Metabolism Part 1 Overview

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In which type of reactions is NADPH primarily used?

Anabolic reactions

What is the overall standard Gibbs free energy change for the breakdown of glucose in cellular respiration?

-2872.2 kJ

Where does the oxidation half-reaction of glucose occur?

Cell cytoplasm

How are electrons carried from one half-reaction to the other in glucose breakdown?

Via coenzymes NADH and FADH2 Signup and view all the answers

In which cellular location does the reduction half-reaction of glucose breakdown occur?

Cytoplasmic membrane Signup and view all the answers

What is the definition of metabolism?

Metabolism is the sum of all biochemical reactions occurring in a cell, including both catabolic and anabolic reactions. Signup and view all the answers

Describe the difference between catabolism and anabolism.

Catabolism refers to energy generating reactions that occur spontaneously, while anabolism involves energy-requiring cell building reactions that are not spontaneous. Signup and view all the answers

How are anabolic reactions made possible?

Anabolic reactions (endergonic) are made possible by using the energy produced by catabolic reactions (exergonic). Signup and view all the answers

Explain the role of ATP in cells.

Energy is distributed through cells in the form of ATP, which serves as an energy storage molecule. Signup and view all the answers

What is the function of a catalyst in a chemical reaction?

A catalyst speeds up a reaction without being permanently altered itself. Signup and view all the answers

What are biological catalysts called?

Biological catalysts are called enzymes. Signup and view all the answers

What is the role of an externally provided electron acceptor in respiration?

To oxidize pyruvate to CO2 Signup and view all the answers

What is the key role of phosphofructokinase in the glycolysis pathway?

To regulate glycolysis by being a key enzyme Signup and view all the answers

What inhibits phosphofructokinase in glycolysis?

ATP Signup and view all the answers

Which glycolysis pathway is commonly used by bacteria, archaea, and eukaryotes?

EMP pathway Signup and view all the answers

What is the alternative pathway to glycolysis that uses sugar acids like 6-phosphogluconate?

Entner-Doudoroff (ED) pathway Signup and view all the answers

What is the preparatory stage of glycolysis known as?

Embden-Meyerhof Pathway Signup and view all the answers

What is the purpose of phosphorylation in the context of ATP generation?

To add a phosphate group to ADP, forming ATP, as a way to store energy. Signup and view all the answers

Describe substrate-level phosphorylation and provide an example.

It is driven by breaking a high-energy bond in a substrate to directly add a phosphate group to ADP, forming ATP. An example is the conversion of R~P to ATP. Signup and view all the answers

How is ATP generated in oxidative phosphorylation?

NADH and FADH carry electrons to the electron transport chain, leading to the production of ATP via chemiosmosis. Signup and view all the answers

What is the role of light energy in photophosphorylation?

Light energy is used to generate ATP and NADH in photosynthetic cells. Signup and view all the answers

Why does ATP often form a complex with Mg^2+?

The presence of Mg^2+ stabilizes the structure of ATP by neutralizing its charge and coordinating with the oxygen atoms. Signup and view all the answers

What is the significance of Mg^2+ in facilitating ATP's role as a universal energy carrier?

Mg^2+ coordination with ATP helps in stabilizing its structure, making it more efficient as an energy carrier in biological processes. Signup and view all the answers

What is the main purpose of the Pentose Phosphate Shunt (PPS)?

To produce building blocks and reducing power for anabolic reactions. Signup and view all the answers

How does the Krebs Cycle (TCA cycle) preparatory stage regulate the flow of carbon into the cycle?

The pyruvate dehydrogenase complex (PDC) controls the entry of carbon into the Krebs cycle. Signup and view all the answers

What are the main functions of PDH in the Krebs Cycle preparatory stage?

E1 removes CO2 from pyruvate and attaches acetyl group, E2 transfers acetyl group to lipoamide, E3 uses stored electrons to reduce NAD+. Signup and view all the answers

How many ATP molecules (net) are produced during glycolysis per molecule of glucose transformed?

2 ATP Signup and view all the answers

What is the fate of glucose during glycolysis?

Glucose is broken down into two 3-carbon chains that are partially oxidized to form pyruvate molecules. Signup and view all the answers

How does the Pentose Phosphate Shunt (PPS) pathway differ from the Embden-Meyerhof Pathway (EMP)?

The PPS is found in a wider variety of bacteria and archaea, indicating it may be evolutionarily older. Signup and view all the answers