What happens to the 3-carbon compounds that do not leave the Calvin cycle to be made into organic compounds?

Answer 1

The glyceraldehyde-3-phosphate (#"G3P"#) that is not used to make organic compounds is turned into ribulose-1,5-bisphosphate (#"RuBP"#) to be recycled.

In the first two stages of the Calvin cycle — carbon fixation and reduction — 3 molecules of #"RuBP"# and 3 molecules of #"CO"_2# are converted into 6 molecules of #"G3P"#.

(From www.khanacademy.org)

#"3RuBP" + color(white)(l)"3CO"_2 → "6G3P"#
#"3×5C"color(white)(ll) + "3×1C" → "6×3C"#

However, only one of the #"G3P"# molecules goes to make other compounds.

The other five are recycled to regenerate RuBP.

#"5G3P" →color(white)(l) "3RuBP"#
#"5×3C" →color(white)(l) "3×5C"#

The net result is that 3 molecules of #"CO"_2# are converted to 1 molecule of #"GDP"#:

#color(red)(cancel(color(black)("3RuBP"))) + "3CO"_2 → stackrelcolor(blue)(1)color(red)(cancel(color(black)(6)))"G3P"#
#color(red)(cancel(color(black)("5G3P")))color(white)(mmmmm) → color(red)(cancel(color(black)("3RuBP")))#
#stackrel(————————————)("3CO"_2color(white)(mmmmmll) → "1G3P")#

By signing up, you agree to our Terms of Service and Privacy Policy

Answer 2

Eli Ayoub

The regeneration phase of the Calvin cycle recycles the 3-carbon compounds that do not exit the cycle, guaranteeing the cycle's ongoing operation.

By signing up, you agree to our Terms of Service and Privacy Policy

Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.