*SAT Subject Test Biology E/M June 2016 Discussion Thread*

Thank god it was chemical that’s what I thought but I was torn between that and electrical

But wasn’t an answer choice the synapse which is the signal that is transmitted at the neuromuscular junction

Is a 72/80 a 750 +?

On e

For the one about the insect population and the decomposing tree, my reasoning was that insects use trees as a habitat (they actually don’t decompose anything for food – they’re classified as arthropods), so the population would be the inverted bell curve (population crashes as a result of tree falling, then it will regenerate quickly, as insects reproduce quickly).
I don’t know why the insect population would regenerate during the decomposition of the tree (so maybe my reasoning was flawed), but it also doesn’t make sense to me as to why the insect population would increase…
Anyone want to discuss with me?

Also, for the one about frogs detecting toxins in the environment… was it the choice with the permeable skin? I didn’t put it, but in retrospect I’m thinking that it might have been.

Also for the insect question I think it should be the linear decreasing curve only because the other options had the population increasing at one point in time which is not possible if they use the tree as their habitat because they will die when it is decomposed. And for the enzyme question it has to be that the substrates are used up because if the active sites were all filled then the product would still be produced but it wasn’t be there was seei growth in the product

Zero growth*

and @mastersuperfan for the antibodies on the M section, choice A) was something like: “It takes time for the chromosomes to rearrange themselves so that the antibody matching the foreign material”
I ended up with C) (I’m relatively sure) “The already differentiated lymphocytes need time to duplicate to provide a strong response.”
The reason is because B and T cells are already circulating throughout your blood, each recognizing a certain antigen. A response to the foreign antigen involves dendritic cells and macrophages presenting an antigen, which is then recognized by a B cell/helper T cell. A helper T cell stimulates more B cells and basically the B memory and plasma cells (the ones that secrete antibodies) are formed and etc…

@richsmith I believe the frog one was that it was cause of its skin because the other answer choices either applied to both or neither

@neehal120 yeah I considered linear decreasing for a second but the tree “falls,” so any decrease in population should be drastic, not linear.

what was the answer to the frog question? I said its BC frogs have lungs and fish have gills, but I’m pretty sure that’s wrong.

@richsmith yes but the other answer choices had an increase and the population would not increase fallowing the decomposition of the tree

@comeonmrtan I’m pretty sure it was the one about permeable skin

a search on google tells me that frogs are good indicator species (are affected by toxins) because they live on both land and water, with their thin skin absorbing toxic chemicals and radiation.

@neehal120 The synapse is only the junction between two neurons.

@richsmith Since the question was talking about insects that are specifically decomposers of the tree, they would swarm to the tree and reproduce exponentially first. The insects probably aren’t living in the tree since there’s not much to decompose there.

The question about the antibodies was referring to the first exposure to an antigen, correct? In that case, the immune system needs to discover an antibody that effectively inhibits the pathogen. I’m more confident in my answer now since I remember it was something we learned specifically in class.

Also, for the frog one, I said it was because of their permeable membranes. The other choices were illogical.

Does anyone that took molecular remember what you put for the question where it asked why the mutant bacteria was not able to produce galactidose

@comeonmrtan I put the same lol.

@neehal120 DNA mutation.

I put some mutation in the gene that produced galactidose?

That was the answer choice where it said that the nucleotide sequence in the gene that encodes for galactidose was incorrect, right cause I put that too