AP Biology Unit 1

Chemistry of Life

hydrogen bonding

bonds between the oxygen and hydrogens of different water molecules

oxygen atoms in H2O

portion with a slightly negative charge

hydrogen atom in H2O

portion with a slightly positive charge

cohesion

attraction of molecules of the same kind through hydrogen bonds

electronegativity

tendency to attract and hold shared electrons when forming bonds

i.e. oxygen atoms has a higher electronegativity than hydrogen

cohesion

attraction of molecules of the same kind through hydrogen bonds

surface tension

polar molecules stick together rather than disbanding

adhesion

attraction of molecules of different kind through hydrogen bonds

capillary action

upward movement of water due to cohesion, adhesion, and surface tension

high specific heat

water is resistant to changes in temperature by hydrogen bonds

high heat of vaporization

takes a lot of energy for water to evaporatee

evaporative cooling

takes heat away when evaporating

structure of water (liquid)

crystalline lattice structure

universal solvent

attracts ions and other polar molecules

benefits of ice

1) creates insulation for heat for animals living in water

2) reflects sun rays and decrease the heat absorption of the Earth’s surface

3) serves as a habitat for Arctic & Antarctic animals

organic compounds

any compound that contains both C & H

law of the conservation of energy

energy cannot be created nor destroyed

Why do living systems require a constant input of energy?

1) growth

2) reproduction

3) organization

Where is energy stored in the body?

in the chemical bonds of macromolecules

hydrocarbon

only contain carbon and hydrogen; framework for more complex molecules

variation in hydrocarbons

vary in length, branching, rings, double-bonds

types of macromolecules

carbohydrates, proteins, nucleic acids, lipids

polymers

chain-like molecules of monomers

monomers

the building blocks of polymers

dehydration

bonds two monomers by taking away H2O

hydrolysis

breaks a polymer by adding H2O

carbohydrate

sugars and polymers of sugars

CHO

structure of carbohydrate

a carbonyl group and many hydroxyl groups

types of carbohydrates

monosaccharides, disaccharides, polysaccharides

storage polysaccharides

plants store starch, animals store glycogen

structure polysaccharides

cellulose forms plant cell walls; chitin forms exoskeleton

amino acids

monomers of proteins

CHONS

polypeptides

many amino acids linked by peptide bonds; has a free amino group (N-terminus), has a free carboxyl group (C-terminus)

primary structure

linear chain of amino acids

secondary structure

alpha helix + beta sheet

tertiary structure

3D folding

quaternary structure

2 or more tertiary polypeptides forming a protein

protein function

antibodies, enzymes, messengers, structural support, storage

nucleic acids

polymers of nucleotides

CHONPS

pyrimidines

nucleobases with one ring (CUT)

purines

nucleobases with two ring (AG)

nucleotide structure

nitrogenous base + 5-carbon sugar + phosphate group

phosphodiester bonds

the bonds between phosphate groups of adjacent nucleotides

DNA structure

two polynucleotide chains, forms a double helix, strands are anti-parallel

RNA structure

single-stranded polynucleotide

lipids

non-polar molecules => hydrophobic; don’t have “polymers”

CHO(P for phospholipids)

types of lipids

fats, phospholipids, steroids

ester bonds

bonds that form fats

unsaturated fat

has double bonds => more liquid => healthier

phospholipids

component of membranes

steroids

lipids that have 4 fused rings; used in cell-signaling