[djiang87]

Hi guys,

Im doing this sample paper and i have a couple of questions im strugling with from the multiple choice part. Here they are:

Question: What is the approximate strength of hydrogen bonds in water (in KJ.mol-1)?
Answers are: A) 0.2 B) 2 C) 20 D) 100 E) 200
I think the answer is 20, 1 link i found stated it ranges from about 18-40. I just dont know how trustworth the site is though.

Question: In the watson-crick model for the DNA double helix (B form) how many hydrogen bonds are in the A-T and G-C base pairs?
answers are: A) 3-2 B) 3-3 C)  2-2 D) 2-3 E)none of the above
I think the answer is D for this one.

Questions: A good transition-state analog:
A) Binds covelently to the enzyme B) Binds to the enzyme more tightly than the substrate C) Binds very weakly to the enzyme D) is too unstable to isolate E) must be almost identical to the substrate
This one im not sure about. Every link i found would just give a definition which didnt really help be to obtain an anwer.

Any help would be much appreciated. Ill probably have more questions to add either tonight or tommorrow as i havent started the short answer questions yet.

[AWK]

_{Question: What is the approximate strength of hydrogen bonds in water (in KJ.mol-1)?
Answers are: A) 0.2 B) 2 C) 20 D) 100 E) 200
I think the answer is 20, 1 link i found stated it ranges from about 18-40. I just dont know how trustworth the site is though.}


http://www.lsbu.ac.uk/water/hbond.html

Question: In the watson-crick model for the DNA double helix (B form) how many hydrogen bonds are in the A-T and G-C base pairs?
answers are: A) 3-2 B) 3-3 C)  2-2 D) 2-3 E)none of the above
I think the answer is D for this one.

http://en.wikipedia.org/wiki/Base_pair

Questions: A good transition-state analog:
A) Binds covelently to the enzyme B) Binds to the enzyme more tightly than the substrate C) Binds very weakly to the enzyme D) is too unstable to isolate E) must be almost identical to the substrate
This one im not sure about. Every link i found would just give a definition which didnt really help be to obtain an anwer.

http://wiki.answers.com/Q/Why_are_transition_state_analogs_good_inhibitors