Question

What are the 3 main processes of aerobic respiration and in which part of the cell (specifically) do they occur in both prokaryotes and eukaryotes?

Answer 1

There are three main processes involved in cellular respiration, separated into two phases
The first part is called glycolysis. Are you familiar with glycolysis?

Glycolysis takes place in the cytoplasm of a cell.
It involves the enzymatic breakdown of glucose into 2 pyruvate molecules.
There are about 10 enzymes involved in this process

This process requires 2 ATP molecules to get started, but it produces 4 ATP molecules. Therefore, there is a net of 2 ATP produced
Also, 2 NADH molecules are produced

From glycolysis, there are two available pathways
The anaerobic pathway will result in the regeneration of NAD+ from NADH. The process involved is commonly known as fermentation. However...
...we will focus on the aerobic pathway, which leads us to another part of the cell.

In eukaryotes, these processes (Krebs cycle and electron transport chain/oxidative phosphorylation) take place inside of a specialized organelle. Any idea what organelle that might be?

Answer 2

The mitochondrion is the organelle where the final two aerobic respiration processes (Krebs cycle and ETC/Ox-Phos) take place
In a prokaryote, the location will differ because prokaryotes don't have organelles
So... their respiratory processes take place across their cell membranes

First step of aerobic process is converting the pyruvate molecules that are shuttled out of the cytoplasm and into the mitochondrion (or to the cell membrane for prokaryotes) into a carrier molecule called acetyl-CoA

After acetyl-CoA has been made, then it will combine with oxaloacetate to create citrate. From this point, the Krebs cycle begins
After acetyl-CoA has been made, then it will combine with oxaloacetate to create citrate. From this point, the Krebs cycle begins
During Krebs cycle, there are a number of reactions that take place

Answer 3

During the Krebs cycle, there will be 4 units of CO2 produced
Combined with the 2 units produced during acetyl-CoA formation, and that yields six units (or moles) of CO2. This number is significant because it tells us that combustion of glucose will yield six moles of carbon dioxide (and six moles of water, which will be produced later)

Also, 2 turns of cycle produces 6 NADH molecules, 2 FADH2 molecules, and 2 ATP molecules

The six NADH and 2 FADH2 molecules will be shuttled from the matrix of the mitochondria to the inner membrane (for eukaryotes), where the electron transport chain is located
For prokaryotes, these processes continue to take place across cell membrane

Answer 4

During the electron transport chain, NADH from both glycolysis and Krebs cycle, as well as FADH2 from Krebs cycle, will pass their electrons through a series of membrane-embedded protein complexes.

The electron transport chain. It takes place across the inner membrane of the mitochondrion

Answer 5

As the electrons pass through each protein complex, protons (H+) are pumped out of the matrix and into the intermembrane space to create a proton gradient.

Each complex is called a cytochrome (except for the large one at the end) --------------------> http://prntscr.com/4tjeof
With the exception of the small yellow one, they're supposed to be around the same size.

As electrons enter and pass through each complex, a series of oxidation-reduction reactions will take place. So what you'll see is a transport of electrons down a "chain" of membrane-bound proteins.

It was said earlier that the protons (H+) are pumped out because we want to create a concentration gradient.

A concentration is essentially a difference in concentration of a substance in two different areas. For instance, if you have a bunch of stuff in your closet and not so much outside of your closet, then you could say that you have a higher concentration of stuff in your closet than in the rest of your room.

^ This would create/establish a concentration gradient.Substances like to flow from areas where their concentrations are high to areas where their concentrations are low.
In the case of a junky closet, the contents are likely to spill out at some point.
That's kind of what takes place with a concentration gradient.

Answer 6

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^
Here, because there are so many more protons in the intermembrane space after they've been pumped into the space, these protons are going to want to flow back across the membrane back into the matrix. So they'll re-enter the matrix by flowing through the large complex on the far right--called the ATPase

The process of H+ flowing down the concentration gradient will then provide enough energy to form ATP from ADP and inorganic phosphate

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Answer 7

Also, the electrons that passed through the ETC will reduce oxygen to water -----------------> http://prntscr.com/4tjgl5

Answer 8

In all, about 30-36 ATP molecules are formed during the three-stage process (glycolysis, Krebs cycle, and oxidative phosphorylation/electron transport chain).

Answer 9

And so, the difference between this process taking place in eukaryotes and in prokaryotes is that in eukaryotes, glycolysis takes place in cytoplasm and Krebs cycle and Oxidative phosphorylation/electron transport chain take place in the mitochondrion (mitochondria plural)

Whereas in prokaryotes, glycolysis will still take place in the cytoplasm, but Krebs/oxidative phosphorylation/electron transport chain will take place across cell membrane

Answer 10

Notes and diagrams+summary on what I've stated above, I've written it on a board, so that its easier for you to visualize and therefore, you can print it out and review it.

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Whew--that was a full mental workout :) It seems like a lot to learn initially, but it'll all make sense once you review/practice. I promise.