Hi Moiz,
I've got answers to most of your questions. Hopefully another instructor can chime in with the rest. 😊
Q8: This is a question of elimination.
We want phosphorus. Protein is a great source of nitrogen. No amino acids contain phosphorus.
Hydroxyapatite is used in some toothpastes. Don't eat toothpaste.
Aminobisphosphonate is mentioned as being a bad thing in the passage. Don't eat that.
Phosphoric acid does contain phosphorus. Soft drinks have this as an additive to give a yummy sharp taste. But, there isn't much phosphorus in there... For example, one diet pepsi has 30 mg, or 2% of your RDA of phosphorus.
So, by process of elimination, it's gotta be C. Also, do RNA and DNA have phosphorus in them? Oh yeah. Phosphate groups!
Q12: In the concentration from 0.1 to 1 ng/mL, we have an almost linear graph (very easy to get a mathematical equation to represent that section) AND a very large change in intensity. These are both great things!!
From 0.1 to 100 ng/mL, we barely gain any change in intensity compared to the previous case, and we also have a much more complicated mathematical model (logarithmic? two straight lines combined?).
So, answer D is the best.
Q29: C isn't an amino acid. The question states that you need to start with an amino acid.
Q36: D is already included in the experiment as a negative control (look at the last line in the chart, with Cut6 -- it retains 100% residual activity).
So, B is the best answer.
Q41: Let's do the math.
At 37°C (physiological conditions), Kw = 10^-14, [H+] = 10^-7, so pH = 7.
Let's crank things up: Kw = 100 x 10^-14 = 10^-12, [H+] = 10^-6, so pH = 6.
The pH has decreased by 1 unit.
Q42: An unbalanced force is when Fnet is not equal to zero.
So, if Fnet != 0, then Fnet = ma, which is Newton's second law.
When Fnet = 0, we have Newton's first law (inertia!).
Q50: You're right, it's only a glucose monomer. This reaction takes glycogen and breaks it up into glucose subunits. That's the purpose of GP.
This question is very sneaky. The big thing that I looked for was "is there any time that a hydrogen got moved?"
Yes.
From the first step to the second step, a hydrogen was "kicked out" from the phosphate group.
It is very subtle, but that's the answer to the question.
Q53: I'll use an analogy to explain this:
Consider 100 g of pure gold. You go get it appraised. Ooooh, you're gonna be rich!
Consider 95 g of gold tainted with 5 g of brass. You THINK it's still 100% gold. You go get it appraised. HEY. Why isn't it worth as much anymore?
Same idea as the question. 100% pure molecule has a HIGHER molecular weight than wet molecule. The water is "tainting" the molecule (because it is lighter) and bringing the average molecular weight DOWN.