does the Formation of trophoblast come b4 or after the development of a three-layered embryo

I like ur questions pistolpete. They are really good revision. The trophoblast starts to form loong before the development of the germ layers. They are cells that form the outer layer of the blastocyst--this is cell division, so it begins to form from that time.

good job....

heres another questions
Achiever test1 question 21 says Proton pumps (being powered by exergonic reactions such as ATP depletions, electron transport chain redox series, etc...)

top score test 3 bio question 2 says that hydrolysis of ATP from ADP and inorganic phosphates: A.drives cellular work *I AGREE*
B.is an exergonic process

so wouldnt that make B right as well?

good job....

heres another questions
Achiever test1 question 21 says Proton pumps (being powered by exergonic reactions such as ATP depletions, electron transport chain redox series, etc...)

top score test 3 bio question 2 says that hydrolysis of ATP from ADP and inorganic phosphates: A.drives cellular work *I AGREE*
B.is an exergonic process

so wouldnt that make B right as well?



yea thats true it should also be B, but i got confused when it says ATP from ADP, shouldnt it be ADP from ATP??

Uhm..hmmm..... well, though both answers are indeed correct I would go with B rather than A because A is a little bit on the broad side. The process does release energy (exergonic) which is work but naturally, whatever process it could have been if it weren't exergonic would require cellular work just the same. So...method of elimination, I'd chose B.

well in the solution it said regeneration of ATP from ADP is enderogonic process,....thats wrong right

Pete in the third test it talks about atp FROM adp this is endo, but going from atp TO adp is exo . ATP is what does work spontanoeous so to be spontaneous, its needs to have a -G value, or exo