Tag: zoology

In Streptococcus pneumoniae, the virulent strain possesses a polysaccharide capsule that makes the colonies appear smooth (S-strain), while the non-virulent strain lacks a capsule and appears rough (R-strain).

Frederick Griffith first demonstrated bacterial transformation in 1928 using Streptococcus pneumoniae.

The genetic code is a set of rules by which information encoded in genetic material is translated into proteins by living cells, specifically determining the sequence of amino acids.

The genetic code is a triplet code, meaning a sequence of three nucleotides (a codon) specifies a single amino acid.

The operon model for gene regulation in prokaryotes was proposed by François Jacob and Jacques Monod in 1961.

RNA polymerase binds to the promoter region of an operon to initiate the transcription of the structural genes.

The central dogma of molecular biology describes the flow of genetic information: DNA is transcribed into mRNA, which is then translated into a polypeptide chain using tRNA and amino acids.

Frederick Griffith conducted the first transformation experiments in 1928, providing the foundation for identifying DNA as the genetic material.

In the Hershey-Chase experiment, the bacteriophage injects its DNA into the bacterium while the protein coat remains outside. Since the bacterium becomes radioactive, it confirms that the DNA, which carries the radioactive label, was successfully transferred into the host.

Frederick Griffith's experiment with Streptococcus pneumoniae demonstrated that a 'transforming principle' could change non-virulent bacteria into virulent ones, which was later identified as DNA.