Various TS and Achiever Q's- DAT 2morrow!

[tawaqul]

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Let me just say that first of all, I didn't think I would have so many questions the day before my exam and it is making me extremely nervous, but if anyone takes out the time to answer any or all, I will truly be appreciative.My retake is tomorrow and I will be typing out probably the most thorough breakdown of anyone, unless of course I'm really pissed or something, which I am telling myself I WILL NOT BE no matter what!

Again, to anyone who answers these, thank you SO MUCH!🙂

TS Test 2:

1. BIO #38 (vs #2 in TS 3). It says that energy is used in the Calvin Cycle in conversion of ATP to ADP, where energy is produced in the Krebs Cycle when ADP converts to ATP. But in #2 of TS 3, it says that converting ADP to ATP is endergonic and does NOT release free energy. Confused! Why are they contradicting each other?

TS Test 3:

1. GCHEM #58, it says: What is the difference between 1st order and 2nd order rxns when considering 1/2 lives? Answer: t1/2 is independent of concentration for all 1st order rxns. I don't get where they are going with this problem. What am I supposed to understand?

Achiever Test 1:

1. QR #12, it says: What will be the likelihood of having 1 boy in a family planning for 3 children? Answer: 3/8. Why is it a permutation here? Why does order matter? I'm getting really confused as to when to use a combination, permuation and then sometimes it's simply 1 factorial divided by another.

Achiever Test 2:

1. BIO #8, it says that ATP powers cellular work by coupling exergonic rxn to endergonic rxn. Why not the other way around?

 

[tawaqul]

Ok i edited out the questions I got help with and understand now. Anyone want to try the ones that are left?

Thanks!

 

[predent270808]

I double check in the book and also some sources on the web. Hydrolysis of ATP to ADP is exgothermic , not endo. They made mistake.

Achiever: do not get stuck to the permutation or combination here. think it in simple way. Among boy and girl in the planning to have 3 children, we have 2X2X2 = 8
the probability to get boy is 3/8
If they did not ask you the way to arrange something. I think you shouldnot think about permutaion or combination.

Achiever2: it is correct, hydrolysis of ATP give energy for other rxn .

the equation for t half life is .693/k . It is depend on the rate constant only.