Which of these is not true of the citric acid cycle? a. The...

Name: Problem 10, Chapter 8: Biology
Uploaded: 2019-07-09T03:05:55-08:00
Duration: 4 min 51 s
Channel: Nalvi Duro
Description: Which of these is not true of the citric acid cycle? a. The citric acid cycle includes the prep reaction. b. The citric acid cycle produces ATP by substrate-level ATP synthesis. c. The citric acid cycle occurs in the mitochondria. d. The citric acid cycle produces two ATP per glucose molecule.

Which of these is not true of the citric acid cycle? a. The citric acid cycle includes the prep reaction. b. The citric acid cycle produces ATP by substrate-level ATP synthesis. c. The citric acid cycle occurs in the mitochondria. d. The citric acid cycle produces two ATP per glucose molecule.

Which of these is not true of the citric acid cycle?
a. The citric acid cycle includes the prep reaction.
b. The citric acid cycle produces ATP by substrate-level ATP synthesis.
c. The citric acid cycle occurs in the mitochondria.
d. The citric acid cycle produces two ATP per glucose molecule.

Key Concepts

Citric Acid Cycle

The citric acid cycle, also known as the Krebs cycle or TCA cycle, is a central component of cellular respiration. It oxidizes acetyl-CoA to produce energy-rich electron carriers (NADH and FADH2) and a modest amount of ATP (or GTP) via substrate-level phosphorylation, while also generating key intermediates for biosynthetic pathways.

Preparation Reaction

The preparation reaction, sometimes referred to as the link reaction or pyruvate decarboxylation, is the process that converts pyruvate from glycolysis into acetyl-CoA before entry into the citric acid cycle. It is a distinct step that occurs separately from the cycle itself.

Substrate-Level Phosphorylation

Substrate-level phosphorylation is a direct method of ATP synthesis that involves the transfer of a phosphate group from a phosphorylated intermediate directly to ADP, forming ATP. In the citric acid cycle, this mechanism is responsible for a small amount of ATP production, contrasting with the larger yield from oxidative phosphorylation.

Mitochondrial Localization

In eukaryotic cells, the citric acid cycle takes place in the mitochondria, a specialized organelle that houses key metabolic pathways. The mitochondrial environment is essential for the efficient functioning of the cycle and subsequent energy production through oxidative phosphorylation.

Transcript

00:01 Okay, so we are trying to find the incorrect statement concerning the citric acid cycle.

00:11 So a quick overview of what goes into the citric acid cycle.

00:16 So first you start with glucose and glucose undergoes glycolysis to produce two pyruvate molecules.

00:31 This is glycolysis.

00:35 And then pyruvate combines with co -enzyme a to produce acetylcoa and two carbon dioxide.

00:46 Acetylcoa then goes over here.

00:53 And we are told here in step one that the citric acid cycle begins when the acetyl -2, the acetyl group carried by coenzyme a combines with a c4 molecule to form citrate.

01:10 So this step right here is called preparatory step to form acetyl co -a, which then goes into the citric acid cycle.

01:26 Okay.

01:27 Now, you can see right away that choice a is not true.

01:36 Of the citric acid cycle because we just determined that the citric acid cycle begins with c2 acetyl group carried by coenzyme a to combine with the c4 molecule to form citrate and the preparatory step is a separate step from that.

02:02 Now choice b is citric acid cycle produces atp by substrate level atp synthesis.

02:10 This is true and by atp substrate level synthesis, this means that the phosphate that is coming to join this atp is coming from another molecule.

02:26 It is coming from another molecule.

02:38 And that is different than in the electron transport chain because in the electron transport chain, you have a proton gradient that is driving atp synthetase...

Please give Ace some feedback