biology Q

[c3p]

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from kaplan book:

11) which of the following is involved in respiration and excretion, and develops into the placenta in humans?

a) chorion
b) allantois
c) amnion
d) yolk sac
e) placenta



A: b

i thought that the chorion developed into the placenta and is for gas exchange (while the allontois develops into the umb. chord and is for waste)...

cliffs AP said it was chorion so i was wondering how im wrong...thanks.

 

[hausee]

http://en.wikipedia.org/wiki/Chorion
........ The chorionic villi emerge from the chorion, invade the endometrium, and allow transfer of nutrients from maternal blood to fetal blood....

http://en.wikipedia.org/wiki/Allantois
......It helps the embryo exchange gases and handle liquid waste..........

 

[iDreamofDent]

you just said you thought it was chorion and cliffs said chorion, are you sure?

I know the allantois is close enough to the surface in birds and reptiles to act as a receptacle for nitrogenous wastes and function in respiration, but you are right as in humans it develops into the umbilical cord.

 

[dds10]

In Cliffs:
Allantois = gas exchange and transports waste products to placenta. It forms the umbilical cord, transporting gases, nutrients and wastes between the embryo and the placenta.
Chorion = gas exchange and forms the placenta where gases, nutrients and wastes are exchanged.

Its a tricky question :S ??😕

Also, the explanation at the back says ... "Later during development, the vessels enlarge and become the umbilical vessels, which will connect the fetus to the placenta."
I think the question is not worded properly.

 

[c3p]

if i got it on my dat i dont know what i would put...if it said waste id put allontois if it didnt i probably put chorion...i dont know whats correct which sucks. choulda sworn i saw chorion in more than one place as the answer.

 

[allstardentist]

at least for my DAT, every question had a clear cut answer for every section

 

[fishstalker73]

from kaplan book:

11) which of the following is involved in respiration and excretion, and develops into the placenta in humans?

a) chorion
b) allantois
c) amnion
d) yolk sac
e) placenta



A: b

i thought that the chorion developed into the placenta and is for gas exchange (while the allontois develops into the umb. chord and is for waste)...

cliffs AP said it was chorion so i was wondering how im wrong...thanks.

The question asked which of the following will develop into the placenta in humans. The chorionic tissue along with the maternal uterine tissue will develop in the placenta in humans and not the allontois. I would chose A as the answer based on the specificity of the question.