micro lecture ch 2

• 3/4 of the earth's surface is water
• 2/3 of the human body is water
• all organisms require water
• water is essential for cell structure (giving it volume) and function
• water participates in many chemical reactions necessary to sustain life (H+ and OH-)
• water is the only common substance to exist in the natural environment in all three physical states of matter-solid, liquid, and gas

acid-an acid is a substance that dissociates into one or more H+

base-a substance that dissociates into one or more OH+

salt-a substance that dissociates into cations and anions, neither of which is H+ or OH-

pH-A measure of the hydrogen ion concentration, it is equal to - log [H+].

• increasing H+ increases acidity
• increasing OH+ increases alkalinity

Most organisms grow best between 6.5 and 8.5

• organic compounds always contain carbon AND hydrogen
• -from living sources

• inorganic compounds typically lack carbon
• -metals
• -gases
• -water

the replaced group that forms something else by removing a hydrogen group from a chemical

responsible for most of the chemical properties of a particular organic compounds

• carbon
• hydrogen
• oxygen
• with hydrogen and oxygen in a 2:1 ratio

simple lipids are built from 2 subunits (a glycerol subunit and ONE fatty acid subunit)

complex lipids have more than one fatty acid subunit

steroids a type of fat; carbon skeleton of 4 rings

amino acids

nucleotide

• typically lack carbon
• -metals
• -gases
• -water

A compound that does not contain hydrocarbon groups

• always contain carbon and hydrogen
• -from living sources

two poles (one neg and one pos)

a molecule (such as water) with opposite charges on opposite sides

A molecule that has a dipole moment due to its having unsymmetrical polar bonds.

A molecule with regions of partial negative, and partial positive charges.

In chemistry, a polar molecule is a molecule in which the centers of positive and negative charge distribution do not converge. These molecules are characterized by a dipole moment which measures their polarity.

what does the dissolving

• a. A substance in which another substance is dissolved, forming a solution.
• b. A substance, usually a liquid, capable of dissolving another substance.

what is dissolved

• the substance dissolved in solvent to form a solution.
• dorland

• homogeneous (uniform) mixture of two or more kinds of molecules, atoms or ions
• mixture of solute and solvent

an acid is a substance that dissociates into one or more H+ (hydrogen ion)

a chemical compound that dissociates in solution, releasing hydrogen ions and lowering the solution pH (a proton donor). An acidic solution has a pH below 7.0.

a base is a substance that dissociates into one or more OH+

a substance that combines with acids to form salts; a substance that dissociates to give hydroxide ions in aqueous solutions; a substance whose molecule or ion can combine with a proton (hydrogen ion); a substance capable of donating a pair of electrons (to an acid) for the formation of a coordinate covalent bond

Acidic and basic are two extremes that describe a chemical property chemicals. Mixing acids and bases can cancel out or neutralize their extreme effects. A substance that is neither acidic nor basic is neutral.

The pH scale measures how acidic or basic a substance is. The pH scale ranges from 0 to 14. A pH of 7 is neutral. A pH less than 7 is acidic. A pH greater than 7 is basic.

A solution composed of an acid and its conjugate base that serves to moderate the pH of the solution

removal of water

• A dehydration reaction is a chemical reaction between two compounds where one of the products is water or ammonia.
• Also Known As: condensation reaction

In chemistry and the biological sciences, a dehydration reaction is usually defined as a chemical reaction that involves the loss of water from the reacting molecule. Dehydration reactions are a subset of elimination reactions. Because the hydroxyl group (-OH) is a poor leaving group, having a Brønsted acid catalyst often helps by protonating the hydroxyl group to give the better leaving group, -OH2+. Dehydration reactions are the same thing as dehydration synthesis, and are often used interchangeably

• very common and very important for cell construction and as energy sources and used for reproduction of microbes
• organic molecules that contain carbon, oxygen and with the formular (CH₂O)_n
• structure:
• -monosaccharides...consisting of one sugar unit
• -disaccharides...consisting of two sugar units
• -poly saccharides..consisting of many sugar units

compounds consisting of atoms of carbon, hydrogen and oxygen, with hydrogen and oxygen in a 2:1 ratio

• most important monosaccharide=glucose: C₆H₁₂O₆ important because
• it forms a ring structure in solution, major nutrient for cells (builds all materials you need to grow and live), carbon skeletons serve as raw material for synthesis of other types of small organic molecules
• water soluble (dissolves in water)
• often linked to form disaccharide for transport
• Frutose: found in fruits

• contain from 3-7 carbon atoms
• may form disaccharides and polysaccharides by dehydration synthesis

• formed when two monosaccharides are joined in a dehydration synthesis reaction
• sucrose (table sugar) is a disaccharide formed by bonding a glucose to a fructose
• disaccharides can be broken down by hydrolysis << breaking off of water(which is what your digestive system does when you eat sucrose)

• breaking off of water
• when you add one glucose molecule to a fructose molecule you release a water molecule

• many sugars
• glycogen: storage form of glucose in animals, long chains, highly branched. easily broken down via enzyme catalyzed hydrolysis to glucose
• Starch: storage form of glucose in plants (potatoes, wheats, etc)
• cellulose: also made of glucose monomers but structurally different than starch (makes paper and wood)
• component of tough walls that encase plant cells, not readily broken down
• chitin: structural reinforcement also, used by mushrooms (cell walls), crustaceans, insects and spiders (exoskeletons)

• insoluble in water (polar) but soluble in oil (non-polar)
• no single structural unit, all different molecular structure
• -glycerides (common fats)
• -steroids (used for hormones)
• -phospholipids (extremely important in plasma membranes of all cells)
• lipids have many C-H bonds (just like carbohydrates the more bonds=more energy)
• their importance to organisms include:
• -energy storage
• -cell membrane structure
• -hormones and vitamins

• built from 2 subunits
• -glycerol: 3-C alcohol with 3 OH groups which forms the backbone of the lipid molecule
• -fatty acids: long chains of C-H (often 16-18 carbons long-hence the insolubility)
• saturated:
• single bonds between carbons
• chains lay flat
• decreased reactivity
• solid at room temp (lard, butter)
• most animal fats
• unsaturated:
• one or more double bonds which causes "kinks" in chains
• therefore increasing reactivity
• liquid at room temp (olive oil, cod liver oil)
• most plant and fish fats

1-3 fatty acid chains per glyceral molecule

great energy storage

• long chains of C-H (often 16-18 carbons long-hence the insolubility)
• saturated:
• single bonds between carbons
• chains lay flat
• decreased reactivity
• solid at room temp (lard, butter)
• most animal fats
• unsaturated:
• one or more double bonds which causes "kinks" in chains
• therefore increasing reactivity
• liquid at room temp (olive oil, cod liver oil)
• most plant and fish fats

1-3 fatty acid chains per glyceral molecule

great energy storage

-glycerol: 3-C alcohol with 3 OH groups which forms the backbone of the lipid molecule

• glycerol backbone with 2 fatty acid tails
• phosphate group PO₄ attached
• because of that phosphate group:
• -they have a charged molecule
• -hydrophylic head/hydrophobic fatty acid tails

• because of the hydrophobic tails, they form lipid bilayer at cell surface
• important member of cell membranes

water-hating; do not interact with water (oil (hydrophobic) and water)

water loving

• carbon skeleton of 4 rings
• vary in functional groups attached and therefore vary in function
• cholesterol
• testosterone
• estrogen

• account for almost 50% of dry weight of cells
• instrumental for many cell functions including:
• -structural support and movement (bone/cartilage)
• -storage/transport molecules (hemoglobin is a protein that transports oxygen in our blood)
• -hormones (insulin-sugar breakdown hormones)
• -enzymes (the molecules that control cellular reactions; making; breaking)
• -many bacterial toxins are proteins made by bacteria

• made of chains of amino acids
• 20 amino acids are the basis of all proteins
• -differ in side chain (R group)
• shape of chain folding is specific

protein function depends on its shape or conformation

• building blocks of protein structure
• exist in either of two stereoisomers, D or L
• L-forms are most often found in nature

peptide bonds are covalent bonds between amino acids, formed by dehydration synthesis

• basic structure: the list (chain) of amino acids (AA)
• specific and unique AA sequence
• -are polymers of amino acids
• -there are 20 different common amino acids

the interaction of parts of the AA chain

parts of AA chain bonded together via hydrogen bonds into helical structure (alpha helix) or sheet structure

when the helix folds irregularly, forming disulfide bonds, hydrogen bonds, and ionic bonds between amino acids in the chain

consists of two or more polypeptides

• change in 3D structure when chemical environment of protein changed
• ex:
• pH, salt concentration, temps, etc

used to pass on genetic info of all cells

• nucleotide has deoxyribose as 5C sugar
• double helix structure (double strand of nucleotides)
• exists as two strands twisted into a helix
• the base adenine (A) hydrogen bonds with thymine (T)
• cytosice (C) hydrogen bonds with guanine (G)
• Found in nucleus of cells

• nucleotide has ribose as 5C sugar
• single chain nucleotide structure (single stranded)
• directs production of proteins
• -once synthesized (via DNA), moves out of nucleus to protein synthesis machinery in cell and base sequence directs which AA's are joined together
• 3 bases = particular AA

• differences between DNA and RNA:
• RNA's base is uracil (U) instead of thymine (T) in DNA
• The base adenine (A) hydrogen bonds with uracil (U)

polomers of nucleotides that are found inside of cells and control the genetic info of the cells

• nucleotide monomer made of 3 parts:
• 1. 5 C sugar-either Rubose or Deoxyribose
• 2. N-containing base
• -single ring pyrimidine: C, T, U
• -double ring purine: A, G
• 3. a phosphate group

• has ribose, adenine, and 3 phosphate groups
• ENERGY FOR CELL ACTIVITIES
• is made by dehydration synthesis
• is broken by hydrolysis to liberate useful energy for the cell
• ATP + WATER = ADP + P + ENERGY