unit 1- the chemistry of life

does not go in depth of proteins

atomic number

number of protons

atomic mass number

number of protons + neutrons

neutral atom

the number of electrons = the number of protons

ionic bonds

electrons are transferred from one atom to another to create filled outer shells (metal gives and non-metal takes)

cation

loses an electron, so a positively charged ion

anion

 gains an electron, so a negatively charged ion

covalent bond

involve the sharing of electrons, making them very strong

nonpolar

the charge is equally distributed across the molecule

polar

occurs when atoms in a bond have different electronegativities and share electrons unequally

hydrogen bonds

form between neighboring hydrogen (relatively positive charge) and oxygen (relatively negative charge) atoms of adjacent water molecules

pH scale

goes from 0-14 and has a tenfold change in h+ ions

acids

more hydronium ions than hydroxide ions and pH lower than 7

bases

more hydroxide ions than hydronium ions, and pH higher than 7

buffers

buffers are composed of a weak acid and its conjugate base and it is used to control pH (can both give or take hydronium ions)

maximum amount of hydrogen bonds water can make

4

cohesion

hydrogen bonding between H20 molecules and causes surface tension

adhesion

hydrogen bonding between H20 and other polar substances and causes capillary action, imbibition, and meniscus

Transpiration

built on cohesion and adhesion + drives photosynthesis in plants

why water is a good solvent

polar H2O molecules surround + & – ions and dissociation occurs

why ice floats

As water cools, the water molecules slow down and, as a result, the hydrogen bonds between them become more stable. Hence, as ice forms the hydrogen bonds cause the water molecules to space out in a crystalline form. + it’s less dense that H20

benefits of ice floating

surface ice INSULATES water below- reduces heat loss so water below is warmer, allowing life to survive the winter

specific heat

the amount of energy needed to heat or cool a substance by one degree celsius

why does water have a high specific heat

it takes a lot of energy to break the bonds between water molecules and raise it by one degree

benefits of water having a high specific heat

water resists changes in temperature and moderates temperatures on earth

heat of vaporization

amount of energy needed to change one gram of liquid into gas at a constant temp.

why does water have a high heat of vaporization

because of the amount of energy it takes to break the hydrogen bond between 2 water molecules is a lot

carbon’s bonds

carbon only forms covalent bonds and can make up to 4 single bonds

hydrocarbons

carbon forms large chains with hydrogen and these are nonpolar and hydrophobic

isomers

molecules with the same molecular formula but different structures, giving them different chemical properties and biological functions

enzymes

required for most biological reactions with living organisms. they function as biological catalysts, accelerating chemical reactions by lowering the activation energy needed

5 functional groups

hydroxyl, carboxyl, amino(amine), sulfhydryl, and phosphate

hydroxyl OH

increases the solubility of organic molecules (alcohol)

carboxyl COOH

acts as an acid by releasing H+ into the solution and can be found in amino acids and fatty acids.

amino(amine) NH2

acts as a base by picking up H+ from the solution, leaving excess OH-, making the solution less acidic

sulfhydryl SH

stabilizes the structure of proteins, forms disulfide bridges(bonds)

phosphate PO4

transfers energy between organic molecules like ATP and GTP and has lots of negative charge( highly reactive)

4 major classes of macromolecules (polymers)

carbohydrates, lipids, proteins, and nucleic acids

carbohydrates CHO

-1:2:1 ratio of CHO

-monomers= monosaccharides, glucose, etc.

-examples: glucose, starch, glycogen, cellulose, chitin

glucose

energy source

starch

energy storage in plants

glycogen

energy storage in animals

cellulose

cell wall structure in plants (fiber)

chitin

exoskeleton in arthropods & cell wall in fungi

lipids CHO

-monomers=fatty acids and glycerol

-examples: phospholipids, steroids, and triglycerides

phospholipids

cell membranes (think of phospholipid bilayers)

steroids

cholesterol (maintains cell membrane fluidity), hormones like testosterone & estradiol

triglycerides

-fats and oils (main energy storage)

-one glycerol head and 3 fatty acid tails

-examples: saturated and unsaturated fats

saturated fat

the carbons are saturated (bonded) with hydrogens so the molecules pack closely together and have strong attractions between the fatty acids...solid at room temperature

unsaturated fat

has at least 1 double bond between 2 carbons (so NOT saturated with hydrogens)... causes a kink in their structure...they can’t pack as tightly together… liquid at room temperature

nucleic acids CHONP

-monomers=nucleotides

-examples: DNA and RNA

DNA

-double helix

-genetic code/ recipe/ information

-composed of ATCG

-sugar is deoxyribose

-held by sugar phosphate backbone

RNA

-can be one or two strands

-carries genetic information and acts as catalyst

-composed of AUCG

-sugar is ribose

proteins CHON(S)

monomers=amino acids

dehydration synthesis(condensation reaction)

-joins monomers together to make a larger molecule (ex: a polymer), by removing H₂O out

-requires an input of energy & enzymes

-example: photosynthesis

hydrolysis(digestion)

-use H₂O to break down polymers (hydrolyze)

-requires enzymes & releases energy

-example: respiration

anabolic steroids

synthetic (man-made) versions of testosterone that help build muscle tissue and increase body mass by mimicking the body’s natural male hormone, as they have the same/similar 3D conformation as testosterone