AP Bio Unit 1

From Princeton Review Book

Elements

Elements

substances that connot be broken down into simpler substances by chemical means

isotopes

when some atoms have the same number of protons but differ in the number of neutrons

compound

when two or more individual elements are combined in a fixed ratio

ionic bond

formed between two atoms when one or more electrons are transferred from one atom to another

ions

charged forms of an atom

covalent bonds

formed when electrons are shared between atoms

nonpolar covalent

when electrons are shared equally between atoms

polar covalent

when electrons are shared unequally

polar

molecules that have partially positive and partially negative charges

hydrogen bonds

weak chemical bonds that from when a hydrogen atom that is covalently bonded to one electronegative atom is also attracted to another electronegative atom

cohesion

the ability of water molecules sticking together

transpiration

when water molecules evaporate from a leaf, pulling on neighboring water molecules drawing up the molecules enabling water to move up the stem

adhesion

water molecules sticking to other substances

capillary action

when cohesion and adhesion occurs in thin vessels

acidic solution

when it contains a lot of hydrogen ions (H+)

basic solution

when it contains a lot of hydroxide ions (OH-)

alkaline

a basic solution

pH scale

a scale that is numbered from 1 to 14 measuring the concentration of hydrogen ions in a solution

acidic range on the pH scale

<7

basic range on the pH scale

7

neutral pH range

7

organic compounds

molecules that contain carbon and oxygen

inorganic compounds

molecules that do not contain carbon molecules

polymers

Large molecules made up of repeating units called monomers

Ex. proteins

monomers

building blocks of polymers

dehydration synthesis

when a water molecule is lost and a larger compound is formed

hydrolysis

when water breaks the bond between the two monomers

Carbohydrates

organic compounds that contain Carbon, Hydrogen, and Oxygen

CHO

monosaccharides

one sugar

disaccharides

two sugars

polysaccharides

many sugars

glycosidic linkage

when two monosaccharides are joined

Proteins

organic molecules that contain carbon, hydrogen, oxygen and nitrogen atoms

perform most of the work in you cells

amino acids

building blocks of proteins

four important parts of an amino acid

1. amino group (NH2)

2. Carboxyl group (COOH)

3. Hydrogen

4. R-group

hydrophobic

non-polar and uncharged molecules that don’t like water

hydrophilic

polar and uncharged molecules that like water

dipeptide

when two amino acids join

peptide bond

when two amino acids bond

polypeptide

when a group of amino acids joins together in a string

protein

when a polypeptide chain twists and folds on itself forming a three-dimensional structure

primary structure

when the amino acids are in a linear sequence

secondary structure

when the polypeptide forms either an alpha helix or a beta-pleated sheet

tertiary structure

when the polypeptide reshapes so that the r-groups interact with each other

quaternary structures

when different polypeptide chains interact with each other

chaperone proteins (chaperonins)

proteins involved in the folding of other proteins that help it fold properly and make the process more efficient

Lipids

organic molecules consisting of carbon, hydrogen, oxygen and sometimes phosphorus

function as structural components of cell membranes, energy storage and insulation, and signaling molecules

saturated fatty acid

a fatty acid with hydrogens along its long carbon chain, no double bonds

unsaturated fatty acids

when there is a double bond in the chain so not all carbons have two hydrogens

phospholipids

lipids that contain two fatty acid" “tails” and one negatively charged phosphate “head”

amphipathic molecule

a molecule that has both a hydrophilic region and a hydrophobic region

Ex. phospholipids

Cholesterol

a four-ringed molecule that is found here and there in a membrane

type of lipid, increases membrane fluidity except at high temperatures when it helps to hold things together instead

Nucleic Acid

an organic compound that contains carbon, hydrogen, oxygen, and nitrogen as well as sometimes phosphorus

nucleotides

make up nucleic acids

deoxyribonucleic acid (DNA)

a polymer of nucleic acids that contains the hereditary “blueprints” for all life

ribonucleic acid (RNA)

a polymer of nucleic acids that is essential for protein synthesis