Metabolism Lecture Notes

Flashcards about metabolism for exam review

In general, in glycolysis, what energy transfers occur?

Energy is transferred from glucose to ADP to make ATP and from glucose to NAD to make NADH.

Which molecule has less stored energy, pyruvate or acetyl CoA?

Acetyl CoA

Why does pyruvate have more stored energy than acetyl CoA?

Pyruvate has more electrons to donate to NAD to make NADH.

What is the term for the reaction that occurs when one of the carbons from pyruvate is lost as CO2?

Decarboxylation.

Where does the oxygen in the CO2 come from in decarboxylation reactions?

The oxygen in the CO2 comes from things like water or the glucose itself, not from the O2 you breathe.

In prokaryotic cells, where does the citric acid cycle take place?

Cytoplasm.

In eukaryotic cells, where does the citric acid cycle take place?

Mitochondria.

What is the overall purpose of the citric acid cycle?

To remove as many electrons as possible from acetyl CoA.

At the end of the citric acid cycle, what is the only thing remaining from acetyl CoA?

Carbon dioxide.

How many decarboxylation reactions are there in the citric acid cycle?

Two.

Where do the electron carriers (NADH and FADH2) go after the citric acid cycle?

The electron transport chain.

Why does acetyl CoA have more stored energy than NADH?

Acetyl CoA has enough electrons to turn six NAD into NADH.

What kind of reaction is it when going from ADP to ATP?

Synthesis.

How much ATP is made in glycolysis and the citric acid cycle?

Glycolysis nets two ATP, and the citric acid cycle generates two ATP, for a total of four ATP.

In total, how many NADH and FADH2 molecules are made in glycolysis, pyruvate oxidation, and the citric acid cycle?

10 NADH and 2 FADH2.

What are the two components of oxidative phosphorylation?

The electron transport chain and chemiosmosis.

What is the purpose of the electron transport chain?

To make a proton gradient.

What is the purpose of chemiosmosis?

To use the energy stored in the proton gradient to make ATP.

Why are there so many steps in cellular respiration?

Both occur in slow, incremental releases of energy to be more efficient, losing less as waste product or heat.

In a prokaryotic cell, where does oxidative phosphorylation take place?

The intercellular fluid (cytoplasm) and the cell membrane.

In eukaryotic cells, where does oxidative phosphorylation take place?

The mitochondria.

What does a mitochondria look like?

The jelly bean is made up of two layers of phospholipid bilayers with an outer membrane and an inner membrane with all the dips and valleys in it.

If I'm moving something from low concentration to high concentration, is that active or passive transport?

Active.

What happens to the electron at the end of the electron transport chain?

Combine with oxygen (O2) to make water.

What is oxygen called in the electron transport chain?

The final electron acceptor.

What is the final electron acceptor in the electron transport chain?

Oxygen (O2).

What is created when you combine the leftover electrons with oxygen at the end of the electron transport chain?

Water (H2O).

Why is continually recycling ATP important?

Because each cell, even the most active, only has enough ATP to power about eight seconds of work.

Can you describe the differences between concentration gradient gradient and electrical gradient established by this cycle

That will be the same amount of energy for both gradients but what determines a proton pump is an electrical gradient and that is from the proton difference