You could identify an unknown bacterium by all of the following except
a. hybridizing a DNA probe from a known bacterium with the unknown’s DNA.
b. making a fatty acid profile of the unknown.
c. specific antiserum agglutinating the unknown.
d. ribosomal RNA sequencing.
e. percentage of guanine + cytosine.

Verified step by step guidance

1. Understand the context: The question is about methods used to identify unknown bacteria. Each option represents a different technique.
2. Option a: DNA hybridization involves using a DNA probe from a known bacterium to see if it binds to the unknown bacterium's DNA, indicating similarity.
3. Option b: Fatty acid profiling involves analyzing the types and quantities of fatty acids in the bacterium's cell membrane, which can be characteristic of certain species.
4. Option c: Agglutination with specific antiserum involves using antibodies that bind to specific antigens on the bacterium's surface, causing clumping if the bacterium is recognized.
5. Option d: Ribosomal RNA sequencing involves analyzing the sequence of ribosomal RNA, which is highly conserved and useful for identifying bacteria. Option e: The percentage of guanine + cytosine (G+C content) in DNA can give some information about the bacterium, but it is not specific enough for identification.

Key Concepts

DNA Hybridization

DNA hybridization is a molecular technique used to identify the presence of specific DNA sequences. By using a labeled DNA probe from a known bacterium, researchers can determine if the unknown bacterium shares genetic material with the known one. This method is highly specific and can provide insights into the genetic relationships between different bacterial species.

Fatty Acid Profiling

Fatty acid profiling involves analyzing the types and quantities of fatty acids present in a bacterium's membrane. This technique can help differentiate bacterial species based on their unique fatty acid compositions. It is particularly useful for identifying Gram-negative bacteria, as their fatty acid profiles can vary significantly among species.

Ribosomal RNA Sequencing

Ribosomal RNA (rRNA) sequencing is a method used to identify and classify bacteria based on the sequences of their ribosomal RNA genes. Since rRNA is highly conserved across different species, variations in these sequences can provide valuable phylogenetic information. This technique is widely used in microbial taxonomy and can help in understanding evolutionary relationships among bacteria.