Conceptual Links Between Respiration and Photosynthesis

Let’s consider some conceptual links between the processes of aerobic respiration and photosynthesis.

1. Both processes are built around the same reaction:

2. Both processes are built around membrane proteins.

Photosynthesis

Respiration

Now, refer to these figures to spot the other links.

3. Both processes use several membrane protein complexes to couple electron transport along the membrane with proton transport through the membrane.

4. Both processes thus generate a proton gradient that is in turn used to run the ATP synthase.

5. Photosynthesis uses photons to generate high energy electrons while respiration strips high energy electrons from sugars (which were originally formed by reactions tied to photosynthesis).

6. Photosynthesis strips electrons from water to generate oxygen, while respiration donates the electrons to oxygen to form water.

7. Respiration strips electrons from an electron carrier, nicotinamide adenine dinucleotide (NADH):

nadh

NADH

while photosynthesis donates electrons to a closely related electron carrier, nicotinamide adenine dinucleotide phosphate (NADP):

nadp

NADP

8. Both processes use three basic protein complexes, with the same one occupying the central position – cytochrome bc1 and b6f.

9. Both process also use Coenzyme Q to transport electron from the first complex to the second.

10. In photosynthesis, the first complex uses photons to generate high energy electrons and couples this to stripping them from water; in respiration the first complex accepts high energy electrons from the electron carrier, NADH.

11. In photosynthesis, the last complex passes electrons to the electron carrier, NADP; in respiration, the last complex passes electrons to oxygen to form water.

12. Both respiration and photosynthesis are the only two established examples whereby endosymbiosis generated an organelle for eukaryotes – mitochondria and chloroplasts.


13. While neither respiration nor photosynthesis is essential for life, mitochondria made it possible to evolve animals and chloroplasts made it possible to evolve plants.

Oh my.

About these ads

One response to “Conceptual Links Between Respiration and Photosynthesis

  1. So cows and bunnies r responsible for global warming ;-)

    There is a video I watched once that asked Harvard graduates if they knew how a piece of wood from a tree was creatred. Some said dirt… yeah… they did.. nutrients, others said photosynthesis… oy vey….

    None could answer… and these are our brightest.

    I know u won’t agree Michael. But I tend to think the terraforming of earth was very rapid. I’m still not convinced of macro-evolution even with FL. Programmatically, FL makes more sense with variation on the edges.

    But what we observe today is rapid…
    http://en.wikipedia.org/wiki/Surtsey

    If I were some intelligent agent… why wouldn’t I terraform with fully functional seedlings and lifeforms? Why would I wait a billion years or more for any kind of evolution, FL or not?

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s