Tutor profile: Kate R.

What are some examples of in vivo exceptions to the biochemistry mantra, "DNA becomes RNA becomes protein"?

1) Retroviruses! They use the enzyme reverse transcriptase to assemble DNA from their genomic RNA. By converting viral RNA into DNA, the virus can use the hosts' DNA replication and transcription/translation machinery to produce more of itself. 2) Inserting retrotransposons into the genome of eukaryotes, which helps increase genetic diversity. This is a really weird phenomenon that is similar to lateral gene transfer in bacteria - we can talk about it more if you're interested! 3) Replicating telomeres: the proteins involved in telomere synthesis contain an RNA template. This process helps maintain the stability of eukaryotic chromosomes. Here's some more information: https://www.thermofisher.com/us/en/home/life-science/cloning/cloning-learning-center/invitrogen-school-of-molecular-biology/rt-education/reverse-transcription-basics.html

My grades aren't perfect, but I'm really awesome! How do I show this to a university?

Okay, I have some questions for you: how imperfect are your grades, and to what extent do grades matter for where you're applying? Some places have firm cutoffs for GPA, so if you apply with a GPA lower than this cutoff, your application will be screened out. This is something to check before you apply. However, most places that have a recommended GPA aren't exactly like this: depending on the number and quality of other applications they receive, there is a chance they will look at most or all applications. In this case, assuming your grades are close to what they're looking for, grades matter less than your letters of recommendation, your personal statement and motivation for applying, and your experience doing the thing you're applying to do - more or less in that order. So, let's take a look at the materials you have and polish them up!

What's the difference between classically activated and alternatively activated macrophages?

Classically activated macrophages are proinflammatory: they mediate host defenses against viruses, but also promote injury to tissues through the production of signalling molecules such as NO (nitrous oxide), IL-1, IL-6, IL-8, and TNF. They promote (non-exhaustively) inflammation, extracellular matrix destruction, and apoptosis. Alternatively activated macrophages are anti-inflammatory: they regulate wound healing by producing matrix metalloproteases, growth factors, and anti-inflammatory cytokines. They promote (non-exhaustively) extracellular matrix construction, angiogenesis, and cell proliferation. Here's a good resource, for a more thorough answer: https://www.rndsystems.com/resources/articles/macrophage-activation