Ch.18 Metabolic Pathways and ATP Production

Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 14th Edition

Timberlake14th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9781292472249Not the one you use?Change textbook

Timberlake 14th Edition

Ch.18 Metabolic Pathways and ATP Production

Problem 27a

Chapter 18, Problem 27a

How many ATP or NADH are produced (or required) in each of the following steps in glycolysis?
a. glucose to glucose-6-phosphate

Verified step by step guidance

Step 1: Understand the context of glycolysis. Glycolysis is a metabolic pathway that breaks down glucose into pyruvate, producing ATP and NADH in the process. It consists of 10 steps, each catalyzed by a specific enzyme.

Step 2: Identify the specific step in question. The conversion of glucose to glucose-6-phosphate is the first step of glycolysis, catalyzed by the enzyme hexokinase (or glucokinase in the liver).

Step 3: Recognize the energy requirements of this step. This step is an energy-investment phase where ATP is consumed to phosphorylate glucose, forming glucose-6-phosphate. The reaction can be represented as:

glucose + {ATP}_{1 → {glucose}_{6} phosphate + {ADP}_{1}}

Step 4: Note that no NADH is involved in this step. NADH is produced later in glycolysis during the oxidation of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate.

Step 5: Conclude that this step requires the input of 1 ATP molecule and does not produce any ATP or NADH. This is part of the energy investment phase of glycolysis.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Glycolysis

Glycolysis is a metabolic pathway that converts glucose into pyruvate, producing energy in the form of ATP and NADH. It occurs in the cytoplasm of cells and consists of ten enzymatic reactions, divided into two phases: the energy investment phase and the energy payoff phase. Understanding glycolysis is essential for analyzing energy production and consumption in cellular respiration.

ATP Production

Adenosine triphosphate (ATP) is the primary energy currency of the cell, generated during glycolysis through substrate-level phosphorylation. In the conversion of glucose to glucose-6-phosphate, one ATP molecule is consumed, highlighting the energy investment required to initiate glycolysis. This step is crucial for understanding the overall energy balance in the glycolytic pathway.

NADH Production

Nicotinamide adenine dinucleotide (NADH) is a coenzyme that plays a vital role in cellular respiration by acting as an electron carrier. While the conversion of glucose to glucose-6-phosphate does not produce NADH, subsequent steps in glycolysis do generate it. Recognizing the role of NADH is important for understanding how energy is transferred and utilized in metabolic processes.

How many ATP or NADH are produced (or required) in each of the following steps in glycolysis?a. glucose to glucose-6-phosphate