Dat Aciever Question--Bio and Org.

[Lonely Sol]

I had a question about this two questions fron DAT achiever.

The first one, the right answer is C but i always thought that endergonic rxn are coupled so the reaction would proceed, which would make D the correct answer. If anyone could explain, I would appreciate it.
The second one, The answer is A, but i thought CL would be more stable at secondary position instead of primary making C the correct answer.

1) Adenosine triphosphate (ATP)

A. can never be regenerated after its hydrolysis to ADP and Pi.
B. is thermodynamically more stable than its products of hyrolysis.
C. powers cellular work by coupling exergonic reaction to endergonic reaction.
D. powers cellular work by coupling endergonic reaction to exergonic reaction.
E. contributes little to the driving of cellular work.



2) Which product will be formed in majority through the following addition reaction?

CH2=CHCH=CH2 + HCL@ 25 degreeC ----->
A. CH3CH=CHCH2Cl
B. CH3CH=CClCH3
C. CH3CHClCH=CH2
D. CH2ClCH2CH=CH2
E. CH3CH2CH=CHCl

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[TEXDENT]

exergonic rxns are coupled to drive endergonic rxns, and hydrolysis of ATP is an exergonic rxn. therefore its hydrolysis is coupled to the endergonic reaction that can't proceed without it.

But I see what you are saying, I really think the wording "coupling" would make either answer fit.

a better word would be to substitute "drives" for "coupling" and then it would read that exergonic drives endergonic which is choice C

 

[Gasedo]

I had a question about this two questions fron DAT achiever.

The first one, the right answer is C but i always thought that endergonic rxn are coupled so the reaction would proceed, which would make D the correct answer. If anyone could explain, I would appreciate it.
The second one, The answer is A, but i thought CL would be more stable at secondary position instead of primary making C the correct answer.

1) Adenosine triphosphate (ATP)

A. can never be regenerated after its hydrolysis to ADP and Pi.
B. is thermodynamically more stable than its products of hyrolysis.
C. powers cellular work by coupling exergonic reaction to endergonic reaction.
D. powers cellular work by coupling endergonic reaction to exergonic reaction.
E. contributes little to the driving of cellular work.



2) Which product will be formed in majority through the following addition reaction?

CH2=CHCH=CH2 + HCL@ 25 degreeC ----->
A. CH3CH=CHCH2Cl
B. CH3CH=CClCH3
C. CH3CHClCH=CH2
D. CH2ClCH2CH=CH2
E. CH3CH2CH=CHCl

In addition rxns of conjugated dienes HCl can add at position 1, 4 or 1, 2. Internal alkenes are more stable that terminal ones.
Answer A represents internal, 1,4 addition.

 

[Lonely Sol]

Thank you so much for explaning, really appreciate it