Ch 2 Chemistry - Chemistry of Life

Flashcards covering key vocabulary from Chapter 2 Chemistry, focusing on the chemistry of life, including atoms, molecules, chemical bonds, water properties, pH, chemical reactions, and the four major biomolecules (carbohydrates, lipids, proteins, and nucleic acids).

Atom

The simplest unit of matter, made of subatomic particles like protons, neutrons, and electrons.

Element

The simplest form of matter to have unique chemical properties, identified by its atomic number.

Atomic Number

The number of protons in an atom's nucleus, which identifies the element.

Nucleus (of an atom)

The central part of an atom, containing protons and neutrons.

AMU (Atomic Mass Unit)

The unit of mass for protons and neutrons.

Isotope

Atoms of the same element with the same number of protons but different numbers of neutrons, resulting in different atomic masses.

Radioisotope

An unstable isotope that decays over time, releasing radiation.

Half-life

The time required for half of the radioactive atoms in a sample to decay.

Valence Electrons

Electrons in the outermost energy shell of an atom, which determine its chemical binding properties.

Ion

A charged atom or molecule resulting from the gain or loss of one or more electrons.

Cation

A positively charged ion, formed when an atom loses electrons.

Anion

A negatively charged ion, formed when an atom gains electrons.

Electrolyte

Substances that ionize in water and whose solutions can conduct electricity, crucial for muscle and nerve cell function.

Molecule

A chemical particle consisting of two or more atoms united by chemical bonds.

Compound

A molecule composed of two or more different elements.

Molecular Weight

The sum of the atomic weights of all atoms in a molecule.

Isomer

Molecules with the same chemical formula but different structural arrangements, affecting their chemical interactions.

Covalent bond

A strong chemical bond formed when atoms share one or more pairs of electrons.

Nonpolar Covalent Bond

A covalent bond where electrons are shared equally between atoms due to similar electronegativities.

Polar Covalent Bond

A covalent bond where electrons are shared unequally between atoms, resulting in partial positive and negative charges on the atoms.

Ionic Bond

An attraction between oppositely charged ions, typically weaker than covalent bonds and dissociating in water.

Hydrogen Bond

A weak attraction between a slightly positive hydrogen atom and a slightly negative oxygen or nitrogen atom, important for water properties and macromolecule stability.

Van der Waals forces

Weak, brief attractions between neutral atoms due to fleeting shifts in electron distribution, important for lipid interactions.

Polar Molecule

A molecule with an uneven distribution of charge due to polar covalent bonds, like water.

Hydrocarbon

A nonpolar molecule composed only of hydrogen and carbon atoms, which does not interact with water.

Solvency

The ability of a substance, such as water (the universal solvent), to dissolve other polar chemicals.

Hydrophilic

Describing substances that dissolve readily in water, typically polar or charged.

Hydrophobic

Describing nonpolar substances that do not dissolve in water, such as lipids.

Cohesion (of water)

The tendency of water molecules to stick to each other due to hydrogen bonds, leading to properties like surface tension.

Adhesion (of water)

The attraction of water molecules to other polar particles or surfaces.

Thermal Stability (of water)

Water's high heat capacity, allowing it to absorb and release significant energy without major temperature changes, important for cooling through sweat.

Solution

A homogeneous mixture where a solute is dissolved in a solvent, typically transparent, stable, and able to pass through membranes.

Solvent

The more abundant substance in a solution, which dissolves the solute (e.g., water).

Solute

The substance that is dissolved in a solvent to form a solution.

Colloid

A mixture with particles between 1 and 100 nm, which scatter light, cannot pass through membranes, and remain mixed on standing (e.g., milk proteins).

Suspension

A mixture with particles larger than 100 nm, which are cloudy to opaque, cannot penetrate membranes, and separate on standing (e.g., cells in blood).

Emulsion

A suspension of one liquid in another liquid (e.g., oil and vinegar).

pH

A measure of the hydrogen ion concentration in a solution, expressed as the negative logarithm (inverse and exponential scale).

Acid

A proton donor, releasing hydrogen ions (H+) into a solution, resulting in a pH below 7.

Base (Alkaline)

A proton acceptor, removing hydrogen ions (H+) from a solution, resulting in a pH above 7.

Buffers

Chemical systems that resist changes in pH by accepting or releasing hydrogen ions, helping to maintain homeostasis.

Molarity

A measure of solution concentration indicating the number of moles of solute per liter of solution, useful for quantifying particle numbers in physiology.

Energy

The capacity to do work, such as moving something or breaking/building chemical bonds, often stored and released via ATP.

Chemical Reaction

A process involving the formation or breaking of covalent or ionic bonds, described by a chemical equation.

Reactants

The starting substances in a chemical reaction.

Products

The substances formed at the end of a chemical reaction.

Decomposition Reaction

A chemical reaction that breaks larger molecules into smaller ones, often releasing energy (e.g., hydrolysis).

Hydrolysis

A decomposition reaction in which water breaks a covalent bond, with H+ and OH- added to the resulting pieces.

Synthesis Reaction

A chemical reaction that joins smaller molecules into larger ones, requiring energy (e.g., dehydration synthesis).

Dehydration Synthesis

A synthesis reaction in which water is removed to form a covalent bond, joining two molecules.

Oxidation

The loss of electrons by an atom or molecule, resulting in less energy in the oxidized substance.

Reduction

The gain of electrons by an atom or molecule, resulting in more energy in the reduced substance.

Organic Compound

A compound of carbon, characterized by stable nonpolar covalent bonds and the ability to form carbon backbones and bind to many other elements.

Functional Group

A specific cluster of atoms attached to the carbon backbone of organic molecules, imparting characteristic chemical properties (e.g., Hydroxyl, Methyl, Carboxyl, Amine, Phosphate).

Monomer

A small subunit molecule that can be joined to others via covalent bonds (dehydration synthesis) to form a larger polymer.

Polymer

A large molecule composed of repeating monomer subunits, which can be broken down via hydrolysis.

Carbohydrate

A biomolecule with the general formula CH2O, typically hydrophilic due to many oxygen atoms, serving as a quick energy source.

Monosaccharide (Simple Sugar)

The monomer of carbohydrates, such as glucose, galactose, or fructose (hexoses), and ribose or deoxyribose (pentoses).

Disaccharide

A carbohydrate formed by joining two monosaccharides, such as sucrose (glucose + fructose) or lactose (glucose + galactose).

Oligosaccharide

A carbohydrate consisting of a few linked sugars, often found on the outer surface of cell membranes as glycolipids or glycoproteins for cell identification.

Polysaccharide

A complex carbohydrate built from many monosaccharides, serving as energy storage (glycogen in humans, starch in plants) or structural support (cellulose).

Glycogen

A branched polysaccharide that serves as the primary form of glucose storage in human liver and muscle cells.

Lipids

A diverse group of hydrophobic biomolecules composed mostly of carbon and hydrogen, including fatty acids, triglycerides, phospholipids, and steroids.

Fatty Acid

The 'monomer' of many lipids, a chain of 4 to 24 carbons with a carboxyl group (COOH) at one end.

Saturated Fatty Acid

A fatty acid containing only single C-C bonds, resulting in a straight chain that is typically solid at room temperature.

Unsaturated Fatty Acid

A fatty acid containing one or more C=C double bonds, resulting in a bent shape that is typically liquid (oil) at room temperature.

Essential Fatty Acids

Fatty acids that cannot be synthesized by the human body and must be obtained from the diet.

Triglyceride (Neutral Fat)

A lipid composed of one glycerol molecule and three fatty acids, serving as the body's primary form of energy storage, thermal insulation, and shock absorption.

Glycerol

A three-carbon carbohydrate that forms the backbone of triglycerides and phospholipids.

Phospholipid

An amphipathic lipid composed of a glycerol backbone, two hydrophobic fatty acid tails, and a hydrophilic phosphate group head, forming the basis of cell membranes.

Amphipathic

Describing a molecule (like a phospholipid) that possesses both hydrophilic (water-loving) and hydrophobic (water-fearing) properties.

Phospholipid Bilayer

The fundamental structure of cell membranes, formed by two layers of phospholipids with their hydrophilic heads facing outward and hydrophobic tails facing inward.

Eicosanoids

A group of signaling lipids derived from fatty acids, serving as chemical messengers between cells (e.g., prostaglandins, leukotrienes).

Steroids (Sterols)

Lipids characterized by a distinctive 17-carbon ring structure, derived from cholesterol, including hormones and bile acids.

Cholesterol

A steroid that stabilizes animal cell membranes, is crucial for nervous system function, and serves as a precursor for other steroids like hormones and bile acids.

Protein

A large, complex biomolecule, typically 50 or more amino acids in length, folded into a specific three-dimensional conformation to perform diverse functions.

Amino Acid

The monomer of proteins, characterized by a central carbon bound to an amine group (NH2), a carboxyl group (COOH), a hydrogen atom, and a variable R radical group (side chain).

R Radical Group (Side Chain)

The variable part of an amino acid that determines its unique chemical properties (e.g., polar, nonpolar) and contributes to protein folding.

Neurotransmitter

A chemical messenger that transmits signals across a chemical synapse from one neuron to another target cell.

Peptide Bond

A covalent bond that joins the carboxyl group of one amino acid to the amine group of another amino acid through dehydration synthesis.

Polypeptide

A chain of many amino acids linked by peptide bonds, constituting a protein or part of one.

Conformation (Protein)

The specific three-dimensional shape of a protein, essential for its function.

Primary Structure (Protein)

The unique linear sequence or order of amino acids in a polypeptide chain.

Secondary Structure (Protein)

Localized, regularly repeating structural patterns formed by hydrogen bonds between the polypeptide backbone, such as alpha helices (twists) and beta sheets (bends).

Tertiary Structure (Protein)

The overall, comprehensive three-dimensional shape of a single polypeptide chain, resulting from interactions between R group side chains.

Disulfide Bridge

A strong covalent bond between two cysteine amino acids, helping to stabilize the tertiary and quaternary structures of proteins.

Quaternary Structure (Protein)

The arrangement of multiple polypeptide chains (subunits) that form a functional protein complex (e.g., hemoglobin).

Receptor (Protein)

A protein, often on a cell surface, that binds specifically to signaling molecules (ligands) and changes its conformation to initiate a cellular response.

Ligand

A molecule that binds specifically to a receptor protein, often triggering a particular cellular response.

Enzyme

A protein that acts as a catalyst, speeding up specific biochemical reactions without being permanently changed during the process.

Catalyst

A substance that increases the rate of a chemical reaction without itself being consumed or undergoing a permanent chemical change.

Activation Energy

The minimum amount of energy required for a chemical reaction to proceed, which enzymes lower to accelerate reaction rates.

Substrate

A reactant molecule that an enzyme acts upon, binding to its active site.

Active Site

The specific region on an enzyme where the substrate binds and the chemical reaction occurs.

Denaturation

The process by which a protein loses its specific three-dimensional shape (conformation) and thus its biological activity, often due to extreme temperature or pH.

Nucleotide

The monomer of nucleic acids, consisting of a pentose sugar, a nitrogenous base, and one or more phosphate groups.

ATP (Adenosine Triphosphate)

A nucleotide that functions as the primary energy currency of the cell, storing and releasing energy by breaking and reforming phosphate bonds.

ADP (Adenosine Diphosphate)

A lower-energy form of ATP, produced when ATP loses a phosphate group and releases energy for cellular work.

Kinase Enzymes

Enzymes that catalyze the transfer of a phosphate group (phosphorylation) from ATP to another molecule.

Nucleic Acids

Polymers of nucleotides, responsible for storing and transmitting genetic information (DNA) and for protein synthesis (RNA).