Bio Question

[coffinhaed]

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I was going thru Kaplan test and one question popped up. It was asks which of the answer choices would be produced in 10 turns of calvin cycle.

The answer says 20 PGAL and in explanation it says its from 6 cardon dioxide and 6 rbp.

I thought in one cycle 3 molecules of rbp join 3 molecules of co2 to make 1 pgal in one cycle. What am I doing wrong??

THanks for the help

2009-2010 book practice test question number 13 BIO

 

[rnbaxter]

6CO2 + 6RuBP ---> 12PGAL

10PGAL recycled, 2PGAL released

10PGAL = 30 Carbons ----> 6 RUBP = 30 Carbons

2PGAL X 10 = 20

 

[coffinhaed]

6CO2 + 6RuBP ---> 12PGAL

10PGAL recycled, 2PGAL released

10PGAL = 30 Carbons ----> 6 RUBP = 30 Carbons

2PGAL X 10 = 20

so you are saying one cycle takes 6 CO2? to make 12 PGAL? There is a net gain of 2 and that cycle times 10 is 20 PGAL? That would require 60 CO2 then and it says 6

 

[rnbaxter]

so you are saying one cycle takes 6 CO2? to make 12 PGAL? There is a net gain of 2 and that cycle times 10 is 20 PGAL? That would require 60 CO2 then and it says 6

Well thats the correct explanation. I'm sorry you don't like it. Your books explanation is referring to the 1 cycle, so yeah technically 60 CO2s will be consumed.

 

[CANgnome]

Topscore and destroyer refer to 1 cycle as 1 CO2 consumed, so it is very wonky.

So my question is which is the correct choice: Does it take 6 turns of the calvin cycle to produce a glucose or 1? or 2 (2 G3P)?

 

[ToldYouSo]

Each turn of the cycle produces 1 net carbon, so it takes 6 turns of the calvin cycle to produce a glucose.

 

[RCT PC CRN]

Each turn of the cycle produces 1 net carbon, so it takes 6 turns of the calvin cycle to produce a glucose.

👍👍👍

10 turns of cycle will produce 10/3 PGAL (PGAL is 3 carbon) or sugar with 10 carbon.

Particular Q in Kaplan might be considering 1 cycle as when you produce 1 glucose so 10 cycle will produce 10 glucose or 20 PGAL. Q might have phrased badly.