobic conditions through mechanisms like anaerobic respiration or fermentation. Strict anaerobes require environments completely devoid of oxygen, while facultative anaerobes adjust to oxygen availability. Obligate anaerobes are cultivated using specialized equipment to ensure an anaerobic environment.

Step-by-step explanation:

Synthesis of unsaturated fatty acids by bacteria occurs in different ways depending on the available environmental conditions, particularly the presence or absence of oxygen. Strict anaerobes, which are bacteria that live only in environments devoid of oxygen, are capable of synthesizing unsaturated fatty acids under anaerobic conditions using pathways such as anaerobic respiration or fermentation. Exposure to oxygen can be lethal to these bacteria due to a lack of defenses against oxidative stress, highlighting the importance of a strictly anaerobic environment.

• Strict anaerobes like the Clostridia bacteria and some Archaea can only synthesize fatty acids without oxygen.
• Facultative anaerobes can alternate between using oxygen for aerobic respiration and resorting to fermentation when oxygen is not available.
• Some prokaryotes use alternative electron acceptors, such as nitrates or sulfate, instead of oxygen, forming products like hydrogen sulfide or methane.

The study of these organisms often requires specialized equipment to maintain anaerobic conditions, such as an anaerobic jar, to successfully grow obligate anaerobes in the laboratory setting. However, it's important to note that a significant portion of bacteria and archaea are unculturable due to their intricate and not yet fully understood growth requirements.

Answer 2

The question focuses on the capability of certain anaerobic bacteria to synthesize unsaturated fatty acids only under anaerobic conditions. These organisms, including strict and facultative anaerobes, rely on anaerobic respiration and require culture methods devoid of oxygen. Anaerobic respiration involves alternative electron acceptors and specific cultivation challenges make many prokaryotes unculturable in lab environments.

Step-by-step explanation:

The question pertains to the ability of bacteria to synthesize unsaturated fatty acids under specific conditions. In the absence of oxygen, certain anaerobic bacteria, such as strict anaerobes and obligate anaerobes, can carry out life processes. Strict anaerobes thrive in oxygen-free environments and are susceptible to oxygen due to their lack of cellular defenses against oxidative stress.

On the other hand, facultatively anaerobic bacteria can alternate between aerobic respiration and fermentation, depending on oxygen availability. Some prokaryotes, including certain bacteria and Archaea, specifically utilize anaerobic respiration where alternative electron acceptors, like nitrates for some soil bacteria or sulfur compounds for sulfate-reducing bacteria and Archaea, are used instead of oxygen.

It is essential to culture anaerobic bacteria in an oxygen-free environment, often using specialized equipment like an anaerobic jar. This type of respiration involves the reduction of substances other than oxygen, which allows the regeneration of NAD+ from NADH, crucial to maintaining the energy production within the cell.

Furthermore, the domains Bacteria and Archaea show differences in their cellular structures, for example, their cell membranes often differ in the use of fatty acids versus phytanal groups. Culturing these organisms can be challenging due to their specific requirements, which are not always understood or achievable in a laboratory setting. This complexity contributes to why over 99 percent of bacteria and archaea are unculturable.