DAT Trap Questions...

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Jo07

Dingo
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I'm trying to start a thread here for all of us who will be taking the DAT soon.

Please add any questions/answers that you come across that are common 'traps'.

I'll start...

For questions on chiral molecules that ask you to decide between R or S and which direction it will rotate plane polarized light. Ans: R and S configuration doesn't give any indication of L or D! It has to be experimentally determined.


Good luck to everyone! :luck:
 
Its funny how 85 ppl saw this post but didnt post anything....ppl are getting competitive.😀

a trick question that got me, on a practice exam, was about enantiomers:

It showed an organic compound and simply asked for the number of enantiomers the compound had. The trick was that the compound was meso and so using the formula 2^n would trap you!
 
Its funny how 85 ppl saw this post but didnt post anything....ppl are getting competitive.😀

a trick question that got me, on a practice exam, was about enantiomers:

It showed an organic compound and simply asked for the number of enantiomers the compound had. The trick was that the compound was meso and so using the formula 2^n would trap you!

In case you're confusing them, 2^n will give you the number of stereoisomers.
 
I've got another one. Somebody tell me why this isn't correct.
"After the surge in LH, ovum will be released from follicular cell and then formation of corpus luteum will take place."
 
Is there a difference between follicular cells and a follicle? I know follicular cells release estrogen and progesterone in response to FSH. estrogen peaks followed followed by surge of LH and ovum is released from follicle which is composed of granulosa cells, thecka cells, and ovum.
 
I've got another one. Somebody tell me why this isn't correct.
"After the surge in LH, ovum will be released from follicular cell and then formation of corpus luteum will take place."

I believe the trap is that an ovum is not released... a secondary oocyte is released....
 
Both are correct. A secondary oocyte is released as opposed to ovum, and it is released from the follicle rather than follicular cells as well.

Damn, I am mighty impressed with SDN.
 
I dont think there is a difference between ovum and secondary oocyte. Its true that secondary oocyte is more specific, however the word "ovum" is also used. Ive seen it referenced to as the ovum in both kaplan and Schaums Bio
(pg 175)

interesting to note that the ovum is the largest cell in the human body (only one visible with the human eye). Probably another useless fact that i'll never need after I'm done with this test
 
Electron Affinities
Going across a period to the right, they tend to increase, HOWEVER, taking Period 3 as an example:

Mg < Na < Al < P < Si < S < Cl

Notice: Mg has ZERO electron affinity. Mg- is not stable because it would have to add electrons to a shell (2p) higher than its valence electrons (2s). This goes for ALL Group IIA elements.

Notice: P is actually lower in electron affinity than Si. In this case, there is electron repulsion in P- due to adding a fourth electron to 3p. A similar trend is observed with other Group VA elements.

These are exceptions to the rule of thumb. I just hope it doesn't come up on the exam.
 
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