AP Biology Unit One

water ratio

(1:2) ratio (Oxygen:Hydrogen)

covalent bonds

the bonding between hydrogen and oxygen molecules

polarity

oxygen is more electronegative than hydrogen; results in the unequal sharing of electrons or polarity (dual property of charges).

hydrogen bonds

oxygen area of a water molecule is negative, and the hydrogen area is positive; weak hydrogen bonds form between the negative and positive regions of a molecule.

e.g. Water can form hydrogen bonds with other water or charged molecules

cohesion

two of the SAME molecules form hydrogen bonds. 

e.g. The hydrogen bonds between two water molecules.

adhesion

two DIFFERENT molecules form hydrogen bonds.

e.g. Water droplets stick to a window or dew sticks on a leaf.

hydrophilic

water soluble substances

e.g. ionic compounds, polar molecules, and some proteins.

hydrophobic

substances that are non-polar and do not dissolve in water.

e.g. oil

surface tension

occurs when there is increased hydrogen bonding at the surface of water molecules.

e.g. a leaf floating on water

universal solvent

the adhesive and polar properties of water allows water to have high solvency in its liquid state.

ice floats

cohesive properties of water allows for unique hydrogen bonding when water is in its solid state; ice is less dense than water.

e.g. During winter periods, organisms can still survive below the surface of water, while still maintaining regular thermal energy

high heat capacity

cohesive properties of water allow for it to absorb a lot of thermal energy before changing chemical states, resisting sudden changes in temperature.

e.g. Allows water to regulate environmental temperature and increase survivability for organisms.

molecules

necessary to build new molecules

energy

cannot be destroyed, only transferred; iving systems need a constant input of energy to grow, reproduce, and maintain organization.

carbon

moves from the environment to organisms where it is used to build carbohydrates, proteins, lipids, or nucleic acids.

e.g. can easily form covalent bonds; a stable element.

nitrogen

moves from the environment to organisms where it is used in building nucleic acids, amino acids, and enzymes

plays a crucial role in metabolism, cell division, and DNA replication.

hormonal component in adrenaline + insulin

nitrogen cycle is used to balance nutrients in the ecosystem.

e.g. Plants and microorganisms convert nitrogen into usable forms (nitrogen fixation).

phosphorus

in nucleic acids, certain proteins, and lipids.

e.g. In DNA and RNA.

atoms

are the smallest component of life, with matter, they make elements; made up of protons (+), neutrons(/), and electrons (-).

atomic number

represents the number of protons an atom has in its nucleus;

atomic mass

number of protons + neutrons.

isotopes

two atoms of an element that have a different number of neutrons.

electron shells

an electron’s potential energy level.

e.g. When electrons absorb energy, they jump away from the nucleus.

monomers

chemical subunits used to create polymers.

polymer

macromolecules (large molecules) made of many monomers; specific to the monomers they consist of.

monosaccaride

carbohydrate

amino acid

protein

nucleotide

nucleic acid

fatty acid (glycerol)

lipid

dehydration synthesis

water is removed to break the covalent bonds between monomers (water becomes a bi-product).

hydrolysis

water is added to a polymer to break it apart into monomers.

carbohydrate

vary in structure and function

complex carbohydrates can have monomers whose structure determine the properties and functions of the carbohydrate.

serve as immediate energy (fuel), or building materials for a cell

e.g. Glucose serves as the main fuel for cells

function = structure

change in structure can lead to change in function

nucleic acids

biological information is encoded in sequences of nucleotide monomers; DNA and RNA differ in structure and function.

nucleotide structure

a five-carbon sugar (deoxyribose or ribose), a phosphate, and a nitrogen base (adenine, thymine, guanine, cytosine, or uracil).

DNA

deoxyribose, thymine

RNA

ribose, uracil

proteins

specific order of amino acids in a polypeptide (primary structure) determines the overall shape and linked by peptide bonds; ALWAYS have an amino group terminus and a carboxyl group terminus.

R groups

can be hydrophobic, hydrophilic, or ionic; determine structure and function of that region of the protein.

lipid

do not have true monomers but are composed of subunits like fatty acids and glycerol; differences in saturation determine the structure and function of lipids.

fatty acid components determine structure and function based on saturation.

saturation

when there are double bonds in the carbon skeleton.

phospholipids

specialized lipids that have a hydrophobic AND hydrophilic region, determining interactions with other molecules

phospholipid bi-layer

hydrophilic heads face toward the outer and inner aqueous environments of a cell; hydrophobic tails face toward each other to avoid aqueous interactions.

proteins

provide cells with structure, catalytic, signaling, defense, and transport within cells.

e.g. enzymes, hormones, storage, transport (membrane), defense proteins, and receptor proteins.

primary protein structure

sequence of amino acids connected through peptide bonds.

secondary protein structure

hydrogen bonding of backbones.

e.g. alpha helix, beta-pleated sheets.

tertiary protein structure

interactions between helix and sheets.

quaternary protein structure

interactions between two or more polypeptide chains (multi-subunit proteins). e.g. DNA Polymerase.

denaturing

occurs when proteins lose their tertiary structure through exposure to temperatures and pH levels outside a protein's optimal range.

replication + transcription

DNA and RNA in these processes are replicated and transcribed in the 5’ to 3’ direction; nucleotides are added to the 3’ end.

antiparallel

meaning that DNA strands run in different directions, one 5’ to 3’ and the other 3’ to 5’.

polysaccharide

multiple linked sugar units, complex carbohydrate.

disaccharide

two monosaccharides joined by a covalent bond through dehydration synthesis. e.g. Maltose, Sucrose, Lactose.