chemistry of life

matter

anything that takes up space and has weight; composed of elements

Elements

composed of chemically identical atoms

bulk elements

required by the body in large amounts

Trace elements

required by the body in small amounts

Atoms

smallest particle of an element that retains the properties of that element and consists of protons, neutrons, and electrons.

proton

a subatomic particle with a positive charge found in the nucleus of an atom, contributing to the atom's mass.

neutron

carries no electrical charge

electron

a subatomic particle with a negative charge that orbits the nucleus of an atom and is involved in chemical bonding.

Nucleus

central part of the atom, composed of protons and neutrons, electrons move around the nucleus

atomic number

the number of protons in the nucleus of one atom, equals the number of electrons in the atom and determines the element's identity.

Atomic weight

the number of protons plus the number of neutrons in one atom. electrons do not contribute to the weight of the atom

Isotopes

atoms with the same atomic numbers but with different atomic weights. atoms with the same number of protons and electrons but different number of neutrons: EX: oxygen. unstable isotopes are radioactive; they emit energy or atomic fragments

molecule

particle formed when two or more atoms chemical combine

compound

particle formed when two or more atoms of different elements chemically combine

molecular formulas

depict the elements present and the number of each atom present in the molecule EX: H2, C6H12O6 (glucose), H2O

Bonding atoms first shell

2 electrons

Bonding atoms Second shell

8 electrons

Bonding atoms third shell

8 electrons

ion

an atom that gains or loses electrons to become stable, an eclectically charged atom

Cation

a positively charged ion, formed when an atom loses electrons

Anion

A negatively charged ion, formed when an atom gain electron

ionic bond

an attraction between a cation and an anion, formed when electrons are transferred from one atom to another atom: EX sodium Ion (Na+) and Chloride ion (Cl-) they bond to make sodium chloride

covalent bond

a type of bond that involves the sharing of electron pairs between two atoms. this sharing allows each atom to attain a full balance shell, leading to better stability. EX two hydrogen atoms form single bonds

structural formulas

show how atoms bond and are arranged in various molecules

polar molecules

molecule with a slightly negative end and a slightly positive end, results when electrons are no shared equally in covalent bonds water is an important polar molecule

hydrogen bond

a weak attraction between the positive end of one polar molecule and the negative end of another polar molecule, formed between water molecules, important for protein and nucleic acid structure

Chemical reactions

occur when chemical bonds form or break among, ions, or molecules

reactants

the starting materials of the reaction - the atoms, ions, or molecules ex: NaCl

products

substances formed at the end of the chemical reaction EX: Na+ + Cl-

synthesis reaction

also known as a direct combination reaction, occurs when two or more simple elements or compounds combine to form a more complex product. EX: A+B —> AB

decomposition reaction

chemical bonds are broken to form a simpler chemical structure EX: AB —> A+B

exchange reaction

chemical bonds are broken, and new bonds are formed EX: AB + CD —> AD + CB

reversible reaction

the products can change back to the reactants

electrolytes

substances that release ions in water, they have a natural positive or negative charge EX:

NaCl → Na+ + Cl-

Acids

electrolytes that dissociate to release hydrogen ions in water Ex: HCL → H+ +Cl-

Bases

substances that release ions that can combine with hydrogen ions EX: NaOH → Na+ + OH-

Salts

electrolytes formed by the reaction between an acid and a base EX: HCL + NaOH → H2O +NaCl

pH Scale

indicates the concentration of hydrogen ions in a solution

neutral

pH 7; indicates equal concentration of H+ and OH-

Acidic

pH less than 7; indicates a greater concentration of H+, to reduce this you add a base

Basic or alkaline

pH greater than 7; indicates a greater concentration of OH-

organic molecules

contains C and H, usually larger than inorganic molecules dissolve in water and organic liquids EX: carbohydrates, proteins, lipids, and nucleic acids

inorganic molecules

generally, do not contain C, usually smaller than organic molecules, usually dissociate in water, forming ions EX: water, oxygen, carbon dioxide, and inorganic salts

water (inorganic)

two thirds of the weight of an adult human major component of all body fluids, medium for most metabolic reactions, important role in transporting chemicals in the body, absorbs and transports heat

oxygen (inorganic)

used by organelles to release energy from nutrients in order to drive cell’s metabolic activities, necessary for survival

carbon dioxide (inorganic)

waste product released during metabolic reactions, must be removed from the body, the exception contains carbon but is still inorganic

inorganic salts

abundant in body fluids, sources of necessary ions (Na+, Cl-, K+, Ca2+), play important roles in metabolism

Carbohydrates (organic)

provide energy to the cells, supply materials to build cell structures, water soluble, contains C, H, and O, ratio of H to ) close to 2:1 (C6H12O6)

monosaccharides

single sugar molecules that cannot be hydrolyzed into smaller carbohydrates. they are the most basic units of carbohydrates. consist of carbon, hydrogen, and oxygen atoms (CH2O) EX: glucose, fructose

disaccharides

sugars formed by the combination of two monosaccharides linked by a glycosidic bond, general chemical formula of C12H22O11 EX: Sucrose, lactose

polysaccharides

polymers of simple sugars connected together by glycosidic linkages, which are covalent connections, general formula C6H10O5 EX: Glycogen, cellulose

building block to polysaccharide

monosaccharide

building block to lipids

fatty acids, glycerol

building block to nucleic acids

nucleotides

building block to proteins

amino acids

lipids (organic)

soluble in organic solvents; insoluble in water, used primally for energy. most common lipid in the body contains C, H, and O but less O than carbohydrates (C57H110O6), building blocks are 1 glycerol and 3 fatty acids per molecules, saturated and unsaturated

phospholipids (organic lipids)

building blocks are 1 glycerol, 2 fatty acids, and 1 phosphate per molecule, hydrophilic, and hydrophobic, major component of cell membranes

steroid (organic lipids)

four connected rings of carbon widely distributed in the body, various functions, component of the cell membrane, used to synthesis hormones, cholesterol

proteins (organic)

structural material, energy source, hormones, receptors, enzymes, antibodies, building blocks are amino acids

amino acids are held together by what

peptide bonds

proteins structure

1. primary structure, 2. secondary structure, 3. tertiary structure, 4. quaternary structure

nucleic acids (organic)

carry genes, encode amino acid sequences of proteins, building blocks are nucleotides

DNA

double polynucleotide

RNA

single polynucleotide

nitrogenous bases

Adenine pairs with thymine

cytosine pairs with Guanine