either too careless or too careful and making mistakes on B/B. please help!

[MC789]

I am pretty frustrated at this point because I'm getting questions wrong either being too careless or too careful, for even the standalone questions which I have content knowledge for. any advice would be greatly appreciated!

so for the first question, 64, I missed the part in the question that said PROTEIN and thought it was asking about gene/dna levels and so selected A.

From this, I learnt from this mistake and carefully read each word of the questions and considered all the relevant passage info to eliminate answer choices. for the second question, 74, this was my thought process: complete removal of PT glands -> no PTH in body -> lower levels of Ca in plasma BUT question doesn't mention removal of Vitamin D. Vitamin D is still available and that causes Ca to still exist in plasma. So there won't necessarily be a DEFICIENCY of plasma Ca and hence A can be ruled out. B and D are obviously wrong since the opposite is true. I felt C made sense because no PTH -> no breakdown of bone -> higher than usual mineral amount in bone. Vitamin C is still there and synthesizes bone matrix. so in this special case of no PTH, the usual mineral to matrix ratio is changed due to increase in mineral amount from the lack of PTH.

can someone please explain where I am wrong and how to strike a balance between being careful, but not so careful that I make illogical connections? I've been practicing passages everyday but can't seem to improve in this area of thinking.

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[pretty_positron]

You're overthinking this. But if you do want to overthink it, you should realize that vitamin D improves the absorption of dietary calcium in addition to aiding PTH. Since PTH is gone, it only does the first function. This doesn't operate in a feedback loop - it isn't as though the loss of PTH will cause vitamin D to be upregulated and increase the absorption of dietary calcium. This is essentially a constant.

So without the parathyroid and without PTH you will have less serum calcium.

Your answer won't work because nothing is affecting the mineral-matrix ratio in bone tissue. This is only affected by PTH which acts on the osteoclasts, and vitamin D indirectly by aiding the effect of PTH. Vitamin D itself doesn't affect the bones themselves.

As for the cyclin question, regardless of whether you read "protein" or not, you should know that gene/DNA would increase at the S-phase (middle portion of interphase) and then sharply decline at the end of mitosis once cytokinesis occurs. This would occur rather than the gradual increase of cyclin during interphase (indicating translation of proteins) and then gradual decline during mitosis (indicating breakdown of the spindle apparatus).

 

[CommyO]

For PTH, you just have to know that Calcitonin and PTH are antagonists. The former decreases calcium in blood while the latter increases it