Ch 2. Chemistry of Life: Organic and Inorganic Overview

Chemistry

Study of substances' composition and properties.

Organic Chemistry

Study of molecules containing Carbon and Hydrogen.

Inorganic Chemistry

Study of molecules not containing both C and H.

Matter

Anything that occupies space and has mass.

Solid

Matter with a definite shape and volume.

Liquid

Matter that has a definite volume but no shape.

Gas

Matter that has neither definite shape nor volume.

Plasma

Ionized gas with free-moving charged particles.

Atom

Smallest unit of matter with unique properties.

Element

Matter made of a single type of atom.

Bohr Model

Model depicting electrons orbiting a nucleus.

Atomic Number

Number of protons in an atom's nucleus.

Atomic Mass

Total weight of protons, neutrons, and electrons.

Dalton (D)

Unit of mass for atomic particles, ~1 atomic weight unit.

Isotopes

Atoms of the same element with different neutron counts.

Radioisotopes

Unstable isotopes that emit radiation.

Valence Electrons

Electrons in the outer shell determining chemical properties.

Covalent Bonds

Strong bonds formed by sharing electron pairs.

Polar Covalent Bonds

Unequal sharing of electrons between atoms.

Nonpolar Covalent Bonds

Equal sharing of electrons between atoms.

Electronegativity

Atom's tendency to attract electrons.

Ionic Bonds

Bonds formed by attraction of oppositely charged ions.

Cations

Positively charged ions formed by losing electrons.

Anions

Negatively charged ions formed by gaining electrons.

Hydrogen Bonds

Weak bonds between hydrogen and electronegative atoms.

Solvent

Substance that dissolves another substance, often water.

Solute

Substance dissolved in a solvent.

Molecule

Combination of two or more atoms.

Compound

Molecule containing two or more different elements.

Trace Elements

Elements that account for 0.7% of body composition.

Physiologic Role of Elements

24 elements essential for human physiological functions.

Oxygen

65% of body composition, vital for respiration.

Carbon

18% of body composition, backbone of organic molecules.

Hydrogen

10% of body composition, involved in chemical reactions.

Nitrogen

3% of body composition, essential for amino acids.

Strength of Bonds

Covalent > Ionic > Hydrogen in terms of stability.

Hydrophilic Solution

Solute that dissolves in water (H2O).

Hydrophobic Solution

Solute that does not dissolve in water (H2O).

Colloid

Heterogeneous mixture with insoluble solutes suspended.

Suspension

Heterogeneous mixture where solutes settle out.

Metabolism

Total of all chemical reactions in the body.

Anabolic Reactions

Endergonic reactions creating larger molecules from smaller ones.

Catabolic Reactions

Exergonic reactions breaking down larger molecules into smaller ones.

Reaction Rates

Factors influencing the speed of chemical reactions.

Concentration

Higher reactant concentration increases reaction rate.

Temperature

Increased temperature speeds up reaction rates.

Enzymes

Proteins that catalyze reactions by lowering activation energy.

Water (H2O)

Unique molecule with special properties due to polarity.

Cohesion

Water molecules stick together due to hydrogen bonding.

Surface Tension

Insects can walk on water due to cohesive forces.

Solvent

Water dissolves salts and charged particles effectively.

Temperature Moderation

Water stabilizes temperatures, protecting organisms.

Acid

Substance that donates H+ ions in water.

Base

Substance that accepts H+ ions in water.

pH Scale

Logarithmic scale measuring hydrogen ion concentration.

Acidity

Increases as pH scale decreases.

Alkalinity

Increases as pH scale increases.

Neutral Solution

Achieved at pH of 7 with equal H+ and OH-.

pH Calculation

pH = -log(H+) expresses hydrogen ion concentration.

Buffers

Substances that stabilize pH by neutralizing excess ions.

Macromolecules

Large organic molecules essential for biological functions.

Carbon Skeleton

Structure formed by carbon atoms in organic molecules.

Organic Molecules

Contain carbon and hydrogen, forming the basis of life.

Monomer

Simplest unit of each organic macromolecule.

Monomer

Basic building block of polymers, e.g., glucose.

Polymer

Multiple monomers linked together to form larger molecules.

Functional Groups

Specific arrangements affecting molecule properties in compounds.

Lipids

Diverse macromolecules unified by hydrophobic properties.

Hydrophobic

Substances that repel water molecules.

Nonpolar Lipid Bonds

Lipid bonds that do not interact with water.

Triglycerides

Fats with three fatty acid chains.

Fatty Acids

Carboxylic acids with long hydrocarbon chains.

Saturated Fat

Fat with only single carbon bonds.

Unsaturated Fat

Fat with at least one double carbon bond.

Polyunsaturated Fat

Fat with multiple double carbon bonds.

Steroid

Lipid with 17 carbons in four rings.

Cholesterol

Parent steroid for all other steroids.

Phospholipids

Lipids with two fatty acids and a phosphate group.

Phospholipid Bilayer

Membrane structure with hydrophobic tails inward.

Carbohydrates

Organic compounds of carbon, hydrogen, and oxygen.

Monosaccharide

Simplest form of carbohydrates; single sugar unit.

Disaccharide

Two monosaccharides linked together.

Polysaccharide

Long chains of monosaccharides; complex carbohydrates.

Cellulose

Polysaccharide forming plant cell walls.

Glycogen

Storage form of glucose in animals.

Proteins

Complex macromolecules made of amino acids.

Amino Acids

Building blocks of proteins; 21 types used.

Peptide Bonds

Covalent bonds linking amino acids together.

Polypeptide

Chain of three or more amino acids.

Nucleic Acids

Biopolymers essential for all known forms of life.

Nucleotide

Monomer of nucleic acids; includes phosphate group.

DNA

Genetic material of all cells and viruses.

RNA

Involved in protein synthesis and genetic material.

ATP

Main energy currency of cells.

High Energy Bonds

Bonds in ATP that release energy when broken.