Where Citric Acid Cycle Takes Place

In eukaryotes, the reactions of the citric acid cycle take place inside mitochondria, in contrast with those of glycolysis, which take place in the cytosol (Figure 17.1).

Where does citric cycle take place?

In eukaryotes, the citric acid cycle takes place in the matrix of the mitochondria, just like the conversion of pyruvate to acetyl CoAstart text, C, o, A, end text. In prokaryotes, these steps both take place in the cytoplasm.

Where does the citric acid cycle occur in the mitochondria?

Within the mitochondrion, the citric acid cycle occurs in the mitochondrial matrix, and oxidative metabolism occurs at the internal folded mitochondrial membranes (cristae).

Does the citric acid cycle take place in the stroma?

Explanation: The Krebs cycle takes place within the mitochondrial matrix of mitochondria. Glycolysis occurs in the cell’s cytosol. The stroma is part of plant chloroplasts, thus it is not the site of the Krebs cycle.

In what conditions does the process of citric acid cycle take place?

The citric acid cycle operates only under aerobic conditions because it requires a supply of NAD+ and FAD. The irreversible formation of acetyl CoA from pyruvate is an important regulatory point for the entry of glucose-derived pyruvate into the citric acid cycle.

Where does etc take place?

The electron transport chain activity takes place in the inner membrane and the space between the inner and outer membrane, called the intermembrane space.

What is TCA cycle and where does it occur?

This metabolic process occurs in most plants, animals, fungi, and many bacteria. In all organisms except bacteria the TCA cycle is carried out in the matrix of intracellular structures called mitochondria.

Where does glycolysis take place in plants?

Plant glycolysis occurs in the cytosol and plastids of green and non-green cells in which the requirements of energy and precursors may be completely different.

Is citric acid cycle anabolic or catabolic?

Explanation: The citric acid cycle is amphibolic—that is, both anabolic and catabolic. Anabolism occurs when the citric acid cycle generates reduced factors, such as NADH and FADH2. Catabolism occurs when the citric acid cycle oxidizes the two carbon atoms of acetyl CoA to carbon dioxide (CO2).

What is the role of the citric acid cycle?

The citric acid cycle, also known as the Krebs cycle or the tricarboxylic acid cycle, is at the center of cellular metabolism, playing a starring role in both the process of energy production and biosynthesis. It finishes the sugar-breaking job started in glycolysis and fuels the production of ATP in the process.

Where does oxidative phosphorylation take place?

Oxidative phosphorylation takes place in the inner mitochondrial membrane, in contrast with most of the reactions of the citric acid cycle and fatty acid oxidation, which take place in the matrix.

What occurs in the first step of the citric acid cycle?

The first reaction of the citric acid cycle is catalyzed by the enzyme citrate synthase. In this step, oxaloacetate is joined with acetyl-CoA to form citric acid. Once the two molecules are joined, a water molecule attacks the acetyl leading to the release of coenzyme A from the complex.

Where does the ETC take place in photosynthesis?

In photosynthetic eukaryotes, the electron transport chain is found on the thylakoid membrane. Here, light energy drives the reduction of components of the electron transport chain and therefore causes subsequent synthesis of ATP.

Where does cellular respiration take place?

While most aerobic respiration (with oxygen) takes place in the cell’s mitochondria, and anaerobic respiration (without oxygen) takes place within the cell’s cytoplasm.

Where does the ETC take place in prokaryotic cells?

The only membrane in prokaryotes is the cellular membrane, that is where the ETC is located.

Where do the TCA reactions take place?

In eukaryotes, the reactions of the citric acid cycle take place inside mitochondria, in contrast with those of glycolysis, which take place in the cytosol (Figure 17.1).

Where do the protons used to drive Chemiosmosis during photosynthesis come from?

The photons in sunlight are received by the antenna complex of Photosystem II, which excites electrons to a higher energy level. These electrons travel down an electron transport chain, causing protons to be actively pumped across the thylakoid membrane into the thylakoid lumen.

Where does acetyl CoA formation take place?

Acetyl-CoA Formation. Acetyl-CoA formation occurs inside or outside the cell mitochondria. As a metabolite (a substance necessary for metabolism), acetyl-CoA must be freely available. It can be produced via the catabolism (breakdown) of carbohydrates (glucose) and lipids (fatty acids).

Does citric acid cycle occur in plant cells?

The citric acid cycle takes place in the mitochondria in plants.

Where does pyruvate processing occur?

The mitochondrion has a double membrane, and the space inside the inner membrane is called the matrix. So pyruvate processing and the citric acid cycle take place inside the mitochondrial matrix.

Where does gluconeogenesis occur?

The major site of gluconeogenesis is the liver, with a small amount also taking place in the kidney. Little gluconeogenesis takes place in the brain, skeletal muscle, or heart muscle.

Why is citric acid cycle called amphibolic pathway?

Because the citric acid cycle functions in both catabolism (Figure 11.1) and anabolism (Figure 11.2), we call it an amphibolic pathway. The citric acid cycle plays a pivotal role in cellular respiration, has multiple interconnections with other pathways, and provides for interconversions of numerous metabolites.

Why is citric acid cycle the central pathway in metabolism?

Due to the many functions of the citric acid cycle is also considered to be the “central hub of metabolism”. This is because, as most of the absorbed nutrients, the fuel molecules are oxidized ultimately within the Krebs Cycke and its intermediates are used for various biosynthetic pathways.

Where in the cell do the citric acid cycle and electron transport chain take place?

Like the conversion of pyruvate to acetyl CoA, the citric acid cycle in eukaryotic cells takes place in the matrix of the mitochondria. Unlike glycolysis, the citric acid cycle is a closed loop: The last part of the pathway regenerates the compound used in the first step.

Where is citrate produced?

Citrate is produced in the Krebs cycle from oxaloacetate and acetyl-CoA by citrate synthase (CS). It can be exported from the mitochondria through citrate carrier (CIC).

Where are the protons pumped to during Chemiosmosis?

Chemiosmosis involves the pumping of protons through special channels in the membranes of mitochondria from the inner to the outer compartment.

Which type of phosphorylation takes place in photosynthesis?

In the process of photosynthesis, the phosphorylation of ADP to form ATP using the energy of sunlight is called photophosphorylation. Cyclic photophosphorylation occurs in both aerobic and anaerobic conditions.

Where does the electron transport chain take place in the mitochondria?

The electron transport chain is a series of proteins and organic molecules found in the inner membrane of the mitochondria.