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21 Cards in this Set

  • Front
  • Back
are viruses that infect bacteria
Bacteriophage (or phage)
bacteria of opposite “sexes” physically contact one another and exchange genetic information
lactose interacts directly with repressor protein and that is what causes the repressor protein to leave the DNA operator site
Inducible promoters (lac operon)
Transcription is active on these genes unless there is an excess of tryptophan. Here the repressor protein will only bind to the DNA and block transcription IF it is bound to tryptophan
Repressible promoters
Acellular (not comprised of a true cell) particles that have nucleic acid (genetic material) and proteins
are viruses outside of a host cell which is comprised of a nucleic acid genome on the inside of a capsid of proteins
phages that are temperate viruses and do the lysogenic cycle of infection. The viral genome is incorporated into the host cell’s genome making a prophage. The viral genome can be removed from the host cell genome which causes the viral genome to become active and start the lytic cycle of infection.
Lysogenic cycle
phages that are virulent and do the lytic cycle of infection. The viral genome takes over the transcription and translation machinery of the host cell. The end result the cell bursts and releases many newly made virions.
Lytic cycle
DNA sequence immediately adjacent to the promoter in the operon
The 1st DNA sequence in an operon
Is a gene that codes for any RNA or protein product other than a regulatory protein
Structural gene
A surface appendage by which some bacteria adhere to one another during conjugation.
infection by a phage
cells take in DNA in the environment through the cell membrane
Causing or capable of causing disease and death
these organisms are single-cellular individuals that reproduce asexually & have no true nucleus
refers to when and if the information in a gene is copied into
RNA and if that RNA (specifically in the case of mRNA) is translated into a protein.
If a gene is expressed then the end product of that gene is made
Gene expression
is an operon required for the transport and metabolism of lactose. It consists of three adjacent structural genes, a promoter and an operator. The lac operon is regulated by several factors including the availability of glucose and of lactose.
Lac operon
Contains the structural genes for making tryptophan (an amino acid)
Trp operon
A repressor is a DNA-binding protein that regulates the expression of one or more genes by decreasing the rate of transcription. This blocking of expression is called repression. Repressor proteins are coded for by regulator genes. Repressor proteins then attach to a DNA segment known as the operator. By binding to the operator, the repressor protein prevents the RNA polymerase from creating messenger RNA. If an inducer, a molecule that initiates the gene expression, is present, then it binds to the repressor protein and detaches from the operator. The RNA polymerase then can create the messenger RNA and allow the gene to be expressed.
Repressor protein
is only present on the DNA when glucose is absent and is bound to the promoter and this will recruit RNA polymerase which can transcribe the genes.
CAP (activator protein)