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GLOSSARY
DNA: Deoxyribonucleic Acid; Sequence of Nucleic acids which hold information for assembly of proteins.
RNA: Ribonucleic Acid; Sequence of nucleic acids which are used to produce proteins.
Polymerase: Enzyme which binds free nucleotides to a growing strand, either RNA or DNA.
Amino acid: subunit of a polypeptide chain; primary unit of proteins.
Ribosomes: Structure where amino acids are strung together to form proteins.
Plasmid: Extra DNA that carries a few extra genes and replicates independently of the host.
Transcription: Process at which a polymerase takes DNA and creates messenger RNA.
F+: Fertility factor; Plasmids with this ability have the ability to conjugate.
Sex Pilus: Tube which connects two bacteria during conjugation.
Conjugation is the process at which genetic information is passed among
microorganisms. It serves as an important adaptation in bacteria
as they gain resistance against antibiotics. The following
information will provide a summary of the mechanisms of
conjugation and how bacteria gain antibiotic
resistance from it.
Part I
The key to all life is the DNA template. It is composed of substances called nucleic acids which include Adenosine, Guanine, Cytosine, and Thymine. The function of the template is to provide the instructions to produce different proteins.Proteins are then used to perform the everyday functions of life, including; providing substances for cell structures & providing a substrate to speed up ordinarily slow reactions (catalyst).
The production of protein products from DNA templates requires an intermediate step where another Nucleic acid called RNA is produced. RNA is then used to create proteins. It is necessary for the production of RNA to utilize a polymerase. A polymerase reads the DNA template and takes corresponding RNA nucleotide bases and inserts them to make the RNA strand. Since the polymerase is generally non-specific, it will read any DNA template. This means that other DNA templates other then the hosts' can be converted into the RNA strand.
Proteins are then made from the RNA strand through structures called Ribosomes. Essentially, the RNA strand (called a Messenger RNA) is inserted into a ribosome. Every three RNA nucleotide base corresponds to one specific Amino Acid which is the building block of a protein. As the RNA strand is run through the ribosome, corresponding Amino acids are brought in by Transfer RNAs, and fused together in the ribosome by Peptide bonds.
An important element of conjugation is a structure composed of DNA called
a plasmid. Essentially, the plasmid can hold additional information, which
codes for proteins that can sometimes be utilized by the host. Since polymerases
work non-specifically, information can be transcribed from them
and utilized by any host.
DNA on plasmids can code for any protein. Among the many things plasmids
can code for is for the ability of conjugation.Most plasmids that
have this ability are considered F+ positive and are
said to have the F factor. (F = Fertility). This codes for the Sex Pilus
necessary for conjugation. It is very important that a plasmid have or
associate with another plasmid with this ability in order for the plasmid
to propagate.
Plasmids can also possess information for any protein sequence. This
means the plasmid can hold information necessary to deactivate an antibiotic
and give its host antibiotic resistance. It may also be beneficial as gene
sequences can be placed onto the plasmid and mass produced. For example
Insulin can be placed on a plasmid and transferred to E. coli bacteria
and mass produced.
Conjugation is the process at which genetic information
is passed from one organism to another. Conjugation among bacteria involve
the passing of a plasmid from a host bacteria to a recipient bacteria.
The first step of conjugation is the plasmid
will replicate itself so that the host has two copies. The plasmid then
codes for proteins to form the sex pili.
The host bacteria then waits until a neighboring
bacteria contacts it, at which point the pili will pass through the cell
wall of the recipient bacteria. The replicated plasmid then goes from circular
shape to linear so that it can transfer through the plasmid and enter the
recipient cell. Conjugation is then complete.