Metabolism and Energy Extraction

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Questions and Answers

What is metabolism?

Metabolism is the sum of all anabolic and catabolic reactions taking place in the body.

What are anabolism and catabolism?

Anabolism is the process where smaller, simpler molecules are combined into larger more complex substances, while catabolism is the process by which larger complex substances are broken down into smaller simpler molecules, releasing energy.

What are metabolic pathways?

Metabolic pathways are linked series of chemical reactions occurring within living cells.

What are the six major types of reactions found in metabolic pathways?

<ol> <li>Ligation reactions, 2. The Formation/Removal of Carbon-Carbon Double Bonds, 3. Isomerization reactions, 4. Group transfer reactions, 5. Hydrolysis reactions, 6. Redox reaction.</li> </ol> Signup and view all the answers

Linear pathways start with a substrate and end with a product through a simple series of defined chemical modification steps, while a circular metabolic pathway is a series of biochemical reactions where the final product regenerates an initial ______.

substrate Signup and view all the answers

What is the basic unit derived from carbohydrates after digestion?

Monosaccharides (glucose) Signup and view all the answers

In glycolysis, what is the final product that glucose is converted into?

Two molecules of pyruvate Signup and view all the answers

How is energy produced in glycolysis?

The release of energy from the bond breaking in ATP. Signup and view all the answers

Complete the overall chemical reaction of glycolysis: 1 Glucose + 2 NAD+ + 2 ADP + 2 ______ = 2 pyruvate + 2 ATP + 2 NADH + 2 H+.

Pi Signup and view all the answers

What is one purpose of fermentation?

To replenish the supply of NAD+ for glycolysis. Signup and view all the answers

Which biomolecule class do glucose and maltose belong to?

Carbohydrates Signup and view all the answers

What is the unit to measure energy in food?

Calories Signup and view all the answers

What are the biomolecules that provide energy from food?

Carbohydrates and proteins. Signup and view all the answers

How does the breakdown of carbohydrates in the human body differ from burning fuel in a car?

The breakdown of carbohydrates is controlled and takes place slowly, while burning fuel is rapid and uncontrolled. Signup and view all the answers

At which step in the generation of ATP is ATP produced?

Step 1. Signup and view all the answers

What is the fate of lactic acid produced during anaerobic energy production in muscles?

Lactic acid is subsequently released into the bloodstream to be metabolized by the liver and kidneys. Signup and view all the answers

Study Notes

Metabolism

The sum of all chemical reactions that occur in living organisms
Essential for life, supporting functions such as growth, repair, and energy production

Anabolism and Catabolism

Anabolism: Constructive processes that build larger molecules from smaller ones, requiring energy; examples include protein synthesis and glycogen formation
Catabolism: Destructive processes that break down larger molecules into smaller ones, releasing energy; examples include digestion and cellular respiration

Metabolic Pathways

A series of interconnected biochemical reactions that occur in a specific sequence
Each step catalyzed by a specific enzyme, regulating the flow of metabolites

Types of Reactions in Metabolic Pathways

Dehydration reactions: Removal of water molecule, forming a new bond
Hydrolysis reactions: Addition of water molecule, breaking a bond
Redox reactions: Transfer of electrons (reduction-oxidation)
Phosphorylation reactions: Addition of a phosphate group
Decarboxylation reactions: Removal of a carboxyl group (CO₂)
Isomerization reactions: Rearrangement of atoms within a molecule

Circular Metabolic Pathway

The final product regenerates an initial substrate

Carbohydrate Digestion

The basic unit derived from carbohydrates after digestion is monosaccharide

Glycolysis

A metabolic pathway that breaks down glucose into pyruvate
The final product is pyruvate
Energy is produced through substrate-level phosphorylation, where ATP is directly synthesized by enzymes using energy from a substrate
Overall chemical reaction of glycolysis: 1 Glucose + 2 NAD+ + 2 ADP + 2 Pi = 2 pyruvate + 2 ATP + 2 NADH + 2 H+

Fermentation

One purpose is to regenerate NAD+ from NADH, allowing glycolysis to continue in the absence of oxygen.

Biomolecules and Energy

Glucose and maltose belong to the carbohydrate class of biomolecules
Energy in food is measured in Calories
Biomolecules that provide energy from food include carbohydrates, fats, and proteins

Carbohydrate Breakdown vs. Car Combustion

The breakdown of carbohydrates in the human body is a highly controlled and regulated process, generating energy in small, manageable steps.
Burning fuel in a car is a rapid and uncontrolled combustion reaction, releasing energy in a single, large burst.

ATP Production

ATP is produced at the substrate-level phosphorylation step in the generation of ATP.

Lactic Acid Fate

Lactic acid produced during anaerobic energy production in muscles can be converted back to pyruvate or used as fuel by other tissues.

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Description

This quiz covers the essentials of metabolism, including catabolic and anabolic processes, as well as energy extraction from carbohydrates, proteins, and lipids. Explore the various metabolic pathways and the chemical reactions involved in transforming food into energy. Test your understanding of how these processes sustain life.