Exam 2 review Flashcards
Compare and contrast enhancers vs. promoters.
Enhancers are regions of the DNA where activator proteins (transcription factors) bind and speed up transcription
Promoters are DNA sequences that mark where transcription (and therefore gene expression) should take place.
They’re both in transription, but one marks where transcription should start and the other speeds it up.
Know the role of the sigma factor in transcription initiation.
They recognize and open promotors and begin RNA synthesis.
3) Understand the roles of the poly A tail in mRNA processing.
It increases mRNA stability and prevents degradation
4) Know the steps in translation initiation. Be sure to mention the following: initiator tRNA, small vs. large ribosomal subunit, start codon, first amino acid.
The initiator tRNA attaches to the start codon (AUG), the small subunit of ribosome binds to the mRNA, and finally, the large ribosomal subunit binds to create the initiation complex which allows the first amino acid to be created.
5) Understand the role of release factors in translation termination.
They recognize the stop codon and end the amino acis chain, which frees the polypeptide chain
Nonsense-
Codon changed to chain-terminating
7) Know the steps in doing a Gram stain and what might happen if you mess up a certain step.
Add crystal violet and wait for it to bind to all bacteria and wait for 1 min
Add iodine, which affixes crystal violet and wait for 1 min, then rinse
Add alcohol, which removes crystal violet from gram negative bacteria and wait for 15 seconds, then rinse
Add safranin (counterstain) and wait for 60 seconds
8) Distinguish between Gram positive and Gram negative bacteria in terms of their cell wall.
Gram positive have a thick peptidoglycan wall, and gram negative have a thin one in the periplasmic space between the inner and outer membranes.
10) Which bacterial phylum forms endospores, and what else is it known for?
Firmicutes, extremophile
11) Which bacterial phylum produces antibiotics, and what else is it known for?
Actinomycetota, high GC
12) Spirochaetota is a very goofy ahh phylum. Describe its traits.
Spirillum, gram-negative bacteria, chemoheterotrophic
13) Describe the traits of phylum Chlamydiota.
Diverse phylum with species found in the oceans, smaller than many viruses, oviod, gram-negative
14) Describe the traits of phylum Bacteroidota.
Gram-negative, non spore forming, found in soil, water, GUT MICROBES, on skin, rod shaped
Taxonomy is ___________ due to advances in genome sequencing technology!
always changing
17) Know how to perform the quadrant streaking method and its advantages.
Start with a lot of streaks, getting progressively fewer until you go from heavy growth to individual colonies, sterilizing between each round. It allows for a lot of bacterial growth but still allows you to observe bacterial morphology.
