Top Posters
Since Sunday
I
3
3
p
2
w
2
y
2
J
2
Q
2
r
2
o
2
e
2
j
2
d
2
SlideshowReport

Noncyclic Pathway of Photosynthesis

Tags
Description
Noncyclic pathway of photosynthesis. Electrons that travel through two different electron transfer chains end up in NADPH, which delivers them to sugar-building reactions in the stroma. The cyclic pathway (not shown) uses a third type of electron transfer chain.

1 Light energy ejects electrons from a photosystem II.

2 The photosystem pulls replacement electrons from water molecules, which break apart into oxygen and hydro-gen ions. The oxygen leaves the cell as O2.

3 The electrons enter an electron transfer chain in the thylakoid membrane.

4 Energy lost by the electrons as they move through the electron transfer chain is used to pump hydrogen ions from the stroma into the thylakoid compartment. A hydrogen ion gradient forms across the thylakoid membrane.

5 Light energy ejects electrons from a photosystem I. Replacement elec-trons come from an electron transfer chain in the thylakoid membrane.

6 The electrons move through a second electron transfer chain, then combine with NADP+ and H+, so NADPH forms.

7 Hydrogen ions in the thylakoid compartment are propelled through the interior of ATP synthases by their gradient across the thylakoid membrane.

8 Hydrogen ion flow causes ATP synthases to attach phosphate to ADP, so ATP forms in the stroma.
Related Images
Add Comment
Explore
Post your homework questions and get free online help from our incredible volunteers
  841 People Browsing
Show Emoticons
:):(;):P:D:|:O:?:nerd:8o:glasses::-):-(:-*O:-D>:-D:o):idea::important::help::error::warning::favorite:
Your Opinion
Who's your favorite biologist?
Votes: 608