ATP outputs in aerobic respiration

[Bad Student]

This is pretty much exactly what the teacher covered in class. Is this really everything we need to know?

[Yacoubb]

This is pretty much exactly what the teacher covered in class. Is this really everything we need to know?

I'd say go to the VCAA website, open up a VCAA Unit 3 Exam and look at possible questions they ask, so as to give you an insight into the depth of knowledge you are required to know. Furthermore, I suggest consulting the trusty study design

[Russ]

I presume that it is because heart cells and kidney cells specialised for functions that require high ATP energy amounts to execute roles would have more mitochondria? I'm sure there is definitely a more complex explanation to this.

It's not that it's heart or kidney per se, it's the manner in which the transport occurs

If you're interested, see http://en.wikipedia.org/wiki/Malate-aspartate_shuttle (last paragraph in particular)

TLDR; it uses a more efficient mechanism for importing and thus maximizes ATP production

[Yacoubb]

It's not that it's heart or kidney per se, it's the manner in which the transport occurs

If you're interested, see http://en.wikipedia.org/wiki/Malate-aspartate_shuttle (last paragraph in particular)

TLDR; it uses a more efficient mechanism for importing and thus maximizes ATP production

Is this relevant to the Biology 3+4 course?

[Stick]

I also found out that 4 ATP molecules are synthesised in glycolysis and this is where the two 'excess' molecules come from.

[Yacoubb]

I also found out that 4 ATP molecules are synthesised in glycolysis and this is where the two 'excess' molecules come from.

So in cells specialised for functions that require high amounts of ATP expenditure (e.g. heart cells), there is a net output of 4 ATP molecules in Glycolysis.. I always thought that in the Electron Transport Chain, 32 -34 molecules of ATP were produced per glucose molecule.

[pi]

Is this relevant to the Biology 3+4 course?

Nope, that detail is uni bio level (probably not even first year uni bio)

[Russ]

Glycolysis doesn't differ between organs, it's a biochemical process where the same thing always happens (and yes, 4 ATP produced but net is 2)

[Bad Student]

Since the malate-aspartate shuttle regenerates NADH inside the mitochondrial matrix, it is capable of maximizing the number of ATPs produced in glycolysis (3/NADH), ultimately resulting in a net gain of 38 ATP molecules per molecule of glucose metabolized. Compare this to the glycerol 3-phosphate shuttle, which reduces FADH2 and donates electrons to the quinone pool in the electron transport chain, and is capable of generating only 2 ATPs per NADH generated in glycolysis (ultimately resulting in a net gain of 36 ATPs per glucose metabolized). (These ATP numbers are prechemiosmotic, and should be reduced in light of the work of Mitchell and many others. Each NADH produced only 2.5 ATPs, and each FADH2 produces only 1.5 ATPs. Hence, the ATPs per glucose should be reduced to 32 from 38 and 30 from 36).

Can someone please translate this into engrish?

[Yacoubb]

Glycolysis doesn't differ between organs, it's a biochemical process where the same thing always happens (and yes, 4 ATP produced but net is 2)

Okay, so that means 4 ATP molecules are produced, the net output is 2, and the remanining 2 ATP molecules are used for the transport of pyruvate molecules to the mitochondria for Kreb's Cycle and the Electron Transport Chain? Just clarifying.

[Stick]

Glycolysis doesn't differ between organs, it's a biochemical process where the same thing always happens (and yes, 4 ATP produced but net is 2)

Just to confirm, does that mean that the electron transport chain always produces 32 ATP molecules? There's so much conflicting information around. :S

[Yacoubb]

Just to confirm, does that mean that the electron transport chain always produces 32 ATP molecules? There's so much conflicting information around. :S

Stick, it can be 32 or 34. What we mentioned is that although 4 ATP molecules are produced in Glycolysis, there is a net output of 2 ATP molecules; so we only use 2 out of the 4 manufactured.

[Stick]

I'm really confused. :S

[Yacoubb]

I'm really confused. :S

Okay so look at it this way:

4 ATP molecules are produced in Glycolysis; however, there is a net output of only 2 of these ATP molecules that can be expended by living organisms for endergonic biochemical processes necessary to survival. The other two ATP molecules are sources of energy for the transport of the pyruvate from the cell's cytosol to the mistochondria through the mitochondrial membrane by active transport. There are then 2 ATP molecules/glucose molecule synthesised in Kreb's Citric Acid Cycle and then 32 or 34 ATP molecules/glucose molecule synthesised in Electron Transport Chain, depending on whether the cell has an ATP energy yield overall of 36 or 38 ATP molecules/glucose molecule.

[Scooby]

Glycolysis results in 4 ATP molecules being produced per glucose molecule. However, during the prepatory phase of glycolysis, 2 ATP molecules are consumed.

So we say glycolysis results in a net production of 2 ATP molecules per glucose molecule