HAN 200 - Chapter 2 (Chemistry)

Matter

Anything that has mass and occupies space.

States of matter

Solid, liquid, gas.

Solid

Definite shape and volume.

Liquid

Definite volume, changeable shape.

Gas

Changeable shape and volume.

Energy

Capacity to do work or put matter into action.

Types of Energy

Kinetic and potential.

Kinetic energy

Energy in action.

Potential energy

Stored (inactive) energy.

Forms of energy

Chemical, electrical, mechanical, radiant/electromagnetic.

Chemical energy

Stored in bonds of chemical substances (ATP).

Electrical energy

Results from movement of charged particles (action potential).

Mechanical energy

Directly involved in moving matter (mm).

Radiant/electromagnetic energy

Exhibits wavelike properties (visible light, ultraviolet light, X-ray).

Energy form conversions

Energy may be converted from one form to another. However, conversion is inefficient because some energy is “lost” as heat.

Atom

Smallest unit of matter. Made of protons, neutrons, electrons.

Proton

Positive electric charge. Nucleus contains protons.

Neutron

Electrically neutral (uncharged). Nucleus contains neutrons.

Electrons

Negative electric charge. Electrons fly around nucleus (electron cloud).

Atomic number

Number of protons in an atom. Atom usually contains equal number of protons and electrons.

Mass number

Total number of protons and neutrons.

Element

Pure substance containing only atoms of same atomic number, cannot be broken down by ordinary chemical means.

Isotope

Atoms of single element with differing numbers of neutrons.

Major elements of human body

About 96% of body mass. Oxygen, carbon, hydrogen, nitrogen.

Lesser elements of human body

About 3.9% of body mass. Calcium, phosphorus, potassium, sulfur, sodium, chlorine, magnesium, iodine, iron.

Radioisotopes

Valuable tools for biological research and medicine (nuclear medicine: PET scans, contrast MRI). Useful against localized cancers.

Why are radioisotopes dangerous?

Cause damage to living tissue. Radon from uranium decay causes lung cancer.

Example of radioisotope as a tool

Radioactive tracer can show decreased brain activity in Alzheimer’s patient vs normal brain activity in non-Alzheimer’s patient.

Molecule

Two or more atoms bonded together.

Example of molecule

H2, H2O.

Compound

Two or more different kinds of atoms bonded together. Can only be separated by breaking bonds. Homogeneous.

Example of compound

C6H12O6.

Mixture

Most matter exists as mixtures, two or more components physically intermixed. Can be separated physically (straining or filtering). Heterogeneous or homogeneous.

3 types of mixtures

Solutions, colloids, suspensions.

Solutions

Homogeneous mixture, usually transparent (atmospheric air, seawater). Do not scatter light or settle. Has solvent and solute.

Solvent

Present in greatest amount, usually liquid (water in seawater).

Solute

Present in smaller amount (salt in seawater).

Colloids (emulsions)

Heterogeneous mixture, translucent mixtures (cytosol, milk). Large solute particles that scatter light and do not settle.

Suspensions

Heterogeneous mixture (blood). Large solute particles, settle out, and may scatter light.

Types of chemical bonds

Ionic, covalent, hydrogen.

Ionic bond

Electrons transfer from one atom to another (ex: salt). Formed by transfer of valence shell electrons between atoms. Attraction of opposite charges result in ionic bonds.

Covalent bond

Two or more valence electrons are shared. Allows each atom to fill its valence shell at least part of the time.

Hydrogen bond

Attractive force between electropositive hydrogen of one molecule and an electronegative atom of another molecule. Common between dipoles like water. Water molecules bond with other water molecules, forming weak bonds called hydrogen bonds. Water is extremely cohesive.

Anions

Negative charge, gained one or more electrons.

Cations

Positive charge, lost one or more electrons.

What results in ionic bonds?

Attraction of opposite charges.

Example of single covalent bond

Carbon shares four electron pairs with four hydrogen atoms.

Example of double covalent bond

Two oxygen atoms share two electron pairs.

What does the strength of hydrogen bonds in water result in?

High surface tension.

Chemical reactions

Occur when chemical bonds are formed, rearranged, or broken. Represented as chemical equations.

Chemical equations

Contain: molecular formula for each reactant and product, relative amounts of reactants and products, which should balance.

Example of chemical equation

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP

Patterns of chemical reactions

Synthesis, decomposition, exchange.

Synthesis reaction

Anabolic (building up). A + B → AB. Always involve bond formation.

Decomposition reaction

Catabolic (downward). AB → A + B. Reverse synthesis reactions, involve breaking of bonds.

Exchange/displacement reaction

AB + C → AC + B. Bond both made and broken.

Classes of compounds

Inorganic and organic.

Inorganic compound

Do not contain carbon.

Organic compound

Contain carbon, usually large and covalently bonded. Unique to living systems. Many are polymers—chains of similar units (monomers or building blocks). Synthesized by dehydration synthesis, broken down by hydrolysis reactions.

Examples of inorganic compound

Water, salts, many acids and bases.

Examples of organic compound

Carbohydrates, fats, proteins, and nucleic acids.

Water

60%-80% of volume in living cells. Most important inorganic compound in living organisms because of its properties.

Properties of water

High heat capacity, high heat of vaporization, polar solvent properties, reactivity, cushioning.

High heat capacity

Absorbs and releases heat with little temperature change. Prevents sudden changes in temperature.

High heat of vaporization

Evaporation requires large amounts of heat, useful cooling mechanism (sweat).

Polar solvent properties

“Universal solvent”, dissolves and dissociates ionic substances. Forms hydration layers around large charged molecules (ex: protein (colloid formation)). Body’s major transport medium.

Reactivity

A necessary part of hydrolysis and dehydration synthesis reactions.

Cushioning

Protects certain organs from physical trauma (ex: cerebrospinal fluid, tears).

Inorganic compounds: Salts

Ionic compounds that dissociate in water. Contains cations other than H+ and anions other than OH-. Electrolytes conduct electrical currents in solution. Ions play specialized roles in body functions (ex: sodium, potassium, calcium, iron).

Inorganic compounds: Acids and Bases

Both are electrolytes.

Acids

Proton (hydrogen ion) donors (release H+ in solution).

Bases

Proton acceptors (take H+ from solution).

Acid-base concentration

Acid solutions contain H+. As H+ increases, acidity increases.
Alkaline solutions contain bases (OH-). As H+ decreases (or OH- increases), alkalinity increases.

pH

0 to 14. Equal H+ and OH- (pure water). Neutral solutions are pH 7.

Acidic pH

0-6.99

Alkaline (basic) pH

7.01-14

Carbohydrates (hydrated carbon)

Sugars and starches, Contain C, H, and O [(CH2O)n].

3 classes of carbohydrates

Monosaccharides, disaccharides, polysaccharides.

Monosaccharides

Simple sugars - glucose.

Disaccharides

Double sugars - sucrose.

Polysaccharides

Polymers of sugars - glycogen.

Functions of carbohydrates

Major source of cellular fuel (ex: glucose), structural molecules (ex: ribose sugar in RNA)S

Storage of carbohydrates

Glucose is stored in liver and MM as glycogen.

Lipids

Contain C, H, O (less than in carbohydrates), and sometimes P. Insoluble in water.

Types of lipids

Triglycerides, phospholipids, steroids, eicosanoids.

Triglycerides

Energy, protection, insulation.

Phospholipids

Cell membrane.

Steroids

Cholesterol and hormones.

Eicosanoids

Local hormones.

Saturation of Fatty Acids

Saturated fatty acids, unsaturated fatty acids.

Saturated fatty acids

Single bonds between C atoms; maximum number of H. Solid animal fats (butter).

Unsaturated fatty acids

One or more double bonds between C atoms, reduced number of H atoms. Ex: Plant oils (olive oil).

Trans fat

Product of changing unsaturated fat to saturated fat (margarine).

Proteins

Almost all cell functions are performed by proteins. Most abundant organic compounds in the body. Polymers of amino acids (20 types) and joined by peptide bonds.

Function of protein

Support, metabolic regulation, movement, coordination & control, transport, defense, buffering.

Dehydration synthesis

The acid group of one amino acid is bonded to the amine group of the next, with loss of a water molecule.

Hydrolysis

Peptide bonds linking amino acids together are broken when water is added to the bond.

Fibrous (structural) proteins

Strand-like, water insoluble, and stable.

Examples of fibrous (structural) proteins

Keratin, elastin, collagen, and certain contractile fibers.

Globular (functional) proteins

Compact, spherical, water-soluble and sensitive to environmental changes.