MB Ch2 Chemical Reactions & Organic Molecules

reactants (substrates)

materials going into reaction

products

materials coming out of reactions

metabolism

all reactions occurring at one time

work

change in mass or distance

energy

power to do work

kinetic energy

energy of motion; can be transferred to another object and perform work

potential energy

stored energy; has the potential to do work

chemical energy

potential energy stored in chemical bonds

synthesis reactions

form chemical bonds; A + B → AB

dehydration synthesis (condensation)

formation of a water molecule as a byproduct (water in products); ABC-H + OH-DE → ABCDE + H2O

anabolism

synthesis of new molecules within body cells that uses energy; A + B + energy → AB

decomposition reactions

break down chemical bonds; AB → A + B

hydrolysis

“water breaking” (water in reactants); ABCDE + H2O → ABC-H + HO-DE

catabolism

breakdown of complex molecules within body cells that produces energy; AB → A + B + energy

organic compounds (macromolecules)

molecules (covalently bonded) based on C and H (usually also contain O); contain functional groups that determine chemistry; includes carbohydrates, proteins, lipids, and nucleic acids

functional group

an arrangement of atoms in an organic molecule that is responsible for most of the chemical properties of that molecule

inorganic compounds

molecules not based on C and H

carbohydrates

• contain C, H, O in 1:2:1 ratio

• principal function: fuel cell activities with a ready source of energy

• other functions: building block of DNA and cell walls; components of cell membranes

• categories: monosaccharides, disaccharides, polysaccharides

monosaccharides

simple sugars with 3-7 C atoms; examples: glucose, fructose

disaccharides

2 monosaccharides condensed by dehydration synthesis; make up peptidoglycan and pseudomurein; examples: sucrose, lactose, maltose

polysaccharides

> 2 monosaccharides condensed by dehydration synthesis; examples: glycogen, chitin, cellulose,

glucose

C6H12O6; monosaccharide; important energy source for cells; most abundant monosaccharide

fructose

C6H12O6; monosacharide; alternate energy source for cells; structural isomer of glucose

peptidoglycan

forms cell wall of bacteria; made of a disaccharide and amino acids

pseudomurein

makes up cell wall of some archaea; made of a disaccharide and amino acids

glycogen

polysaccharide; stored form of glucose made of multiple glucose units

chitin

polysaccharide; forms cell wall of fungi and exoskeletons of crustaceans and insects

cellulose

polysaccharide; forms cell wall of plants and algae

lipids

• contain C and H in 1:2 ratio

• principal function: primary components of cell membranes

• nonpolar, hydrophobic molecules

• categories: simple, complex

simple lipids

fats or triglycerides; contain glycerol and fatty acids (fatty acids contain hydrocarbon chains); can be saturated or unsaturated; formed by dehydration synthesis; broken by hydrolysis

complex lipids

contain C, H, O, P, N, or S; phospholipids that make up membranes; have hydrophobic tails and hydrophilic heads

hydrophilic

“water loving”; interacts with water; ions and polar molecules

hydrophobic

“water fearing”; does not interact with water; nonpolar molecules, fats, oils