9.12.2022. + 9.14.2022. IS questions Flashcards
what is quorum sensing?
sensing how many cells are nearby. flashlight in the stadium analogy where flashlights are gene expression.
how is antigenic variation different from phase variation?
antigenic variation: alteration in characteristics of certain surface proteins
phase variation: routine switching on and off of genes
what are the two components of a 2-component signaling system?
- membrane-spanning sensor
- response regulator
define genotype
genetic code. sequence of nucleotides in DNA
define phenotype
observed characteristics
can the genotype change without a change in pehnotype?
?!
can the phenotype change without a change in genotype?
yes
define spontaneous mutations
random genetic changes that arise from normal cell processes
why do doctors prescribe more than one drug for pathogens that develop antibiotic resistance?
a single mutation is rare. two mutations would be even more rare. prescribing 2 antibiotics means that there’s an even smaller chance that a single cell will become resistant spontaneously to both antibiotics
name the 3 mechanisms of horizontal gene transfer
- transformation
- conjugation
- transduction
which HGT process requires cells to be competent?
transformation
which HGT process involves a virus?
transduction
which HGT process involves a donor and recipient?
conjugation
what is the point of quorum sensing?
allows cells to activate genes that are only useful when expressed by a critical mass
what’s an example of something made by quorum sensing?
biofilms
