MYTUTOR SUBJECT ANSWERS

233 views

How does the Calvin Cycle in photosynthesis work?

If you recall the basic chemical equation for photosynthesis: CO2 + H2O --> O2 + Carbohydrate (with 6-Carbons)
​This is precisely what occurs during the calvin cycle. Carbon dioxide is fixated and at the end, the whole purpose of the cycle is to produce a carbohydrate integral to the plant, like Sucrose.

The process of the calvin cycle (light-independent stage) occurs in the Stroma of the chloroplast. It uses the products of the light-dependent stage (ATP and NADPH) in order to carry out the cycle.

Firstly, CO2 is fixed by a special enzyme called RuBisCo. The carbon atom from the CO2 molecule is added to the 5C molecule (Ribulose-1,5-bisphosphate) to form an unstable 6C molecule which then splits in half to form two 3C molecules (this 3C molecule is called 3-phosphoglycerate). Then, ATP is introduced (remember: the ATP came from the previous light-dependent reactions). The ATP loses a phosphate group to the 3C molecule - ADP is formed as a result and the 3C molecules become 1,3-bisphosphoglycerate. The 1,3-bisphosphoglycerate is then reduced by NADPH (NADPH is itself oxidised during the process) to form GALP, also known as Glyceraldehyde-3-phosphate. One Carbon atom from GALP is removed in every cycle - this carbon will contribute to the creation of the desired 6C carbohydrate (therefore, 6 cycles of the calvin cycle are needed to form the carbohydrate). We have 5 carbons remaining - the Ribulose-5-phosphate is then regenerated. Lastly, ATP will donate a phosphate group to the 5C Ribulose which will then form Ribulose-1,5-bisphosphate, which brings us back to square one. The cycle then repeats.

Kartika A. A Level Biology tutor, GCSE Biology tutor, A Level Chemist...

5 months ago

Answered by Kartika, an A Level Biology tutor with MyTutor


Still stuck? Get one-to-one help from a personally interviewed subject specialist

116 SUBJECT SPECIALISTS

£20 /hr

Zoe C.

Degree: Biological Sciences (Bachelors) - Exeter University

Subjects offered: Biology, Geography+ 1 more

Biology
Geography
Chemistry

“My name is Zoe and I am currently studying biological sciences at the University of Exeter. I absolutley love science and I would love to tutor you so you can discover the wonders of science too. At A level I studied biology, chemistr...”

£20 /hr

Victoria S.

Degree: Physiology (Bachelors) - Liverpool University

Subjects offered: Biology, Maths

Biology
Maths

“About me:Hey! My name is Tory and I am in my second year studying Physiology in the School of Life Sciences at The University of Liverpool. After completing my current degree, I hope undertake a Graduate-entry Medicine course to furt...”

£20 /hr

Odette F.

Degree: Biological Sciences (Bachelors) - Exeter University

Subjects offered: Biology, Geography+ 1 more

Biology
Geography
-Personal Statements-

“ABOUT ME: I am a 2nd Year Biology Student at the University of Exeter. Science as a whole, is a subject I am hugelyenthusiastic about and I would love to share this eagernesswith you! Having spent some of my Gap Year teaching abroad, I...”

About the author

Kartika A.

Currently unavailable: until 06/09/2016

Degree: Chemical Engineering (Bachelors) - Bath University

Subjects offered: Biology, Chemistry

Biology
Chemistry

“When it comes to teaching others, I am extremely patient and will put every bit of effort into ensuring that whoever I'm teaching fully understands the concept I'm trying to explain. I don't want my students to leave a session with a ...”

MyTutor guarantee

You may also like...

Posts by Kartika

How does the Calvin Cycle in photosynthesis work?

Why does HCl dissociate in water but not in methylbenzene?

Why is it important to regulate body temperature? What is the role of our skin in regulating our body temperature?

Other A Level Biology questions

How does PCR work?

Suggest how natural selection has increased the number of resistant bacteria strains in hospitals

Name the three components of a nucleic acid

What are enzyme inhibitors?

View A Level Biology tutors

Cookies:

We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok