Question

True or False a) An organism that can grow using oxygen as an electron acceptor and can also grow and metabolize in the absence of oxygen is called facultative. b) Yeasts are procaryotes. c) A bacteriophage is a virus that infects bacteria. d) When you supplement growth medium with amino acids, you should use the D-form.

Short answer

a) True; b) False; c) True; d) False.

Step-by-step solution

Determine the definition of a facultative organism

A facultative organism is defined as one that can grow in the presence of oxygen (aerobic conditions) as well as in the absence of oxygen (anaerobic conditions).

Verify if yeasts are prokaryotes

Yeasts are not prokaryotes; they are eukaryotic microorganisms as they have a defined nucleus and other organelles.

Define a bacteriophage

A bacteriophage is a type of virus that specifically infects and replicates within bacteria.

Determine the form of amino acids used in growth mediums

In biological systems, the L-form of amino acids is most commonly used for protein synthesis and metabolism rather than the D-form.

Key concepts

Facultative Organisms

Facultative organisms have remarkable versatility. They can survive and grow in both aerobic (with oxygen) and anaerobic (without oxygen) environments.
This dual capability allows them to thrive in diverse conditions. For instance, facultative anaerobes can use oxygen for aerobic respiration when it's available, which is more efficient.
When oxygen is scarce, they can switch to anaerobic processes like fermentation to generate energy.

• Typical facultative organisms include certain bacteria and yeasts.
• They adapt their metabolism depending on the environment.

This adaptability is key to their survival in fluctuating environments.

Yeasts are Eukaryotes

Yeasts belong to the eukaryotic kingdom. This means they have a well-defined nucleus and complex organelles, unlike prokaryotes like bacteria.
Eukaryotic cells, including yeasts, have internal structures like mitochondria, the endoplasmic reticulum, and Golgi apparatus, which play vital roles in cellular processes.

• Yeasts can be unicellular or form colonies.
• They are crucial in baking, brewing, and scientific research.

Understanding that yeasts are eukaryotes helps differentiate them from simpler organisms.

Bacteriophage Definition

A bacteriophage, or phage, is a virus that infects bacteria. These viruses are highly specific to their bacterial hosts.
When a phage attaches to a bacterium, it injects its genetic material into the host cell, hijacking the bacterium's machinery to produce more phages.

• Bacteriophages play a crucial role in controlling bacterial populations.
• They are used in research and biotechnology for genetic tools and therapies.

Phages are a fascinating example of the complexity and specificity of viral life.

L-form Amino Acids

Amino acids come in two mirror-image forms: L-form and D-form. For biological organisms, the L-form is the predominant type used for protein synthesis and metabolic processes.
Cells have evolved to specifically recognize and utilize L-form amino acids.
Supplementing growth media with L-form amino acids ensures proper protein synthesis and cellular function.

• L-form amino acids are the building blocks of proteins in all living organisms.
• D-form amino acids are rare and usually associated with bacterial cell walls.

This distinction is crucial for effective biological research and applications.