2.3 Chemical Reactions
3 min read•june 18, 2024
Energy is the driving force behind all biological processes. From the food we eat to the air we breathe, chemical reactions power our bodies. These reactions involve the transfer and transformation of energy, allowing us to move, think, and live.
Chemical reactions in our bodies are carefully orchestrated processes. They involve breaking down complex molecules for energy, building new structures, and maintaining balance. Understanding these reactions helps us grasp how our bodies function and adapt to changing conditions.
Energy and Chemical Reactions
Kinetic vs potential energy
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- involves the energy of motion possessed by moving objects, particles, atoms, and molecules
- represents stored energy that is available for use but not currently being used, including stored in bonds between atoms
- release energy, often in the form of heat, with products having less potential energy than reactants, are spontaneous and favorable under all conditions (combustion, cell respiration, reactions)
- absorb energy from the surroundings, with products having more potential energy than reactants, are non-spontaneous and require an input of energy to proceed (, , )
- occurs when the forward and reverse reaction rates are equal, resulting in no net change in and concentrations
Energy forms for body functions
- Chemical energy involves potential energy stored in chemical bonds, released during exergonic reactions and absorbed during endergonic reactions (ATP, , fats)
- encompasses the of moving objects or particles, including energy of muscle contraction, blood flow, and joint movement
- represents the kinetic energy of moving charged particles (electrons or ions), essential for nerve impulse transmission, muscle contraction, and heart function
- (heat) refers to the kinetic energy of random motion of atoms and molecules, generated as a byproduct of many metabolic reactions, maintains body temperature and drives chemical reactions
Chemical Reactions in Biological Systems
Types of biological chemical reactions
- Synthesis (anabolic) reactions involve smaller molecules combining to form larger, more complex molecules, require an input of energy (endergonic) (protein synthesis, synthesis, lipid synthesis)
- Decomposition (catabolic) reactions break down larger molecules into smaller, simpler molecules, release energy (exergonic) (digestion of nutrients, breakdown, of fatty acids)
- involve atoms or functional groups being exchanged between molecules, may be exergonic or endergonic ( reactions, reactions)
- involve the transfer of electrons between molecules, playing a crucial role in energy metabolism and cellular respiration
Factors in chemical reaction speed
- Temperature: Higher temperatures increase the kinetic energy of molecules, leading to more frequent collisions and faster reactions; have optimal temperature ranges; extreme temperatures can denature enzymes
- of reactants: Higher concentrations of reactants increase the likelihood of collisions, speeding up the ; applies to ###-Substrate_Complexes_0### in biological systems
- Presence of (enzymes): Lower the required for a reaction to occur, speed up reactions without being consumed in the process, highly specific to their substrates and reactions
- : Changes in pH can alter the structure and function of enzymes; each enzyme has an optimal pH range; deviations can slow down or stop enzyme-catalyzed reactions
- Surface area: Larger surface area of reactants increases the frequency of collisions, speeding up the reaction rate; relevant in digestion, where mechanical and chemical breakdown of food increases surface area for enzymatic reactions
Reaction Kinetics
- Reaction rate refers to the speed at which reactants are converted into products, influenced by factors such as temperature, concentration, and catalysts
- is the minimum energy required for a reaction to occur, often lowered by enzymes in biological systems
- The states that the rate of a chemical reaction is proportional to the product of the concentrations of the reactants
Key Terms to Review (46)
Activation energy: Activation energy is the minimum amount of energy required to initiate a chemical reaction. It serves as an energy barrier that reactants must overcome before transforming into products.
Activation Energy: Activation energy is the minimum amount of energy required to initiate a chemical reaction. It is the energy barrier that must be overcome for the reactants to form the products of the reaction. Activation energy is a crucial concept in understanding the kinetics and thermodynamics of chemical processes.
Anabolic Reactions: Anabolic reactions are a type of metabolic process in which smaller, simpler molecules are combined to form larger, more complex molecules. This process requires an input of energy and is essential for the growth, repair, and maintenance of tissues within the body.
ATP (Adenosine Triphosphate): ATP, or adenosine triphosphate, is the primary energy currency of the cell. It is a high-energy molecule that stores and transports the chemical energy needed to power a wide variety of cellular processes, from muscle contraction to protein synthesis. ATP is central to the functions of human life, chemical bonds, chemical reactions, organic compounds, cellular organelles, protein synthesis, muscle contraction, respiration, metabolism, and fluid balance.
ATP synthase: ATP synthase is an enzyme complex embedded in the mitochondrial membrane that facilitates the synthesis of ATP (adenosine triphosphate), the primary energy carrier in cells, from ADP (adenosine diphosphate) and inorganic phosphate during the process of oxidative phosphorylation within carbohydrate metabolism. It acts as a molecular generator, converting an electrochemical gradient into energy stored in the form of ATP.
ATP Synthesis: ATP (Adenosine Triphosphate) synthesis is the process by which cells produce the universal energy currency of the cell, ATP, from simpler molecules. This process is a crucial component of cellular respiration and is closely linked to the concept of chemical reactions.
Beta-Oxidation: Beta-oxidation is the process by which fatty acids are broken down in the mitochondria of cells to generate acetyl-CoA, which can then enter the citric acid cycle to produce ATP, the primary energy currency of the cell. This catabolic pathway is a crucial component of lipid metabolism and overall energy production within the human body.
Catalyst: A catalyst is a substance that increases the rate of a chemical reaction without being consumed or altered in the process. In anatomy and physiology, enzymes serve as biological catalysts facilitating vital biochemical reactions within the body.
Catalysts: Catalysts are substances that increase the rate of a chemical reaction without being consumed or altered themselves. They work by providing an alternative pathway with a lower activation energy, allowing the reaction to proceed more quickly and efficiently.
Chemical Energy: Chemical energy is the potential energy stored within the chemical bonds of molecules. It is the energy released or absorbed during chemical reactions as bonds are formed or broken, enabling the transformation of matter and the release of usable energy for various biological and physical processes.
Chemical Equilibrium: Chemical equilibrium is a state of balance in a chemical system where the forward and reverse reactions occur at equal rates, resulting in no net change in the concentrations of the reactants and products over time. This dynamic balance is a fundamental concept in understanding chemical reactions and their behavior.
Concentration: Concentration in the context of chemical reactions refers to the amount of a substance (solute) present in a certain volume of solution. It significantly influences the rate and direction of chemical reactions in the body.
Decomposition reaction: A decomposition reaction in the context of Anatomy and Physiology is a chemical reaction where a compound breaks down into two or more simpler substances. It plays a crucial role in the body's metabolic processes, breaking down complex molecules to provide energy and building blocks for growth.
Decomposition Reactions: Decomposition reactions are a type of chemical reaction in which a single reactant breaks down into two or more simpler products. These reactions involve the breaking of chemical bonds within the reactant molecule, leading to the formation of new, less complex substances.
Electrical Energy: Electrical energy is the energy associated with the movement of electric charge, such as electrons, through a conductor. It is the form of energy that powers various electrical devices and systems, enabling the conversion of electrical energy into other forms of energy like heat, light, or mechanical energy.
Endergonic Reactions: Endergonic reactions are chemical reactions that require an input of energy to proceed. These types of reactions are the opposite of exergonic reactions, which release energy. Endergonic reactions are essential for maintaining the complex structures and functions of living organisms.
Enzyme: Enzymes are proteins that act as biological catalysts, speeding up chemical reactions in the body without being consumed or altered in the process. They play a crucial role in various bodily functions, including digestion and metabolism.
Enzyme-Substrate Complexes: Enzyme-substrate complexes are temporary molecular structures formed when an enzyme binds to its specific substrate molecule(s) during a chemical reaction. This binding interaction is a crucial step in the catalysis of biochemical reactions within living organisms.
Enzymes: Enzymes are biological catalysts that accelerate the rate of chemical reactions in the body without being consumed or altered themselves. They play a crucial role in the structural organization of the human body, chemical reactions, organic compounds essential to human functioning, chemical digestion and absorption, and metabolic reactions.
Exchange reaction: In an exchange reaction, parts of the reacting molecules are shuffled around to produce new products. It is a type of chemical reaction where bonds are broken and new ones are formed, resulting in different compounds.
Exchange Reactions: Exchange reactions are a type of chemical reaction where atoms or groups of atoms are exchanged between two or more reactants, resulting in the formation of new products. These reactions are fundamental to many chemical processes in the body and the environment.
Exergonic Reactions: Exergonic reactions are chemical reactions in which energy is released to the surroundings, typically in the form of heat. These reactions occur spontaneously and proceed with a decrease in free energy, making them favorable and driving forces for many biological processes.
Glucose: Glucose is a simple sugar that serves as the primary source of energy for the body's cells. It is a crucial component in various metabolic processes and is essential for human life and functioning.
Glucose-6-phosphate: Glucose-6-phosphate is a glucose sugar molecule that has been phosphorylated on the sixth carbon. It plays a crucial role in the metabolic pathways of glycolysis and gluconeogenesis, acting as an intermediary molecule that helps in the storage and use of energy within cells.
Glycogen: Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals and fungi. It is the primary storage form of glucose in the body, predominantly found in the liver and muscle tissues.
Glycogen: Glycogen is a complex carbohydrate that serves as the primary storage form of glucose in the human body. It is primarily found in the liver and skeletal muscles, where it can be rapidly broken down to provide energy when needed.
Hydrolysis: Hydrolysis is a chemical reaction in which a molecule is cleaved into two or more smaller molecules by the addition of a water molecule. This process involves the breaking of chemical bonds through the incorporation of the hydrogen (H+) and hydroxide (OH-) ions from water.
Inactive proenzymes: Inactive proenzymes are precursor molecules that require a chemical transformation to become active enzymes, which then catalyze specific biochemical reactions in the body. This transformation often involves the removal of certain segments from the proenzyme molecule.
Kinetic energy: Kinetic energy is the energy an object possesses due to its motion. In the context of chemical reactions, it's related to the movement of atoms and molecules that facilitates chemical bonds to form or break.
Kinetic Energy: Kinetic energy is the energy of motion possessed by an object. It is the energy that an object has by virtue of being in motion and is directly proportional to the mass of the object and the square of its velocity.
Law of Mass Action: The law of mass action is a fundamental principle in chemistry that describes the relationship between the concentrations of reactants and the rate of a chemical reaction. It states that the rate of a chemical reaction is proportional to the product of the molar concentrations of the reactants, each raised to a power equal to the stoichiometric coefficient of that reactant in the balanced chemical equation.
Mechanical Energy: Mechanical energy is the sum of the potential energy and kinetic energy possessed by an object. It represents the capacity to do work or cause change through physical motion or position. This term is particularly relevant in the context of chemical reactions, as the transfer and transformation of mechanical energy can drive and influence these reactions.
Oxidative phosphorylation: Oxidative phosphorylation is a metabolic process by which cells generate ATP, the primary energy currency, through the transfer of electrons from nutrient molecules to molecular oxygen in mitochondria. This process involves a chain of protein complexes and electron carriers within the inner mitochondrial membrane, culminating in the production of water and ATP.
PH: pH, or potential of hydrogen, is a measure of the acidity or basicity of a solution. It is a scale that ranges from 0 to 14, with 7 being neutral, values less than 7 being acidic, and values greater than 7 being basic or alkaline. The pH of a solution is determined by the concentration of hydrogen ions (H+) present.
Phosphorylation: Phosphorylation is a fundamental biochemical process in which a phosphate group (PO4) is added to a molecule, typically a protein, by an enzyme. This process is crucial for the regulation and activation of various cellular functions and signaling pathways.
Photosynthesis: Photosynthesis is the process by which plants and some other organisms use the energy from sunlight to convert carbon dioxide and water into glucose and oxygen. This chemical reaction is essential for the survival of most life on Earth, as it provides the primary source of energy and organic compounds for the biosphere.
Potential Energy: Potential energy is the stored energy that an object possesses due to its position or state. It is the energy that an object has the potential to release or convert into other forms of energy, such as kinetic energy, when the object is moved or undergoes a change in its physical or chemical state.
Product: In the context of Anatomy and Physiology, especially within the chapter on The Chemical Level of Organization, a product is a substance that results from a chemical reaction. It is what is formed when reactants undergo a chemical change during biochemical processes in the body.
Reactant: In the context of Anatomy and Physiology, a reactant is a substance that takes part in and undergoes change during a chemical reaction within the body. These changes are fundamental for processes such as metabolism, respiration, and cellular repair.
Reaction Rate: Reaction rate is the measure of the speed at which a chemical reaction takes place, quantifying the change in the concentration of reactants or products over time. It is a fundamental concept in the study of chemical reactions and their dynamics.
Redox Reactions: Redox (reduction-oxidation) reactions are a fundamental type of chemical reaction in which the oxidation state of atoms is changed. These reactions involve the transfer of electrons between chemical species, with one substance losing electrons (oxidation) and another gaining electrons (reduction).
Synthesis reaction: A synthesis reaction in anatomy and physiology is a chemical process where two or more reactants combine to form a more complex product. This type of reaction is fundamental in the body for building macromolecules from simpler substances.
Synthesis Reactions: Synthesis reactions, also known as combination reactions, are a type of chemical reaction in which two or more reactants combine to form a single product. These reactions result in the creation of a new, more complex molecule from simpler starting materials.
Thermal Energy: Thermal energy refers to the total kinetic energy of the atoms or molecules within a substance due to their random motion. It is the energy associated with the heat of a system and is a measure of the vibrational and translational motion of the particles that make up the substance.
Transamination: Transamination is a biochemical process where an amino group from one amino acid is transferred to a keto acid, forming a new amino acid. This process is crucial for the synthesis of non-essential amino acids within the body.
Transamination: Transamination is a metabolic process in which an amino group is transferred from one molecule to another, typically involving the conversion of an amino acid to a different amino acid or a keto acid. This process is a crucial part of protein metabolism and the breakdown and synthesis of amino acids within the body.