Chapter 2 Human and anatomy and physiology

Mass

The amount of matter in an object, typically measured in grams or kilograms.

Atoms

The basic units of a chemical element, consisting of protons, neutrons, and electrons

Subatomic particles

Particles that are smaller than an atom, including protons, neutrons, and electrons.

Protons

Positively charged particles found in the nucleus of an atom

Atomic number

The number of protons in the nucleus of an atom.

Mass number

The total number of protons and neutrons in an atom's nucleus.

Element

A substance that cannot be broken down into simpler substances by chemical means.

Isotopes

Atoms of the same element that have different numbers of neutrons

Inert

Not chemically reactive.

Inert gases

Gases that do not readily react with other substances.

Reactive

Chemically active; likely to undergo a chemical change

Cation

A positively charged ion

Anion

A negatively charged ion

Chemical bonds

The force of attraction that holds atoms or ions together

Compound

A substance formed when two or more chemical elements are chemically bonded together.

Ionic bonds

Bonds formed when one atom gives up one or more electrons to another atom.

Covalent bonds

Bonds formed when atoms share one or more pairs of electrons

Nonpolar molecules

Molecules in which the electron sharing produces no localized positive and negative regions

Single covalent bond

A bond in which two atoms share one pair of electrons

Double covalent bond

A bond in which two atoms share two pairs of electrons

Polar molecule

A molecule with a net dipole as a result of opposing charges.

Polar covalent bonds

A type of bond that forms when electrons are not shared equally between atoms.

Hydrogen bond

A weak bond between two molecules resulting from an electrostatic attraction.

Chemical notation

A system of symbols and notation conventions used to represent chemical reactions

Formula

A way of expressing information symbolically.

Balanced equation

A chemical equation with the same number of atoms of each element on both sides of the equation.

Activation energy

The minimum quantity of energy that a reactant must possess to undergo a specific reaction.

Enzymes

Proteins that speed up the rate of chemical reactions.

Catalysts

Substances that increase the rate of a reaction without being consumed in the process.

Metabolic pathway

A series of chemical reactions in a cell.

Exergonic

Reactions that release energy.

Decomposition

A type of chemical reaction in which one reactant breaks down into two or more products.

Hydrolysis

A chemical in which water is used to break down a compound.

Catabolism

The breakdown of complex molecules in living organisms to form simpler ones

Dehydration synthesis

A chemical reaction in which two molecules are joined together with the removal of a water molecule.

Anabolism

The synthesis of complex molecules in living organisms from simpler ones.

Equilibrium

A state in which the forward and reverse reactions balance each other out.

Exchange reaction

A type of chemical reaction in which parts of the reacting molecules are shuffled to produce new combinations.

Ionization

The process by which an atom or molecule acquires a positive or negative charge by gaining or losing electrons.

Electrolytes

Substances that disassociate into ions in solution and have the ability to conduct electricity.

Dissociation

The breaking apart of a compound into its individual ions in solution.

Hydration sphere

The cluster of water molecules that surrounds an ion in a solution.

Colloid

A mixture in which one substance is divided into minute particles and dispersed throughout a second substance.

Suspension

A mixture in which particles are dispersed throughout a liquid or gas but settle out over time

Hydrophilic

Having an affinity for water; water-loving.

Hydrophobic:

Lacking an affinity for water; water-fearing.

Hydrogen ion (H+)

A positively charged ion formed of a hydrogen atom that has lost its electron.

Hydroxide ion (OH-)

A negatively charged ion made of one oxygen atom bonded to one hydrogen atom.

pH

A measure of the acidity or basicity of a solution.

Acidosis

A condition in which the blood's pH is below 7.35

Alkalosis

A condition in which the blood's pH is above 7.45.

Acidic

Having a pH less than 7.

Neutral

Having a pH of 7

Basic

Having a pH greater than 7.

Alkaline

Another term for basic; having a pH greater than 7

Hydrochloric acid

A strong acid commonly found in the stomach

Base

A substance that can accept a proton (H+) from another substance.

Sodium hydroxide

A strong base used in various industrial applications

Carbonic acid

A weak acid formed when carbon dioxide dissolves in water.

Bicarbonate ion

An ion that acts as a buffer in the blood, helping to maintain a stable pH

Salt

A compound formed when an acid reacts with a base

Buffers

Compounds that prevent drastic changes in internal pH by removing or releasing hydrogen ions (H+).

Buffers

Substances that minimize changes in the concentrations of H+ and OH- in a solution, thus stabilizing the pH

Carbohydrate

Organic compounds made up of carbon, hydrogen, and oxygen, typically in a 1:2:1 ratio; serve as a primary source of energy for organisms.

Monosaccharide

The simplest form of carbohydrates, e.g., glucose and fructose.

Glucose

A monosaccharide sugar that's an important energy source in living organisms.

Fructose

A monosaccharide found in fruits and honey

Disaccharide

A sugar molecule consisting of two monosaccharides, e.g., sucrose.

Polysaccharides

Long-chain carbohydrates, e.g., starches and glycogen.

Glycogen

A multi-branched polysaccharide that serves as a form of energy storage in animals.

Lipids

Organic compounds that are fatty acids or derivatives; insoluble in water but soluble in organic solvents.

Fatty acids

Building blocks of lipids.

Carboxyl group

A functional group present in organic acids, consisting of a carbon atom bonded to an oxygen atom by a double bond and to a hydroxyl group.

Saturated fatty acid

Fatty acid chains that have all single bonds between carbons; solid at room temperature.

Unsaturated fatty acid:

Fatty acid chains that have one or more double bonds; liquid at room temperature.

Glycerol:

A simple polyol compound; a backbone for triglycerides and phospholipids

Fats

Lipids that are solid at room temperature

Monoglyceride

A glycerol molecule with one fatty acid attached

Diglyceride

A glycerol molecule with two fatty acids attached

Triglyceride

A glycerol molecule with three fatty acids attached

Structural lipids

Lipids that are components of cell membranes or play specific roles in cellular function.

Steroids

A type of lipid molecule with a characteristic structure of four rings; includes hormones and cholesterol.

Cholesterol:

A sterol lipid that's a key component in cell membranes and a precursor for various hormones.:

Phospholipids

Lipids containing a phosphate group; a major component of cell membranes..

Glycolipids

Lipids with a carbohydrate attached; important for cell recognition.

Proteins

Large molecules composed of amino acid chains; serve a variety of functions including structural, enzymatic, and transport roles.

Amino acids

Building blocks of proteins.

Peptide bond

The chemical bond that forms between amino acids.

Peptide

A short chain of amino acids.

Dipeptides

Two amino acids linked by a peptide bond.

Polypeptides

Long chains of amino acids.

Primary structure

The sequence of amino acids in a protein.

Secondary structure

The localized folding or coiling of the polypeptide chain due to hydrogen bonding.

Tertiary structure

The overall three-dimensional shape of a protein due to interactions among its side chains.

Quaternary structure

The arrangement of multiple protein subunits.

Hemoglobin

A protein in red blood cells that carries oxygen.

Keratin

A protein found in hair, nails, and the outer layer of skin.

Collagen

The main structural protein in connective tissues.

Denaturation

A process where a protein loses its native shape due to environmental changes.

Enzymes

Proteins that act as biological catalysts, speeding up reactions without being consumed.