types of operons
What does it mean to be a positive operon
the regulatory protein is an activator
what operon components are associated with the lac operon?
lacZ - B-gal
lacY - permease
lacI - repressor
lacP - promoter
lacO - operator
what type of operon is the lac operon?
negative inducible
what types of transcription factors are associated with what types of promoters?
regulatory promoter = other transcription factors
core promoter = general transcription factors
what does it mean to be an inducible operon
usually off and can be turned on
what is a superrepressor?
the superrepressor is constantly on, so the operon is always repressed
what are the functions of B-galactosidase and permease
B-gal: breaks down lactose into glucose and galactose. also converts lactose to allolactose
permease: carries lactose into the cell
what is the role of peptidyl transferase?
forms peptide bonds between amino acids during translation
is the regulator of a negative represible operon made in the active or inactive form?
inactive!
what effect does DNA methylation have on gene expression?
the gene is repressed
when lactose is present, some is converted into____. What does this do?
allolactose
What is the role of EF-Tu in translation elongation?
Elongation factor that helps bring in charged tRNA molecules
What type(s) of operon would be most affected by a mutation that causes an activator to always be inactive?
positive repressible and positive inducible
what is meant by partial diploid?
bacterial cells that have two lac operons
in the presence of lactose, will you see B-gal and/or permease with the following mutations...
I+P+O+Z-Y- / I-P-O+Z+Y+
no B-gal or permease
explain the roles of the 5' cap and the poly A tail
5' cap - helps with binding of ribosome to mRNA in eukaryotes. also stability
poly A tail - main function is for stability/preventing degradation. also assists 5' cap during ribosomal binding