Chemical Level of Organization

Flashcards covering the chemical level of organization, including elements, bonding, chemical reactions, water properties, pH, and organic compounds like carbohydrates, lipids, proteins, and nucleic acids.

Chemistry

The study of matter.

Matter

Anything that has mass and occupies space.

Mass

The amount of material in matter; a physical property that determines the weight of an object in Earth’s gravitational field.

Solids

A state of matter that maintains its volume and its shape.

Liquids

A state of matter that has a constant volume but no fixed shape.

Gases

A state of matter that has neither a constant volume nor a fixed shape.

Principal elements

The thirteen most abundant elements to total body weight.

Trace elements

Fourteen elements in the body present in very small amounts.

Oxygen ($O$)

Constitutes 65% of total body weight; a component of water and other compounds; gaseous form is essential for respiration.

Carbon ($C$)

Constitutes 18.6% of total body weight; found in all organic molecules.

Hydrogen ($H$)

Constitutes 9.7% of total body weight; a component of water and most other compounds in the body.

Nitrogen ($N$)

Constitutes 3.2% of total body weight; found in proteins, nucleic acids, and other organic compounds.

Calcium ($Ca$)

Found in bones and teeth; important for membrane function, nerve impulses, muscle contraction, and blood clotting.

Iron ($Fe$)

Essential for oxygen transport and energy capture.

lodine ($I$)

A component of hormones of the thyroid gland.

Protons ($p^+$)

Subatomic particles that have a positive electrical charge.

Neutrons ($n$ or $n^0$)

Subatomic particles that are electrically neutral (uncharged).

Electrons ($e^-$)

Subatomic particles that are much smaller (about $1/1800^{th}$ the mass of protons or neutrons) and bear a negative electrical charge.

Atoms

The components of elements, further composed of subatomic particles.

Isotopes

Atoms of the same element whose nuclei contain different numbers of neutrons.

Atomic Number

The number of protons in an atom.

Atomic Weight

The actual mass of an atom, expressed in daltons; an average mass number reflecting the proportion of different isotopes.

Dalton

A unit of mass also known as the atomic mass unit ($amu$); one dalton is very close to the weight of one proton or one neutron.

Neutral Atoms

Atoms that have no charge because they possess the same number of protons ($p^+$) as electrons ($e^-$).

Ions

Atoms that possess an uneven charge created by the gain or loss of electrons.

Cation

A positively charged ion that has lost one or more electrons.

Anion

A negatively charged ion that has gained one or more electrons.

Inert Elements

Elements that do not react in chemical processes because their outermost energy levels are filled (e.g., Helium, Neon).

Reactive Elements

Elements with unfilled outermost energy levels that achieve stability by gaining, losing, or sharing electrons.

Molecule

Chemical substances consisting of atoms of one or more elements held together by covalent bonds.

Compound

Chemical substances made up of atoms from two or more different elements, regardless of the bond type.

Ionic Bonds

Chemical bonds created by the electrical attraction between cations and anions.

Covalent Bonds

Chemical bonds resulting from the sharing of electrons between atoms.

Single Covalent Bond

The sharing of one pair of electrons between two atoms.

Double Covalent Bond

The sharing of two pairs of electrons between two atoms, such as in an oxygen molecule ($O_2$).

Polar Covalent Bond

A bond involving the unequal sharing of electrons, creating positively and negatively charged portions (e.g., in a water molecule).

Non-polar Covalent Bond

A bond where electrons are shared equally, and there are no positive or negative poles.

Reactants

The reacting substances in a chemical reaction that are rearranged to form products.

Products

The substances generated by a chemical reaction.

Metabolism

All the reactions under way in the cells and tissues of the body at a given moment.

Work

The movement of an object or a change in the physical structure of matter, which requires energy.

Energy

The capacity to perform work.

ATP (Adenosine triphosphate)

The energy currency of cells; a high-energy compound formed from adenosine, ribose, and three phosphate groups.

Potential Energy

Stored energy; energy that has the potential to do work.

Kinetic Energy

The energy of motion.

Decomposition Reaction

A reaction that breaks a molecule into smaller fragments ($AB \rightarrow A + B$).

Hydrolysis

A decomposition reaction involving water where one bond in a complex molecule is broken and components of water ($H$ and $OH$) are added to the fragments.

Catabolism

The collective decomposition reactions of complex molecules within the body's cells and tissues.

Synthesis Reaction

A reaction that assembles smaller molecules into larger molecules ($A + B \rightarrow AB$).

Dehydration Synthesis

The formation of a complex molecule by the removal of a water molecule; also known as condensation.

Anabolism

The collective synthesis of new molecules within the body's cells and tissues; an "uphill" process requiring energy.

Exchange Reaction

A reaction where parts of the reacting molecules are shuffled around to produce new products ($AB + CD \rightarrow AD + CB$).

Equilibrium

A state in a reversible reaction where the rates of the forward and reverse reactions are in balance.

Enzymes

Proteins that act as catalysts to lower the activation energy of chemical reactions.

Exergonic Reaction

A reaction where the products have less energy than the reactants, resulting in a net release of energy.

Endergonic Reaction

A reaction where the products have more energy than the reactants, requiring an energy supply.

Metabolites

All the molecules that can be synthesized or broken down by chemical reactions inside the body.

Nutrients

Essential metabolites normally obtained from the diet.

Organic Nutrients

Nutrients that possess carbon and hydrogen as their primary structural ingredients (e.g., sugars, fats, proteins).

Inorganic Nutrients

Nutrients that generally lack carbon and hydrogen as their primary structural ingredients (e.g., acids, bases, water).

Hydrogen Bond

The attraction between the small positive charge on a hydrogen atom and a small negative charge on an oxygen or nitrogen atom of another polar molecule.

Surface Tension

An effect resulting from hydrogen bonding between water molecules that acts as a barrier, such as preventing small objects from entering the water.

Solution

A uniform mixture of two or more substances.

Solvent

The medium in which other atoms, ions, or molecules are dispersed.

Solutes

The dispersed substances in a solution.

Aqueous Solutions

Solutions where water is the solvent.

Hydrophilic

Molecules that are attracted to and readily interact with water.

Hydrophobic

Molecules that do not readily interact with or dissolve in water (e.g., fats and oils).

Colloid

A solution containing dispersed proteins or other large molecules that do not settle out (e.g., gelatin).

Suspension

A mixture containing large solute particles that will eventually settle out if undisturbed (e.g., whole blood).

Electrolytes

Soluble inorganic substances whose ions will conduct an electrical current in solution.

$$pH$$

The negative logarithm of the hydrogen ion concentration ($[H^+]$) in moles per liter.

Neutral $pH$

A $pH$ of $7.0$, where the concentration of hydrogen ions and hydroxide ions is equal.

Acidic

A solution with a $pH$ below $7.0$, containing more hydrogen ions than hydroxide ions.

Basic (Alkaline)

A solution with a $pH$ above $7.0$, containing more hydroxide ions than hydrogen ions.

Acidosis

An abnormal physiological state caused by low blood $pH$ (below $7.35$).

Alkalosis

An abnormal physiological state caused by high blood $pH$ (above $7.45$).

Acids

Electrolytes that release hydrogen ions ($H^+$) into solution, often called "proton donors."

Bases

Electrolytes that release hydroxide ions ($OH^-$) or otherwise remove hydrogen ions from solution, called "proton acceptors."

Salts

Electrolytes that dissociate to form ions other than $H^+$ or $OH^-$; they do not reflect on the $pH$ scale.

Buffers

Compounds that resist abrupt and large swings in $pH$ by releasing or binding hydrogen ions.

Monomers

The basic building blocks of organic molecules.

Polymers

Large molecules constructed of repeating units of monomers.

Carbohydrates

Organic compounds containing carbon, hydrogen, and oxygen, usually in a $1:2:1$ ratio; they serve as an energy source.

Monosaccharides

Simple sugars (e.g., glucose, fructose) that are the simplest form of carbohydrate.

Isomers

Molecules with the same molecular formula but different structures (e.g., glucose and fructose, both $C_6H_{12}O_6$).

Disaccharides

Two monosaccharides joined together by dehydration synthesis (e.g., sucrose, lactose, maltose).

Polysaccharides

Complex carbohydrates resulting from repeated dehydration synthesis (e.g., glycogen in animal cells).

Lipids

Organic compounds that are generally insoluble in water, including fats, oils, and waxes.

Fatty Acids

Long carbon chains with hydrogen atoms attached, ending in a carboxylic acid group ($-COOH$); building blocks of lipids.

Saturated Fatty Acid

A fatty acid in which each carbon atom in the hydrocarbon tail has four single covalent bonds.

Unsaturated Fatty Acid

A fatty acid in which one or more single covalent bonds have been replaced by double covalent bonds.

Glycerides

Lipids formed by the attachment of fatty acids to a molecule of glycerol.

Steroids

Large lipid molecules sharing a distinctive four-ring carbon framework (e.g., cholesterol, estrogen, testosterone).

Phospholipids

Lipids where a phosphate group links a diglyceride to a nonlipid group; essential components of cell membranes.

Micelles

Droplets formed by phospholipids and glycolipids in water, with hydrophilic heads facing out and hydrophobic tails facing in.

Proteins

The most abundant organic components of the body, formed from amino acids; they perform functions such as catalysis, structural support, and movement.

Amino Acids

The building blocks of proteins, consisting of a central carbon, an amino group ($-NH_2$), a carboxylic acid group ($-COOH$), and a variable $R$ group.

Peptide Bond

A covalent bond that connects the carboxylic acid group of one amino acid to the amino group of another.

Polypeptide

A linear chain of amino acids held together by peptide bonds.