Describe - bacterial gene

Describe: bacterial gene b.stev

Transcriptional Promoter

Initiation Codon

Operator

Operons

Open Reading Frame

Ribosome Binding Site

Start/ Stop Codon

Transcription Terminator

BACTERIAL GENE components to be outlined in the description:

- easily utilise glucose as a nutrient

- an example of when transcription is used

IF: lactose is present & there is insufficient glucose for required

needs the bacteria must produce specific enzymes so that the

sugar lactose can be utilised in a metabolic pathway : enzymes

B galactosidase

Permease

Galactose acetylase

the presence of lactose causes the repressor protein NOT to

bind to the transcription unit - signalling the process to begin

ABOUT BACTERIA: (Campbell N. A, Reece J. B, 2004)

Open Reading Frame : sequence whereby NO stop codons are present thus, the sequence represents a particular function. The sequence(s) vary in length in accord to their particular function they perform. THE particular codon sequence that initiates the point upon the transcription factor where the process begins is the amino acid: Methionine – AUG (start codon) this is an example of one of the 64 different amino acids that surmount to the, ”dictionary of the genetic code.” AND, when the required sequence is read there are: 3 codons that initiate the process to cease UAA/ UAG/ UGA – known only as stop codon(s)

when the REPRESSOR PROTEIN binds to the OPERATOR it prevents transcription regulatory gene operator structural genes promoter TRANSCRIPTION FACTOR OPERON RNA polymerase direction of transcription

regulatory gene operator structural genes promoter a RIBBON of codons is made - named: the mRNA transcript - when completed it detaches RNA polymerase direction of transcription

TO commence transcription : a promoter attracts RNA polymerase to bind specifically in place to it PROMOTER: sequence in DNA - RNA polymerase recognises then binds in position to the start point; extends several dozen nucleotide pairs upstream ALSO: promoter determines which of the 2 strands of DNA helix is going to be used as the template strand in transcription (Campbell N. A, Reece J. B, 2004)

OPERONS: structural genes clusters of genetic codes that provide the: codons for proteins to be made for metabolic function to nutrients OPERATOR: before operon sequence of codons: codons that consist of the operator are placed to determine if TRANSCRIPTION is to take place repessor protein can attach to this point to prevent the transcription

TRANSCRIPTION TERMINATOR: a stop codon is read in the sequence that causes the m RNA transcript to release and RNA polymerase detaches from the DNA transcript THE made m RNA transcript floats within the cytoplasm of the bacterium until it encounters a ribosome RIBOSOME: makes the useable proteins for the bacteria consists: two parts WHEN complete it pauses, breaks off the protein & moves to the next start codon to create the next protein needed Large: consists of 49 proteins Small: consists of 33 proteins (Pommerville J.C, 2004)

A P E large ribosome mRNA transcript small ribosome bind site: upstream to the start codon is a specific sequence that the small ribosome recognises and binds to, so follows the large ribosome that attaches above this 5’ 3’ RIBOSOME bind sites E: exit site P: peptidyl-tRNA site A: aminoacyl-tRNA site direction of translation

Bibliography Campbell N. A, Reece J. B. (2005). Biology (7th ed.) . San Francisco: Benjamin Cummings Pommerville J.C. (2004). Alcamo’s – Fundamentals of Microbiology (7 th ed.). Massachusetts: Jones and Bartlett.