Vocabulary Chapter 2: Basic Chemistry

Matter

all tangible materials that occupy space and have mass.

Atom

a tiny particle that cannot be subdivided into smaller substances without losing its properties.

Protons (p+)

positively charged, found in the nucleus

Neutrons (n⁰)

no charge, found in the nucleus

Electrons

negatively charged, surround the nucleus

Isotopes

variant forms of the same element that differ in the number of neutrons.

Radioactive Isotopes

an unstable version of a chemical element

Molecule

a distinct chemical substance that results from two or more atoms.

Compound

a molecule composed of two or more different elements.

Chemical Bonds

result when two or more atoms share, donate (lose), or accept (gain) electrons.

Valence

the number of electrons in the outermost shell of an element. Determines the degree of reactivity and the type of bonds it can make.

Covalent Bonds

from between atoms that share electrons rather than donating or receiving them.

Polar Molecule

results when a molecule is formed between two molecules that have different electronegativity or ability to attract electrons.

Nonpolar Molecule

molecules formed when atoms have similar electronegativity.

Ionic Bonds

formed when electrons are transferred completely from one atom to another.

Ionization

the formation of charged particles when a molecule formed by ionic bonds dissolves in a solvent.

Cations

positively charged ions

Anions

negatively charged ions

Electrolytes

substances that release ions when dissolved in water.

Hydrogen Bonds

formed due to attractive forces between nearby atoms or molecules. This bond is temporary and easily disrupted.

van der Waals forces

weak attractions between molecules that show polarity. Neighboring groups with slight attractions will interact and remain associated.

Reactants

molecules entering or starting a chemical reaction.

Products

substances left by a chemical reaction

Catalysts

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

Solution

a mixture of one or more substances that cannot be separated by filtration or settling.

Solute

a substance that is uniformly dispersed in a solvent.

Solvent

a dissolving medium (water is the most common solvent in natural systems).

Each ions becomes….

hydrated

Hydrophilic

molecules such as salt or sugar that attract water to their surface.

Hydrophobic

nonpolar molecules such as benzene that repel water.

Amphipathic

molecules such as phospholipids that have both hydrophilic and hydrophobic properties.

Concentration

expresses the amount of solute dissolved in a certain amount of solvent. Can be calculated by weight, volume, or percentage.

Acidic Solution

occurs when a component dissolved in water releases excess hydrogen ions (H+).

Basic Solution

occurs when a component dissolved in water releases excess ions (OH^-).

pH Scale

1. Measures the acid and base concentrations of solutions

2. Ranges from 0 (most acidic) to 14 (most basic).

3. Logarithmic scale: each increment represents a tenfold change in the concentration of ions.

4. Measurement of pH: pH= -log[H⁺]

Inorganic chemicals

molecules that lack the basic framework of the elements of carbon and hydrogen.

• NaCl

• Mg₃(PO4)₂

• CaCO₃

• CO₂

Organic chemicals

molecules that contain the basic framework of the elements of carbon and hydrogen.

• Simplest: CH₄

• Complex: antibody molecules with a molecular weight of 1,000,000.

Describe Carbon

1. Is the fundamental element of life.

2. Ideal atomic building block to form the backbone of organic molecules.

3. Four electrons in the outer orbital can be shared with for other atoms, including carbon.

Biochemistry

explores the compounds of life.

What are the four main families of biochemicals?

1. Carbohydrates

2. Lipids

3. Proteins

4. Nucleic acids

Macromolecules

• Assembled from smaller molecular subunits or building blocks.

• Often very large compounds

Polymerization

Monomers (repeating subunits) are bound into varying lengths called polymers.

What are the functions of macromolecules?

1. Structural components

2. Molecular messengers

3. Energy sources

4. Enzymes (biochemical catalysts)

5. Nutrient stores

6. Sources of genetic information

Saccharide

a sugar

Monosaccharide

a simple sugar containing from 3-7 carbons.

Disaccharide

combination of two monosaccharides.

Polysaccharide

polymer of five or more monosaccharides.

Glycosidic bonds

carbons on adjacent sugar units are bonded to the same oxygen atom like links in a chain.

Dehydration synthesis

occurs in the polymerization process when one carbon group gives up an H and the other carbon group gives up an OH, forming water.

Lipids

• Operational term for substances that are not soluble in polar solvents but are soluble in nonpolar solvents.

• Long or complex hydrocarbon chains that are hydrophobic.

Triglycerides

1. Storage lipids that includes fats and oils.

2. Composed of a single molecule of glycerol bound to three fatty acids.

Glycerol (Triglycerides)

3-carbon alcohol with three OH groups that serve as binding sites.

Fatty acids

long chain hydrocarbons with a carboxyl group at the end.

Saturated fatty acid

(“unhealthy” fats): all carbons in the fatty acid chain are single-bonded to 2 other carbons and 2 hydrogens.

Unsaturated fatty acid

(“healthy” fats): a fatty acid in which at least one double bond exists between carbon atoms.

Phospholipids

1. contain only two fatty acids attached to a glycerol.

2. third binding site holds a phosphate group bound to an alcohol.

3. have a hydrophilic region and a hydrophobic region.

4. allows the molecule to form bilayers and membranes.

Proteins

predominant molecule in cells. It determines the structure, behavior, and unique qualities of organisms.

Amino acids

1. building blocks of proteins

2. exist in 20 different naturally occurring forms

3. linked by peptide bonds

Peptide

molecule composed of short chains of amino acids

Polypeptide

1. has more than 20 amino acids

2. not all polypeptides are large enough to be considered proteins.

Primary (1*) structure (Protein structure and diversity)

the type, number, and order of amino acids.

Secondary (2^*) structure (Protein structure and diversity)

arises when functional groups on the outer surface of the molecule interact with each other.

Tertiary (3^*) structure (Protein structure and diversity)

torsion caused by interaction between functional groups.

• covalent sulfide bonds

Quaternary (4^*) structure

large multiunit proteins formed by more than one polyprotein.

Enzymes

1. catalysts for chemical reactions in cells

2. specificity comes the unique patterns in enzyme binding sites.

Antibodies

complex glycoproteins with specific attachment regions for microorganisms.

Native state

the functional, three-dimensional form of a protein.

Denature

disruption of the native state of a protein through heat, chemicals, acid or other means, making the protein non-functional.

Deoxyribonucleic Acid (DNA)

contains a special coded genetic program with detailed instructions for each organism’s heredity.

Ribonucleic Acid (RNA)

helper molecules responsible for translating and carrying out the instructions of DNA.

DNA and RNA are composed of repeating __________.

nucleotide subunits.

Adenosine Triphosphate (ATP)

releases energy when the bond is broken between the 2^nd and 3^rd phosphates.