AP Bio Unit 1

polarity

• When there are differences in atomic electronegativities

• Water is polar due to the oxygen being negative and the hydrogen being positive

hydrogen bond

• A weak bond interaction between the negative and positive regions of 2 separate molecules

• Water molecules form hydrogen bonds with other water molecules

cohesion

When 2 of the same molecules form hydrogen bonds with each other

adhesion

When 2 different molecules form hydrogen bonds with each other

surface tension

• When many water molecules are bonded tightly together near the surface of the water

• Helps plants floating on the water with photosynthesis

solvency

When water molecules use adhesion to break apart other molecules

high heat capacity

Water’s cohesive property allows it to absorb a lot of thermal energy before changing chemical states, resisting sudden changes in temperature

capillary action

• Water can go up a tube with its cohesive and adhesive abilities

• Helps bring water up plant roots

carbon

• Used to build Carbohydrates, Lipids, Proteins, and Nucleic Acids

• Stores energy

• Builds basic cell structures

nitrogen

Used to build proteins and nucleic acids

phosphorous

Used to build certain lipids and nucleic acids

monomers

• Chemical subunits used to create polymers

• Connect to other monomers through covalent bonds

polymer

A macromolecule made of many monomers

dehydration synthesis

• OH and H come off of 2 monomers, joining the monomers together with a covalent bond

• H2O is the byproduct

hydrolysis

• H2O splits apart a polymer

• Opposite of dehydration synthesis

nucleic acids

• 3’ hydroxyl end and 5’ phosphate end

• Antiparallel 5’-3’ direction

adenine-thymine bond

• Held together by 2 hydrogen bonds

• Destabilizes faster than guanine-cytosine

guanine-cytosine

• Held together by 3 hydrogen bonds

• Destabalizes slower than adenine-thymine

amino acids

Held together by covalent bonds from dehydration synthesis

primary structure of proteins

Determined by the sequence of amino acids held together by covalent bonds, called peptide bonds

secondary structure of proteins

Arises through local folding of the amino acid chain into elements such as alpha-helices and beta-sheets

tertiary structure of proteins

• The overall 3D shape of the protein and often minimizes free energy

• Various types of bonds and interactions stabilize the protein at this level

quaternary structure of proteins

Arises from the interactions between multiple polypeptide units

carbohydrates

Held together by covalent bonds from dehydration synthesis

DNA

• Double-stranded

• Contains thymine

• Deoxyribose sugar

RNA

• Single-stranded

• Contains uracil

• Ribose sugar