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Topic: some general concepts im confused about  (Read 7582 times)

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  • Guest
some general concepts im confused about
« on: January 23, 2005, 11:35:20 PM »
which of the following will most likely be disrupted by a change in pH?

1) hydrogen bonding
2) ionic bonding
3) hydrophobic interactions
4) disulfide bonds
5) neither

-I'm pretty sure its not 1) and 2) since changing the pH won't affect the electronegativity of an atom...Pretty sure that its not disulfide bonds either, so from that im guessing that its hydrophobic interactions..am i right? or is my concept wrong?

A nucleotide containing a purine, ribose, and a phosphate group could be a building block for?

a) dna
b) mRna
c) tRna
d) rRna
e) b,c,d

-Ok it is NOT A for sure, so im assuming that a nucleotide contaning a purine, ribose, and phosphate group could be a building block for all b,c,d....am i right ? or am i missing an important concept?

A DNA molecule with 5'ATCGTAC3' = 3'TAGCATG5'   right?

If one thousaidn glucose molecues arrive in a cell, and the 1000 glucose molecules join together into a starch molecue, what changes occured with the synthesis of the starch molecule?

-well this is an anabolic pathway since we are building something small into something bigger.  So entropy decreases, since this is a non-spontaneous system.  However, does the entropy of the universe decrease, or the entropy of the cell decrease?

Dehydration syntehisis will decrease entropy within a system right? since its the formation of smaller molecules into bigger ones?


  • Guest
Re:some general concepts im confused about
« Reply #1 on: February 03, 2005, 02:16:15 AM »
let's see if any of this helps

pH question - not 100% digging your answer - think about hair and perms - what are the chemicals used in perms - what is a neutralizer

RNA question - looks  right - dna is missing an hydroxyl group on the second C in ribose, hence deoxyribose
                      all three types of rna have that nucleotide structure - they do have differences, but not with the info you have given in the question

DNA structure question - at very quick glance - looks good - as long as you did the complementary base pairing right - the strands are opposite of each other

starch question- look at dehydration synthesis for the answer

entropy question - one step doesn't mean you climbed a mountain{meaning one reaction's entropy doesn't amount to much when dealing w/thousands of reactions (metabolic - entropy)}
an anabolic reaction is going to decrease entropy - increase PE
but in cells and the body reactions are coupled - so while an anabolic reaction decreases entropy, the catabolic reaction used to "power" it increased entropy - this continues until death of the cell/body when no more catabolic reactions can power the anabolic reactions - then entropy increases -

but the microbes/decomposers that are breaking done the cell/body are going through anabolic and catabolic reactions

I hope that I steered you in the right direction.

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