Login

Welcome, Guest. Please login or register.

March 29, 2024, 12:28:48 pm

Author Topic: Photophosphorylation, RUBP and the Calvin cycle.  (Read 1629 times)  Share 

0 Members and 1 Guest are viewing this topic.

--whiteskies

  • Victorian
  • Trendsetter
  • **
  • Posts: 104
  • Respect: +1
  • School: Mac.Robertson Girls' High School
  • School Grad Year: 2014
Photophosphorylation, RUBP and the Calvin cycle.
« on: March 16, 2013, 11:41:01 pm »
0
What is this cyclic/non-cyclic phosphorylation they speak of in textbooks? :'(
How much depth do we need to go through?

+ also please people, explain to me calvin cycle in basic words D:
SOBBING.

and this RUBP thing they talk of D:

Thanks! :)
[2013]: Biology | Mathematical Methods (CAS)
[2014]: Chemistry | Psychology | English | Further Mathematics | UMEP Biology
[2015]: Biomedical Science @ Monash

Tutoring for Psychology and Further Mathematics - PM for details!

alondouek

  • Subject Review God
  • Honorary Moderator
  • ATAR Notes Superstar
  • *******
  • Posts: 2903
  • Oh to be a Gooner!
  • Respect: +316
  • School: Leibler Yavneh College
  • School Grad Year: 2012
Re: Photophosphorylation, RUBP and the Calvin cycle.
« Reply #1 on: March 16, 2013, 11:51:44 pm »
+1
1. Phosphorylation not really essential to know - just maybe look at the outputs of oxidative phosphorylation and how it ties into respiration as a whole.

2. The Calvin Cycle is a sequence of redox reactions that take place during the light-independent stage of photosynthesis (i.e. the 'second' part of photosynthesis) - hence it occurs in the stroma of the chloroplasts. Basically, it is used to fixate carbon - that is, to take carbon from gaseous CO2 and convert it a form that is usable by the plant.

Outputs of Calvin Cycle (not necessary, but interesting): 2x G3P molecules (the 'usable carbon' form mentioned above), 3x ADP (and therefore 3x Pi) and 2x NADP+ molecules.

3. RUBP is just a molecule that is part of one of the steps in the Calvin Cycle. Don't worry about knowing anything more than that.
2013-2016
Majoring in Genetics and Developmental Biology

2012 ATAR: 96.55
English [48] Biology [40]

Need a driving instructor? Mobility Driving School

psyxwar

  • Victorian
  • Part of the furniture
  • *****
  • Posts: 1354
  • Respect: +81
Re: Photophosphorylation, RUBP and the Calvin cycle.
« Reply #2 on: March 17, 2013, 09:46:28 am »
0
Photophosphorylation is simply phosphorylation (the addition of a phosphate group to a substance, in this case to ADP) using light energy. I honestly doubt you'll need to know cyclic and non-cyclic phosphorylation, but basically:

- In non-cyclic photophosphorylation, the excited electrons go through the electron transport chain, producing ATP and eventually being accepted by NADP+, while in cyclic photophosphorylation, the electron goes through a "cycle" and is thus recycled. ATP is still produced, but because the electrons don't end up being accepted by NADP+, no NADPH is produced

- I'm pretty sure since the electron gets recycled, water doesn't need to be broken down for its electron and therefore O2 isn't an output

- Non-cyclic photophosphorylation involves two "photosystems" which are just protein complexes involved in the light-dependent stage of photosynthesis -- they're responsible for absorbing the light (via chlorophyll) and they facilitate the electron transport chain which produces the ATP. Cyclic photophosphorylation on the other hand only involves one photosystem. Bacterial photosynthesis involves only one photosystem and therefore they use cyclic photophosphorylation.

Though you probably don't need to know this, RuBP is ribulose biphosphate and its a 5 carbon sugar that's involved in the Calvin Cycle. The G3P molecules alondouek was talking about you might know as the PGALs (3 carbon sugars).

If you have the time I really recommend checking these videos out: https://www.khanacademy.org/science/biology/photosynthesis

They do go into more depth than necessary for the 3/4 Biology course, but I think it helps you understand the actual processes more meaning you have a better idea of what actually happens in say, the Calvin Cycle.
« Last Edit: March 17, 2013, 09:54:08 am by psyxwar »
VCE 2013-2014
MD/BMedSci 2015-2020